Vitamin D

Are Vegan Diets Bad For Your Bones?

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The Secrets To A Healthy Vegan Diet

Author: Dr. Stephen Chaney

Frail ElderlyOsteoporosis is a debilitating and potentially deadly disease associated with aging. It affects 54 million Americans. It can cause debilitating back pain and bone fractures. 50% of women and 25% of men over 50 will break a bone due to osteoporosis. Hip fractures in the elderly due to osteoporosis are often a death sentence.

As I discussed in a previous issue of “Health Tips From The Professor”, a “bone-healthy lifestyle requires 3 essentials – calcium, vitamin D, and weight bearing exercise. If any of these three essentials is presence in inadequate amounts, you can’t build healthy bones. In addition, other nutrients such as protein, magnesium, zinc, vitamin B12, and omega-3 fatty acids may play supporting roles.

Vegan and other plant-based diets are thought to be very healthy. They decrease the risk of heart disease, diabetes, and some cancers. However, vegan diets tend to be low in calcium, vitamin D, zinc, vitamin B12, protein, and omega-3 fatty acids. Could vegan diets be bad for your bones?

A meta-analysis of 9 studies published in 2009 (LT Ho-Pham et al, American Journal of Clinical Nutrition 90: 943-950, 2009) reported that vegans had 4% lower bone density than omnivores, but concluded this difference was “not likely to be clinically relevant”.

However, that study did not actually compare bone fracture rates in vegans and omnivores. So, investigators have followed up with a much larger meta-analysis (I Iguacel et al, Nutrition Reviews 77, 1-18, 2019) comparing both bone density and bone fracture rates in vegans and omnivores.

How Was This Study Done?

Clinical StudyThe investigators searched the literature for all human clinical studies through November 2017 that compared bone densities and frequency of bone fractures of people consuming vegan and/or vegetarian diets with people consuming an omnivore diet.

  • Vegan diets were defined as excluding all animal foods.
  • Vegetarian diets were defined as excluding meat, poultry, fish, seafood, and flesh from any animal but including dairy foods and/or eggs. [Note: The more common name for this kind of diet is lacto-ovo vegetarian, but I will use the author’s nomenclature in this review.]
  • Omnivore diets were defined as including both plant and animal foods from every food group.

The investigators ended up with 20 studies that had a total of 37,134 participants. Of the 20 studies, 9 were conducted in Asia (Taiwan, Vietnam, India, Korea, and Hong-Kong), 6 in North America (the United States and Canada), and 4 were conducted in Europe (Italy, Finland, Slovakia, and the United Kingdom).

Are Vegan Diets Bad For Your Bones?

Here is what the investigators found:

Unhealthy BoneBone density: The clinical studies included 3 different sites for bone density measurements – the lumbar spine, the femoral neck, and the total body. When they compared bone density of vegans and vegetarians with the bone density of omnivores, here is what they found:

Lumbar spine:

    • Vegans and vegetarians combined had a 3.2% lower bone density than omnivores.
    • The effect of diet was stronger for vegans (7% decrease in bone density) than it was for vegetarians (2.3% decrease in bone density).

Femoral neck:

    • Vegans and vegetarians combined had a 3.7% lower bone density than omnivores.
    • The effect of diet was stronger for vegans (5.5% decrease in bone density) than it was for vegetarians (2.5% decrease in bone density).

Whole body:

    • Vegans and vegetarians combined had a 3.2% lower bone density than omnivores.
    • The effect of diet was statistically significant for vegans (5.9% decrease in bone density) but not for vegetarians (3.5% decrease in bone density). [Note: Statistical significance is not determined by how much bone density is decreased. It is determined by the size of the sample and the variations in bone density among individuals in the sample.]

Bone FractureBone Fractures: The decrease in bone density of vegans in this study was similar to that reported in the 2009 study I discussed above. However, rather than simply speculating about the clinical significance of this decrease in bone density, the authors of this study also measured the frequency of fractures in vegans, vegetarians, and omnivores. Here is what they found.

  • Vegans and vegetarians combined had a 32% higher risk of bone fractures than omnivores.
  • The effect of diet on risk of bone fractures was statistically significant for vegans (44% higher risk of bone fracture) but not for vegetarians (25% higher risk of bone fractures).
  • These data suggest the decreased bone density in vegans is clinically significant.

The authors concluded, “The findings of this study suggest that both vegetarian and vegan diets are associated with lower bone density compared with omnivorous diets. The effect of vegan diets on bone density is more pronounced than the effect of vegetarian diets, and vegans have a higher fracture risk than omnivores. Both vegetarian and vegan diets should be appropriate planned to avoid dietary deficiencies associated with bone health.”

The Secrets To A Healthy Vegan Diet

Emoticon-BadThe answer to this question lies in the last statement in the author’s conclusion, “Both vegetarian and vegan diets should be appropriate planned to avoid dietary deficiencies associated with bone health.” 

The problem also lies in the difference between what a nutrition expert considers a vegan diet and what the average consumer considers a vegan diet. To the average consumer a vegan diet is simply a diet without any animal foods. What could go wrong with that definition? Let me count the ways.

  1. Sugar and white flour are vegan. A vegan expert thinks of a vegan diet as a whole food diet – primarily fruits, vegetables, whole grains, beans, nuts, and seeds. A vegan novice includes all their favorites – sodas, sweets, and highly processed foods. And that may not leave much room for healthier vegan foods.

2) Big Food, Inc is not your friend. Big Food tells you that you don’t need to give up the taste of animal foods just because you are going vegan. They will just combine sugar, white flour, and a witch’s brew of chemicals to give you foods that taste just like your favorite meats and dairy foods. The problem is these are all highly processed foods. They are not healthy. Some people call them “fake meats” or “fake cheeses”. I call them “fake vegan”.

If you are going vegan, embrace your new diet. Bean burgers may not taste like Big Macs, but they are delicious. If need other delicious vegan recipe ideas, I recommend the website https://forksoverknives.com.

3) A bone healthy vegan diet is possible, but it’s not easy. Let’s go back to the author’s phrase “…vegan diets should be appropriate planned to avoid dietary deficiencies associated with bone health.” A vegan expert will do the necessary planning. A vegan novice will assume all they need to do is give up animal foods. 

As I said earlier, vegan diets tend to be low in calcium, vitamin D, zinc, vitamin B12, protein, and omega-3 fatty acids. Let’s look at how a vegan expert might plan their diet to get enough of those bone-healthy nutrients.

    • Calcium. The top plant sources of calcium are leafy greens and soy foods at about 100-250 mg (10-25% of the DV) of calcium per serving. Some beans and seeds are moderately good sources of calcium. Soy foods are a particularly good choice because they are a good source of calcium and contain phytoestrogens that stimulate bone formation.

A vegan expert makes sure they get these foods every day and often adds a calcium supplement.

    • Protein. Soy foods, beans, and some whole grains are the best plant sources of protein.soy

It drives me crazy when a vegan novice tells me they were told they can get all the protein they need from broccoli and leafy greens. That is incredibly bad advice.

A vegan expert makes sure they get soy foods, beans, and protein-rich grains every day and often adds a protein supplement.

    • Zinc. There are several plant foods that supply around 20% the DV for zinc including lentils, oatmeal, wild rice, squash and pumpkin seeds, quinoa, and black beans.

A vegan expert makes sure they get these foods every day and often adds a multivitamin supplement containing zinc.

    • Vitamin D and vitamin B12. These are very difficult to get from a vegan diet. Even vegan experts usually rely on supplements to get enough of these important nutrients.

4) Certain vegan foods can even be bad for your bones. I divide these into healthy vegan foods and unhealthy “vegan” foods. 

    • Healthy vegan foods that can be bad for your bones include.
      • Pinto beans, navy beans, and peas because they contain phytates.
      • Raw spinach & swiss chard because they contain oxalates.
      • Both phytates and oxalates bind calcium and interfere with its absorption.
      • These foods can be part of a healthy vegan diet, but a vegan expert consumes them in moderation.
    • Unhealthy “vegan” foods that are bad for your bones include sodas, salt, sugar, and alcohol.
      • The mechanisms are complex, but these foods all tend to dissolve bone.
      • A vegan expert minimizes them in their diet.

5) You need more than diet for healthy bones. At the beginning of this article, I talked about the 3 Weight Trainingessentials for bone formation – calcium, vitamin D, and exercise. You can have the healthiest vegan diet in the world, but if you aren’t getting enough weight bearing exercise, you will have low bone density. Let me close with 3 quick thoughts:

    • None of the studies included in this meta-analysis measured how much exercise the study participants were getting.
    • The individual studies were generally carried out in industrialized countries where many people get insufficient exercise.
    • The DV for calcium in the United States is 1,000-1,200 mg/day for adults. In more agrarian societies dietary calcium intake is around 500 mg/day, and osteoporosis is almost nonexistent. What is the difference? These are people who are outside (vitamin D) doing heavy manual labor (exercise) in their farms and pastures every day.

In summary, a bone healthy vegan lifestyle isn’t easy, but it is possible if you work at it.

The Bottom Line 

A recent meta-analysis asked two important questions about vegan diets.

  1.     Do vegans have lower bone density than omnivores?

2) Is the difference in bone density clinically significant? Are vegans more likely to suffer from bone fractures?

The study found that:

  • Vegans had 5.5%–7% lower bone density than omnivores depending on where the bone density was measured.
  • Vegans were 44% more likely to suffer from bone fractures than omnivores.

The authors of the study concluded, ““The findings of this study suggest that…vegan diets are associated with lower bone density compared with omnivorous diets, and vegans have a higher fracture risk than omnivores…Vegan diets should be appropriate planned to avoid dietary deficiencies associated with bone health.”

In evaluating the results of this study, I took a detailed look at the pros and cons of vegan diets and concluded, “A bone healthy vegan lifestyle isn’t easy, but it is possible if you work at it.”

For more details about study and my recommendations for a bone healthy vegan lifestyle read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease.

Which Diets Are Best In 2021?

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Which Diet Should You Choose?

Emoticon-BadMany of you started 2021 with goals of losing weight and/or improving your health. In many cases, that involved choosing a new diet. That was only 2 months ago, but it probably feels like an eternity.

For many of you the “bloom” has gone off the new diet you started so enthusiastically in January.

  • Perhaps the diet isn’t working as well as advertised…
  • Perhaps the diet is too restrictive. You are finding it hard to stick with…
  • Perhaps you are always hungry or constantly fighting food cravings…
  • Perhaps you are starting to wonder whether there is a better diet than the one you chose in January…
  • Perhaps you are wondering whether the diet you chose is the wrong one for you…

If you are rethinking your diet, you might want to know which diets the experts recommend. Unfortunately, that’s not as easy as it sounds. The diet world has become just as divided as the political world.

Fortunately, you have an impartial resource. Each year US News & World Report invites a panel of experts with different points of view to evaluate popular diets. They then combine the input from all the experts into rankings of the diets in various categories.

If you are still searching for your ideal diet, I will summarize the US News & World Report’s “Best Diets In 2021”. For the full report, click on this link.

How Was This Report Created?

Expert PanelUS News & World Report recruited panel of 25 nationally recognized experts in diet, nutrition, obesity, food psychology, diabetes, and heart disease to review the 39 most popular diets.  They rated each diet in seven categories:

  • How easy it is to follow.
  • Its ability to produce short-term weight loss.
  • Its ability to produce long-term weight loss.
  • its nutritional completeness.
  • Its safety.
  • Its potential for preventing and managing diabetes.
  • Its potential for preventing and managing heart disease.

They converted the experts’ ratings to scores 5 (highest) to 1 (lowest). They then used these scores to construct nine sets of Best Diets rankings:

  • Best Diets Overall combines panelists’ ratings in all seven categories. However, all categories were not equally weighted. Short-term and long-term weight loss were combined, with long-term ratings getting twice the weight. Why? A diet’s true test is whether it can be sustained for years. And safety was double counted because no diet should be dangerous.
  • Best Commercial Diets uses the same approach to rank 15 structured diet programs that require a participation fee or promote the use of branded food or nutritional products.
  • Best Weight-Loss Diets was generated by combining short-term and long-term weight-loss ratings, weighting both equally. Some dieters want to drop pounds fast, while others, looking years ahead, are aiming for slow and steady. Equal weighting accepts both goals as worthy.
  • Best Diabetes Diets is based on averaged diabetes ratings.
  • Best Heart-Healthy Diets uses averaged heart-health ratings.
  • Best Diets for Healthy Eating combines nutritional completeness and safety ratings, giving twice the weight to safety. A healthy diet should provide sufficient calories and not fall seriously short on important nutrients or entire food groups.
  • Easiest Diets to Follow represents panelists’ averaged judgments about each diet’s taste appeal, ease of initial adjustment, ability to keep dieters from feeling hungry and imposition of special requirements.
  • Best Plant-Based Diets uses the same approach as Best Diets Overall to rank 12 plans that emphasize minimally processed foods from plants.
  • Best Fast Weight-Loss Diets is based on short-term weight-loss ratings.

Which Diets Are Best In 2021?

The word WInner in white letters surrounded by a burst of colorful stars in 3d

Are you ready? If this were an awards program I would be saying “Envelop please” and would open the envelop slowly to build suspense.

However, I am not going to do that. Here are the top 5 and bottom 5 diets in each category (If you would like to see where your favorite diet ranked, click on this link). [Note: I excluded commercial diets from this review.]

Best Diets Overall 

The Top 5: 

#1: Mediterranean Diet

#2: DASH Diet (This diet was designed to keep blood pressure under control, but you can also think of it as an Americanized version of the Mediterranean diet.)

#3: Flexitarian Diet (A flexible semi-vegetarian diet).

#4: Mayo Clinic Diet

#5: MIND Diet (This diet is a combination of Mediterranean and DASH but is specifically designed to reduce cognitive decline as we age.)

The Bottom 5: 

#35: Modified Keto Diet

#36: Whole 30 Diet

#37: GAPS Diet (A diet designed to improve gut health).

#38: Keto Diet

#39: Dukan Diet

Best Weight-Loss DietsWeight Loss

The Top 5: 

#1: Flexitarian Diet

#2: Vegan Diet

#3: Volumetrics Diet (A diet based on the caloric density of foods).

#4: Mayo Clinic Diet

#5: Ornish Diet

The Bottom 5: 

#35: Fertility Diet

#36: Whole 30 Diet

#37: Alkaline Diet

#38: AIP Diet (A diet designed for people with autoimmune diseases)

#39: GAPS Diet

Best Diabetes Diets

The Top 5: 

#1: Flexitarian Diet

#2: Mediterranean Diet

#3: DASH Diet

#4: Mayo Clinic Diet

#5: Vegan Diet

The Bottom 5: 

#35: The Fast Diet

#36: AIP Diet

#37: GAPS Diet

#38: Whole 30 Diet (A diet designed for people with autoimmune diseases)

#39: Dukan Diet

strong heartBest Heart-Healthy Diets 

The Top 5: 

#1: DASH Diet

#2: Mediterranean Diet

#3: Ornish Diet (A diet based on the caloric density of foods).

#4: Flexitarian Diet

#5: Vegan Diet

The Bottom 5: 

#35: Keto Diet

#36: AIP Diet

#37: Whole 30 Diet

#38: Modified Keto Diet

#39: GAPS Diet

Best Diets for Healthy Eating

The Top 5: 

#1: DASH Diet

#2: Mediterranean Diet

#3: Flexitarian Diet

#4: TLC Diet (A diet designed to promote heart health)

#5: MIND Diet

The Bottom 5: 

#35: Atkins Diet

#36: Raw Food Diet

#37: Modified Keto Diet

#38: Dukan Diet

#39: Keto Diet 

Easiest Diets to FollowEasy

The Top 5: 

#1: Mediterranean Diet

#2: Flexitarian Diet

#3: MIND Diet

#4: DASH Diet

#5: Fertility Diet

The Bottom 5: 

#35: Keto Diet and Modified Keto Diet (tie)

#36: Whole 30 Diet

#37: Dukan Diet

#38: GAPS Diet

#39: Raw Foods Diet 

Best Fast Weight-Loss Diets

The Top 5 (Excluding Commercial Diets): 

#1: Atkins Diet

#2: Biggest Loser Diet

#3: Keto Diet

#4: Raw Food Diet

#5: Volumetrics Diet

Which Diets Are Best For Rapid Weight Loss?

Happy woman on scaleLet me start with some general principles:

#1: If you are looking for rapid weight loss, any whole food restrictive diet will do.

  • The Atkins and keto diets are meat heavy, low carb diets. They restrict fruits, some vegetables, grains, and most legumes.
  • The Biggest Loser diet relies on restrictive meal plan and exercise programs.
  • The restrictions of the raw food diet are obvious.
  • The volumetrics diet restricts foods with high caloric density.
  • The vegan diet, which ranks #7 on this list, is a very low fat diet that eliminates meat, dairy, eggs, and animal fats.
  • I did not include commercial diets that rated high on this list, but they are all restrictive in one way or another.

#2: Restrictive diets ultimately fail.

  • The truth is 90-95% of people who lose weight quickly on a restrictive diet regain most of that weight in the next two years. The pounds come back and often bring their friends along as well. Many people regain more weight than they lost. This is the famous “Yo-Yo Effect”.
  • If dieters paid for one of the commercial diets, they may as well have burned their money.
  • When I talk with people about weight loss, many of them tell me the Atkins diet is the only one they can lose weight on. That would be impressive if they were at a healthy weight, but most are not. They are overweight. I am starting to see the same thing from overweight people who have used the keto diet to lose weight and have regained their weight.

#3: We should ask what happens when we get tired of restrictive diets and add back some of your favorite foods.

  • If you lose weight on a vegan diet and add back some of your favorite foods, you might end up with a semi-vegetarian diet. This is a healthy diet that can help you maintain your weight loss.
  • If you lose weight on the Atkins or keto diets and add back some of your favorite foods, you end up with the typical American diet – one that is high in both fat and carbs. This is not a recipe for long-term success.
  • Long term weight loss is possible if you transition to a healthy diet after you have lost the weight. In a recent article in “Health Tips From The Professor” I wrote about an organization called the National Weight Control Registry. These are people who have been successful at keeping the weight off. For purposes of this discussion, two points are important.
  • They lost weight on every possible diet.
  • They kept the weight off by following a healthy reduced calorie, low fat diet. (For what else they did, click here).

Which Diet Should You Choose?

Which Diet Is BestWith rapid weight loss out of the way, let’s get back to the question, “Which Diet Should You Choose?” My recommendations are:

  • Choose a diet that fits your needs. That is one of the things I like best about the US News & World Report ratings. The diets are categorized. If your main concern is diabetes, choose one of the top diets in that category. If your main concern is heart health… You get the point.
  • Choose diets that are healthy and associated with long term weight loss. If that is your goal, you will notice that primarily plant-based diets top these lists. Meat-based, low carb diets like Atkins and keto are near the bottom of the lists.
  • Choose diets that are easy to follow. The less-restrictive primarily plant-based diets top this list – diets like Mediterranean, DASH, MIND, and flexitarian.
  • Choose diets that fit your lifestyle and dietary preferences. For example, if you don’t like fish and olive oil, you will probably do much better with the DASH or flexitarian diet than with the Mediterranean diet.
  • Finally, focus on what you have to gain, rather than on foods you have to give up.
    • On the minus side, none of the diets include sodas, junk foods, and highly processed foods. Teose foods should go on your “No-No” list. Sweets should be occasional treats and only as part of a healthy meal. Meat, especially red meat, should become a garnish rather than a main course.
    • On the plus side, primarily plant-based diets offer a cornucopia of delicious plant foods you probably didn’t even know existed. Plus, for any of the top-rated plant-based diets, there are websites and books full of mouth-watering recipes. Be adventurous.

The Bottom Line 

For many of you the “bloom” has gone off the new diet you started so enthusiastically in January. If you are rethinking your diet, you might want to know which diets the experts recommend. Unfortunately, that’s not as easy as it sounds. The diet world has become just as divided as the political world.

Fortunately, you have an impartial resource. Each year US News & World Report invites a panel of experts with different points of view to evaluate popular diets. They then combine the input from all the experts into rankings of the diets in various categories. In the article above I summarize the US News & World Report’s “Best Diets In 2021”.

There are probably two questions at the top of your list.

#1: Which diets are best for rapid weight loss? Here are some general principles:

  • If you are looking for rapid weight loss, any whole food restrictive diet will do.
  • Restrictive diets ultimately fail.
  • We should ask what happens when we get tired of restrictive diets and add back some of our favorite foods.
  • Long term weight loss is possible if you transition to a healthy diet after you have lost the weight.

#2: Which diet should you choose? Here the principles are:

  • Choose a diet that fits your needs.
  • Choose diets that are healthy and associated with long term weight loss.
  • Choose diets that are easy to follow.
  • Choose diets that fit your lifestyle and dietary preferences.
  • Finally, focus on what you have to gain, rather than on foods you have to give up.

For more details on the diet that is best for you, read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease.

Does Vitamin D Affect IQ?

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The Importance Of Vitamin D During Pregnancy

Author: Dr. Stephen Chaney

pregnant women taking vitaminAs an expectant mother, you want the best for your child. You want them to be healthy and happy. You probably also want them to be smart.

Your doctor has recommended you take a prenatal supplement. You have probably heard about the importance of folic acid for a successful pregnancy. I have also written about the importance of adequate omega-3s and iodine during pregnancy for the cognitive development of your child.

But what about vitamin D? Vitamin D receptors are expressed in the mammalian brain as early as 12 days into gestation, and vitamin D is thought to be important in neurocognitive development.

Previous studies have shown that vitamin D deficiency during pregnancy is associated with delayed motor-skill and social development during the first few years of childhood. But it is uncertain whether these early deficits translate into long-term deficits in IQ and emotional stability.

This study was designed to answer that question by comparing blood 25-hydroxyvitamin D levels in the mother’s blood during the second trimester and IQ measurements of their children between the ages of 4 and 6.

How Was This Study Done?

Clinical StudyThis study used data from the CANDLE (Conditions Affecting Neurocognitive Development and Learning in Early Childhood) database. This portion of the study measured blood levels of 25-hydroxyvitamin D during the second trimester of pregnancy of 1503 women from the Memphis area of Tennessee. The 25-hydroxyvitamin D levels were compared with the IQ of their children measured between the ages of 4 and 6.

The average age of the mothers was 26 and 63% of them were black.

Of course, there are many other factors that influence mental development during childhood. Accordingly, the data were corrected for the overall quality of the maternal diet, maternal IQ, maternal education, maternal age, marital status, BMI (a measure of obesity), tobacco use during pregnancy, alcohol use during pregnancy, and household income.

Does Vitamin D Affect IQ?

child geniusHere are the results from the study:

  • The average blood level of 25-hydroxyvitamin D at week 23 of pregnancy was 21.6 ng/mL.
    • 45.6% of the women were vitamin D deficient (<20 ng/mL 25-hydroxyvitamin D).
  • The average blood level of 25-hydroxyvitamin D in this study was 19.8 ng/mL for Black women and 25.9 ng/mL for White women.
    • This is consistent with a previous report that 80% of Black pregnant women in this country are vitamin D deficient compared to only 13% of White pregnant women.
  • After adjusting for other variables known to affect IQ, every 10ng/mL increase in 25-hydroxyvitamin D status during pregnancy resulted in an increase of:
    • 1.17 points in overall IQ.
    • 1.17 points in verbal IQ.
    • 1.03 points in nonverbal IQ.
  • The effect of vitamin D status during pregnancy on IQ of the offspring at ages 4-6 was the same for both races.
  • The effect of maternal vitamin D status on childhood IQ plateaued at around 40ng/mL, which is near the top of what is considered an adequate level of 25-hydroxyvitamin D.

The authors of the study concluded: “Gestational vitamin D concentrations were positively associated with IQ at age 4-6, suggesting that vitamin D plays an important role in programming neurocognitive development. Vitamin D status may be an important modifiable factor that can be optimized through appropriate nutritional recommendations and guidance. Vitamin D deficiency was especially prevalent among Black women in this cohort, suggesting a higher need for screening and nutritional intervention in this vulnerable population.”

The authors went on to say: “Vitamin D supplementation may be indicated for women who have poor dietary intake of vitamin D and/or reduced cutaneous synthesis related to skin pigmentation [Simply put, sunlight can catalyze the synthesis of vitamin D in our skin, but skin pigmentation filters out the sunlight and decreases vitamin D synthesis.]…”

The Importance Of Vitamin D During Pregnancy

vitamin dLet me put this study in perspective by first discussing the pros and cons of the study. Then I will close with what I think is the most important takeaway from the study.

The Cons Of The Study:

The cons are obvious:

  1. This study shows that a 10 ng/mL increase in 25-hydroxyvitamin D during pregnancy is associated with about a 1-point increase in IQ on a 100-point scale? Is that significant? Probably not, especially when you consider all the other dietary and environmental factors that influence intelligence and educational attainment.

2) We don’t know whether this effect of vitamin D status during pregnancy on IQ will persist as the children grow up. It is more likely that socioeconomic and family factors during childhood will play a much larger role in educational attainment.

The Pros Of The Study:

  1. This study is superior to most previous studies on this topic because of its size and duration. It is also a well-designed study.

2) The authors pointed out a previous study has reported that for each decrease of one IQ point:

    • Lifetime income for men decreases by 1.93%.
    • Lifetime income for women decreases by 3.23%.

3) The effect of vitamin D status during pregnancy on IQ at age 4-6 plateaued at 40 ng/mL. That means the women in this study would obtain optimal benefit by increasing their 25-hydroxyvitamin D levels by 20 ng/mL. Since each 10 ng/mL increase in 25-hydroxyvitamin D during pregnancy increased IQ by 1.17, this would translate into:

  • A 4.5% increase in lifetime earnings for men.
  • A 7.6% increase in lifetime earnings for women.
  • When you look at it this way, the effect of vitamin D during pregnancy on IQ seems a bit more significant.

The Most Important Takeaway From This Study:

  • Of all the things you can do during pregnancy to give your kids an advantage in today’s competitive world, supplementation with vitamin D before and during pregnancy is probably the simplest, cheapest, and safest option available to you.
  • Even if optimizing 25-hydroxyvitamin D levels during pregnancy has no long-term effect on your child’s IQ, we know it has many other benefits for your health and your child’s health.
  • And, as long as you don’t exceed 50 ng/mL of 25-hydroxyvitamin D, it is perfectly safe.

The authors had this to say about supplementation with vitamin D before and during pregnancy: “Popular prenatal supplements, which typically contain 400-600 IU vitamin D, are likely insufficient to correct 25-hydroxyvitamin D deficiencies. Randomized controlled trials have suggested that daily supplementation of 800 to 1,000 may be needed during pregnancy, and that doses of 4,000 IU may be ideal in cases of severe deficiency.”

The Bottom Line

A recent study looked at 25-hydroxyvitamin D status during the second trimester of pregnancy and the IQ of the offspring at ages 4-6. The study found:

  • The average blood level of 25-hydroxyvitamin D at week 23 of pregnancy was 21.6 ng/mL.
    • 6% of the women were vitamin D deficient (<20 ng/mL 25-hydroxyvitamin D).
    • After adjusting for other variables known to affect IQ, every 10ng/mL increase in 25-hydroxyvitamin D status during pregnancy resulted in an increase of 1.17 points in overall IQ.
  • The effect of maternal vitamin D status on childhood IQ plateaued at around 40ng/mL, which is near the top of what is considered an adequate level of 25-hydroxyvitamin D.

The authors of the study concluded: “Gestational vitamin D concentrations were positively associated with IQ at age 4-6, suggesting that vitamin D plays an important role in programming neurocognitive development. Vitamin D status may be an important modifiable factor that can be optimized through appropriate nutritional recommendations and guidance…”

The authors went on to say: “Vitamin D supplementation may be indicated for women who have poor dietary intake of vitamin D and/or reduced cutaneous synthesis related to skin pigmentation…”

In terms of supplementation, the authors said: “Popular prenatal supplements, which typically contain 400-600 IU vitamin D, are likely insufficient to correct 25-hydroxyvitamin D deficiencies. Randomized controlled trials have suggested that daily supplementation of 800 to 1,000 may be needed during pregnancy, and that doses of 4,000 IU may be ideal in cases of severe deficiency.”

For more details and my perspective of the study, read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease.

What Do The US Dietary Guidelines Say About Supplementation?

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What Do The US Dietary Guidelines Say About Your Diet?

Author: Dr. Stephen Chaney

US Dietary Guidelines 2020-2025Science is always changing, and nutritional science is no different. As we learn more, our concept of the “ideal diet” is constantly evolving. Because of that, the USDA and the US Department of Health & Human Services produce a new set of Dietary Guidelines for Americans every 5 years.

The 2020-2025 Dietary Guidelines for Americans have just been released. As usual, the process started with a panel of 20 internationally recognized scientists who produced a comprehensive report on the current state of nutritional science and made recommendations for updated dietary guidelines. After a period of public comment, the dietary guidelines were published.

There were two new features of the 2020-2025 Guidelines:

  • They provided dietary guidelines for every life stage from 6 months of life to adults over 60.
  • The guidelines also addressed personal preferences, cultural traditions, and budgetary concerns in so that each of us can develop a healthy diet that fits our lifestyle.

What Do The US Dietary Guidelines Say About Your Diet?

Here are the 2020-2025 Guidelines in a nutshell:healthy foods

  • Follow a healthy dietary pattern at every life stage.
  • Customize and enjoy nutrient-dense food and beverage choices to reflect personal preferences, cultural traditions, and budgetary considerations.
  • Focus on meeting food group needs with nutrient-dense foods and beverages and stay within calorie limits. They went on to say, “A healthy dietary pattern consists of nutrient-dense forms of foods and beverages across all food groups [emphasis mine], in recommended amounts, and within calorie limits.”

They said, “the core elements that make up a healthy dietary pattern include:”

    • Vegetables of all types – dark green, red, and orange vegetables; beans, peas, and lentils; starchy vegetables; and other vegetables.
    • Fruits – especially whole fruits.
    • Grains – at least half of which are whole.
    • Dairy – including fat-free or low-fat milk, yogurt, and cheese; lactose-free versions; and fortified soy beverages and soy yogurt as alternatives. [Other plant-based milk and yogurt foods were not recommended because they do not provide as much protein as dairy. So, they were not considered equivalent foods.]
    • Protein foods – including lean meats, poultry, and eggs; seafood; beans, peas, and lentils; and nuts, seeds, and soy products.
    • Oils – including vegetable oils and oils in food, such as seafood and nuts.
  • Limit foods and beverages higher in added sugars, saturated fat, and sodium; and limit No Fast Foodalcoholic beverages. Their specific recommendations are:
    • Added sugars – less than 10% of calories/day starting at age 2. Avoid foods and beverages with added sugars for those younger than 2.
    • Saturated fat – Less than 10% of calories starting at age 2.
    • Sodium – Less than 2,300 mg per day – even less for children younger than 14.
    • Alcoholic beverages – Adults of legal drinking age can choose not to drink, or to drink in moderation by limiting intake to 2 drinks or less in a day for men and 1 drink or less in a day for women, when alcohol is consumed. Drinking less is better for health than drinking more. There are some adults who should not drink alcohol, such as women who are pregnant.

For more details, read the 2020-2025 Dietary Guidelines for Americans.

The Dark Side Of The US Dietary Guidelines

Darth VaderThe US Dietary Guidelines point Americans in the right direction, but they are never as strong as most nutrition experts would like. The 2025 Dietary Guidelines are no exception. They have two major limitations:

#1: The food industry has watered down the guidelines. This happens every time a new set of guidelines are released. The food and beverage lobbies provide their input during the public comment period. And because they fund a significant portion of USDA research, their input carries a lot of weight. Here are the 3 places where they altered the recommendations of the scientific panel:

  • The scientific panel recommended that Americans decrease the intake of added sugar from 13% of daily calories to 6%. The final dietary guidelines recommended reducing sugar to 10% of daily calories.
  • The scientific panel recommended that both men and women limit alcoholic drinks to one a day. The final dietary guidelines recommended men limit alcoholic drinks to two a day.
  • The scientific panel included these statements in their report:
    • “Dietary patterns characterized by higher intake of red and processed meats, sugar-sweetened foods and beverages, and refined grains are…associated with detrimental health outcomes.”
    • “Replacing processed or high fat-meats…with seafood could help lower intake of saturated fat and sodium, nutrients that are often consumed in excess of recommended limits.”
    • “Replacing processed or high-fat meats with beans, peas, and lentils would have similar benefits.”

These statements are included in the final report, but they are buried in portions of the report that most people are unlikely to read. The summary that most people will read recommends shifts in protein consumption to “add variety” to the diet.

#2: The guidelines do not address sustainability and do not explicitly promote a shift to more Planetary Dietplant-based diets. Again, this was based on input from food lobby groups who argued that sustainability has nothing to do with nutrition.

If you are concerned about climate change and the degradation of our environment caused by our current farming practices, this is a significant omission.

I have covered this topic in a recent issue of “Health Tips From the Professor”. Here is a brief summary:

  • In 2019 a panel of international scientists was asked to conduct a comprehensive study on our diet and its effect on both our health and our environment.
  • The scientific panel carefully evaluated diet and food production methods and asked three questions:
    • Are they good for us?
    • Are they good for the planet?
    • Are they sustainable? Will they be able to meet the needs of the projected population of 10 billion people in 2050 without degrading our environment.
  • They developed dietary recommendations popularly known as the “Planetary Diet”. Here are the characteristics of the planetary diet.
    • It starts with a vegetarian diet. Vegetables, fruits, beans, nuts, soy foods, and whole grains are the foundation of the diet.
    • It allows the option of adding one serving of dairy a day.
    • It allows the option of adding one 3 oz serving of fish or poultry or one egg per day.
    • It allows the option of swapping seafood, poultry, or egg for a 3 oz serving of red meat no more than once a week. If you want a 12 oz steak, that would be no more than once a month.

Unless you are a vegan, this diet is much more restrictive than you are used to. However, if you, like so many Americans believe that climate change is an existential threat, I would draw your attention to one of the concluding statements from the panel’s report.

  • “Reaching the Paris Agreement of limiting global warming…is not possible by only decarbonizing the global energy systems. Transformation to healthy diets from sustainable food systems is essential to achieving the Paris Agreement.”

In other words, we can do everything else right, but if we fail to change our diet, we cannot avoid catastrophic global warming.

What Do The US Dietary Guidelines Say About Supplementation?

MultivitaminsThe authors of the 2020-2025 US Dietary Guidelines have relatively little to say about supplementation. However:

  • They list nutrients that are of “public health concern” for each age group. Nutrients of public health concern are nutrients that:
    • Are underconsumed in the American diet.
    • Are associated with health concerns when their intake is low.
  • They state that “dietary supplements may be useful in providing one or more nutrients that otherwise might be consumed in less than recommended amounts.”
  • They recommend specific supplements for several age groups.

Here are their nutrients of public health concern and recommended supplements for each age group:

#1: General population.

  • Nutrients of public health concern are calcium, dietary fiber, and vitamin D. They state that supplementation may be useful for meeting these needs.

#2: Breast Fed Infants.

  • Supplementation with 400 IU/day of vitamin D is recommended shortly after birth.

#3: Vegetarian Toddlers.

  • Iron and vitamin B12 are nutrients of concern.

#4: Children & Adolescents.

  • Calcium and vitamin D are nutrients of concern. Dairy and/or fortified soy alternatives are recommended to help meet these needs.
  • Iron, folate, vitamin B6, vitamin B12, and magnesium are also nutrients of concern for adolescent females.

#5: Adults (Ages 19-59).

  • 30% of men and 60% of women do not consume enough calcium and 90% of both men and women do not get enough vitamin D.

#6: Pregnant & Lactating Women:

  • Calcium, vitamin D, and fiber are nutrients of concern for all women in this age group.
  • In addition, women who are pregnant have special needs for folate/folic acid, iron, iodine, and vitamin D.
  • Women who are pregnant or thinking of becoming pregnant should take a daily prenatal vitamin and mineral supplement to meet folate/folic acid, iron, iodine, and vitamin D needs during pregnancy. They go on to say that many prenatal supplements do not contain iodine, so it is important to read the label.
  • All women who are planning or capable of pregnancy should take a daily supplement containing 400 to 800 mcg of folic acid.

#7: Older Adults (≥ 60).

  • Nutrients of concern for this age group include calcium, vitamin D, fiber, protein, and vitamin B12.
  • About 50% of women and 30% of men in this age group do not get enough protein in their diet.

My Perspective:

The US Dietary Guidelines use foods of public health concern as the only basis for recommending Supplementation Perspectivesupplementation. I prefer a more holistic approach that includes increased needs, genetic predisposition, and preexisting diseases as part of the equation (see the diagram on the right). I have discussed this concept in depth in a previous issue of “Health Tips From The Professor”.

I have also taken this concept and made supplement recommendations for various health goals in a free eBook called “Your Design For Healthy Living”.

Some people may feel I should have included more supplements in my recommendations. Others may feel I should have included fewer supplements in my recommendations. No list pf recommend supplements is perfect, but I have tried to include those supplements supported by good scientific evidence in my recommendations.

The Bottom Line 

The USDA and Department of Health & Human Services have just released the 2020-2025 US Dietary Guideline. In the article above I have summarized:

  • Their recommendations for a healthy diet.
  • Their recommendations for supplementation.
  • The dark side of the US Dietary Guidelines.

For more details, read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease.

Does Vitamin D Prevent Depression?

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Why You Can’t Believe Everything You Read

depressionThe days are getting shorter and Seasonal Depression, often called the “winter blues”, will soon be upon us. Most of the research on Seasonal Depression has centered on the effect of sunlight on our hormones.

However, sunlight is also responsible for the synthesis of vitamin D in our skin cells. So, some experts have hypothesized that low levels of 25-hydroxyvitamin D, the active form of vitamin D, in our blood also play a role in the winter blues.

If so, that could have important implications for managing depression, especially in older adults. Depression is estimated to affect around 6.5 million of the 49 million adults over the age of 65 in our country. Treatment costs for older adults in this country are estimated at $9 billion/year.

If something as simple and inexpensive as a vitamin D supplement could reduce the risk of depression, it would be a huge boon to our health care system.

Association studies suggest that may be a possibility. For example, one recent meta-analysis of 6 clinical studies (H Li et al, The American Journal of Geriatric Psychiatry, 27: P1192-1202, 2019) reported that every 10 ng/mL increase in 25-hydroxyvitamin D was associated with a 12% decrease in the risk of depression in older adults.

However, association studies do not prove cause and effect.

Unfortunately, randomized, placebo controlled clinical trials have given mixed results. A few studies suggested that vitamin D might reduce depression risk, but most of the studies found no effect of vitamin D on depression risk. However, most of the published studies have been poorly designed They were too small, too short, or did not use validated methods for measuring depression.

This was the genesis of the current study (OI Okerke et al., JAMA, 324: 471-480, 2020). It was designed to be a definitive study that would avoid the defects of previous studies.

The study concluded that vitamin D supplementation does not decrease the risk of depression in older adults, and those were the headlines you have probably seen. But is that conclusion true? Let’s take a peek behind the curtain and analyze the study.

How Was The Study Done?

Clinical StudyThis study was an offshoot of the VITAL (VITamin D and OmegaA-3 TriaL) clinical study, so let me start by describing the characteristics of that study.

The VITAL study (JE Manson et al, New England Journal of Medicine, DOI: 10.1056/NEJMoa1811403) enrolled 25,871 healthy adults (average age = 67) in the United States. The study participants were 50% female, 50% male, and 20% African American. None of the participants had preexisting cancer or heart disease.

Study participants were given questionnaires on enrollment to assess clinical and lifestyle factors including dietary intake. Blood samples were taken from about 65% of the participants to determine 25-hydroxyvitamin D levels (a measure of vitamin D status) at baseline and at the end of the first year to assess the effectiveness of vitamin D supplementation. The participants were given either 2,000 IU of vitamin D/day or a placebo and followed for an average of 5.3 years.

This study consisted of 18,353 participants from the VITAL study. Ninety percent of the participants had no previous history of depression. Ten percent had previously been diagnosed or treated for depression but had been depression-free for over 2 years.

The participants filled out annual questionnaires to quantify the onset of depression by three criteria:

  • A diagnosis of depression by a physician.
  • Treatment for depression (medications, counseling, or both).
  • A questionnaire designed to evaluate symptoms of depression. The authors of the study referred to this as an assessment of their mood.

During the 5.3 year follow up period 3.6% of the participants reported the onset of diagnosed depression or a mood consistent with depression. This is consistent with previous studies showing that 1-5% of healthy, non-institutionalized older adults suffer from depression.

Does Vitamin D Prevent Depression?

thumbs down symbolThe results of the study were clear.

Treatment with 2,000 IU of vitamin D3 compared to placebo for 5.3 years did not have a statistically significant effect on:

  • The incidence or recurrence of depression diagnosis, or…
  • Treatment for depression, or…
  • Clinically relevant depressive symptoms.

The authors concluded, “These findings do not support the use of vitamin D3 in adults to prevent depression.”

Why You Can’t Believe Everything You Read

It would be tempting to say, “Case closed. We now know for certain that vitamin D has no effect on depression.”

After all, this was an excellent study. It was large (18,353 participants), lasted a long time (5.3 years), and used well established measures of depression. What’s not to like?

Peek Behind The CurtainUnfortunately, even well-designed studies can give misleading results. Let’s take a peek behind the curtain and see where this study went astray.

There were two glaring deficiencies in this study.

#1: Most of the participants had adequate vitamin D status at the beginning of the study. The average 25-hydroxyvitamin D level of participants at the beginning of the study was 31 ng/mL (78 nmol/L). The NIH considers 20-50 ng/mL (50-125 nmol/L) to be an adequate level of 25-hydroxyvitamin D for most physiological functions. This means that study participants started in the middle of the adequate range with respect to vitamin D status.

This was not a failure of study design. In fact, the authors of the study are to be commended for measuring the vitamin D status of participants at the beginning of the study. Many previous studies have neglected to do that.

The problem is that vitamin D has become extremely popular. Many Americans are already taking multivitamins or vitamin D supplements. To recruit enough people for the study the authors were forced to allow participants to enter the study even if they were taking vitamin D supplements, as long as the amount did not exceed 800 IU/day.

In short, most of the participants in this study were already supplementing with up to 800 IU/day of vitamin D. If so, they were allowed to continue taking their vitamin D supplements. The 2,000 IU of vitamin D was added to what they were already taking.

The question then becomes, if people are already taking RDA levels of supplemental vitamin D and their blood levels of 25-hydroxyvitamin D are already in the adequate range, do we really expect additional supplemental vitamin D to have a beneficial effect?

The author’s answer to that question was, “The mean baseline 25-hydroxyvitamin D level was 30.8 ng/mL; this value is already at a threshold for extraskeletal health benefits [health benefits other than bone health], and so the ability to observe effects of vitamin D3 supplementation may have been attenuated. [To determine whether vitamin D supplementation reduces the risk of depression] large-scale studies would be required to address the effects of high-dose, long-term vitamin D3 supplementation among those with nutrient deficiency.”

My more direct answer would be, “This study provides no useful information on whether vitamin D3 supplementation reduces the risk of depression. What is needed are studies that start with a population that is deficient in vitamin D.”

An accurate conclusion from this study would have been, “If you are already taking vitamin D supplements and/or have an adequate vitamin D status, supplementation with an extra 2,000 IU of vitamin D3 provides no additional benefit with respect to the risk of developing depression.” But that is not what the headlines said.

#2: The study did not record the reason for the onset of depression. That is important because the top 3 causes of depression in adults 65 and older are:

  • Loss of a spouse or partner.
  • Chronic health issues.
  • Restricted blood flow to the brain.

It is unlikely that vitamin D supplementation would have much of an effect on these issues.

In contrast, seasonal depression, which is more likely to be affected by vitamin D supplementation, was not measured in this study.

The Bottom Line

You may have seen recent headlines saying that vitamin D supplementation has no effect on the risk of developing depression.

The study behind these headlines was a very well-designed study. It was large (18,353 participants), lasted a long time (5.3 years), and used well established measures of depression.

It would be tempting to say, “Case closed. We now know for certain that vitamin D supplementation has no effect on depression.”

Unfortunately, even well-designed studies can give misleading results. This one had a major flaw that made the data almost useless.

The problem is that most Americans are already taking multivitamins or vitamin D supplements. To recruit enough people for the study the authors were forced to allow participants to enter the study even if they were taking vitamin D supplements, as long as the amount did not exceed 800 IU/day.

That meant that most participants already had adequate blood levels of 25-hydroxyvitamin D at the beginning of the study.

The question then becomes, if people are already taking RDA levels of supplemental vitamin D and their blood levels of 25-hydroxyvitamin D are already in the adequate range, do we really expect additional supplemental vitamin D to have a beneficial effect? The answer is, “Probably not”.

Rather than saying that this study definitively shows that vitamin D supplementation has no effect on the risk of developing depression, I feel it would be more accurate to say, “This study provides no useful information on whether vitamin D3 supplementation reduces the risk of depression. What is needed are studies that start with a population that is deficient in vitamin D.”

An accurate conclusion from this study would have been, “If you are already taking vitamin D supplements and/or have an adequate vitamin D status, supplementation with an extra 2,000 IU of vitamin D3 provides no additional benefit with respect to the risk of developing depression.” But that is not what the headlines said.

For more details, read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease.

The Truth About Vitamin D And Respiratory Diseases

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How Should You Prepare For This Winter?

deadSome health experts are making dire predictions for this fall when COVID-19 overlaps with our annual flu season. People are worried.

When people are worried, hucksters smell a quick buck and start coming out of the woodworks. They are touting all sorts of miracle pills and potions that will keep us safe this winter. The FDA is doing its best to shut them down, but it’s like the “Whack A Mole” game you may remember from the county fair. As soon as the FDA shuts one down, another pops up.

In the meantime, you are left trying to sort through the claims. I could write a whole book on the truth (and lies) about the claims you are seeing on the internet. But this week I will focus on vitamin D. I will give you unbiased answers to three questions.

1) What is the truth about vitamin D and respiratory disease?

2) Will vitamin D help protect you against COVID-19?

3) How should you prepare for this winter?

I am basing today’s “Health Tip” on a recently published study (H Brenner et al, Nutrients 2020, 12, 2488) looking at the effect of vitamin D status on deaths from respiratory disease in older German adults.

How Was The Study Done?

Clinical StudyThe data from this study were taken from an ongoing study in Germany looking at the effect of diet and lifestyle on health outcomes in older adults. In this case, 9548 adults, ages 50-75, from the region of Saarland in Germany were enrolled in the study between 2000 and 2002 and followed for an average of 15 years.

Blood samples were drawn at the time of enrollment and 25-hydroxyvitamin D levels were determined as a measure of vitamin D status. Deaths and cause of deaths over the 15 year period were obtain from German health records.

The basic characteristics of the study population were:

  • The gender breakdown was 43.8% men, 52.6% female.
  • The average age was 62.1 years.
  • Almost all participants were Caucasians of German or French descent.
  • 8% were vitamin D insufficient (25-hydroxyvitamin D of 30-<50 nmol/L)
  • 1% were vitamin D deficient (25-hydroxyvitamin D of <30 nmol/L)

Note: Almost 60% of this study group had an inadequate vitamin D status. The comparable figures for the US population are 42% with inadequate vitamin D status (34% vitamin D insufficient and 8% vitamin D deficient).

The reasons for this are likely two-fold:

  • Saarland is at the latitude of Newfoundland, Canada, so sun exposure is less than for most Americans.
  • Germans are less likely to consume supplements than Americans.

However, the fact that 60% of this study group has inadequate vitamin D status makes it a particularly good group to look at the effect of vitamin D status on health outcomes.

The Truth About Vitamin D And Respiratory Diseases

the truth signThis study found:

  • Vitamin D insufficiency (25-hydroxyvitamin D of 30-<50 nmol/L) increased the risk of dying from respiratory disease by 1.9-fold for men and 2.1-fold for women.
  • Vitamin D deficiency (25-hydroxyvitamin D of <30 nmol/L) increased the risk of dying from respiratory disease by 2.3-fold for men and 3.0-fold for women.

The authors pointed out that this was consistent with a recent meta-analysis of randomized clinical trials showing that supplementation with RDA levels of vitamin D reduced the risk of acute respiratory tract infections by 70% in people who were vitamin D deficient.

The authors concluded:

“Vitamin D insufficiency and deficiency are common and account for a large proportion of respiratory disease mortality in older adults…Our results, along with evidence from meta-analyses from RCTs [Randomized Placebo-Controlled Clinical Trials] regarding results of vitamin D3 supplementation on various outcomes, suggest that vitamin D3 supplementation could contribute to lowering mortality from respiratory and other diseases during and beyond the COVID-19 pandemic, particularly among women.”

How Should You Prepare For This Winter?

Winter WindNow it is time to answer the three questions I posed at the beginning of this article:

1) What is the truth about vitamin D and respiratory disease?

There have been many studies suggesting that inadequate vitamin D status increases the risk of “catching” respiratory diseases such as the seasonal flu. Some of those studies showed that supplementation with vitamin D3 reduced the risk of catching respiratory diseases. However, most of those were small studies.

This study and the meta-analysis the authors referred to were much larger, better designed studies. Other large, well designed studies are needed. But, taken together, these two studies strongly support the hypothesis that inadequate vitamin D status significantly increases the risk of developing and dying from respiratory diseases.

However, we do need to put this into perspective.

  • Supplementation with vitamin D primarily protects individuals with inadequate vitamin D status. It doesn’t appear to offer significant benefit for individuals with adequate vitamin D status (>50 nmol/L 25-hydroxyvitamin D).
  • Supplementation with vitamin D at doses of 2,000 IU or less appears to be sufficient for most people. There is little evidence that megadoses are beneficial unless you are severely vitamin D deficient (more about that below).

2) Will vitamin D help protect you against COVID-19?

vitamin dThe answer to this question is less clear. As we learn more about COVID-19 we have learned that it is much more than just a respiratory disease. On the other hand, cellular studies suggest that vitamin D may interfere with the mechanism by which COVID-19 attacks cells.

What do clinical studies say? We are just learning. Four small clinical trials and one large study have recently been published or posted online as preprints prior to being accepted for publication.

  • The second study (HW Kaufman et al, PLOS One, September 17, 2020) used data from a major national testing center (Quest Diagnostics) and linked COVID-19 test results with 25-hydroxyvitamin D test results for 191,779 patients. This study reported that vitamin D deficiency was associated with a 30% increased risk of testing positive for COVID-19.
  • The third study found that vitamin D deficiency was associated with hospital admissions for COVID-19.
  • The fourth study found that vitamin D deficiency was associated ICU admissions for COVID-19.

Taken together these 5 studies suggest that vitamin D deficiency may increase the risk of being infected by COVID-19 and on the severity of the disease if you are infected.

I should point out that these studies are preliminary. Normally we would say that they need to be confirmed by larger studies before becoming incorporated into the standard of care for COVID-19.

You might be saying to yourself, , “Why is the medical community paying so much attention to preliminary studies?” The answer is simple:

  • The need is urgent. We need all the tools at our disposal to fight this deadly disease, and we need them now.
  • Vitamin D3 supplementation at 2,000 IU or less is inexpensive and safe. Plus, even if further studies find that our vitamin D status has no effect on COVID-19 risk, we know that adequate vitamin D has many other potential health benefits.

To summarize:

  • Preliminary studies suggest that adequate vitamin D status may offer some protection for COVID-19. These studies are not definitive. No reputable scientist is ready to tell you that vitamin D will ward off COVID-19. However, supplementation with 2000 IU/day or less of vitamin D3 is safe and may have multiple health benefits.
  • Vitamin D should not be considered a “magic bullet”. It is just one aspect of a holistic approach to creating a healthy body that is less susceptible to respiratory diseases like COVID-19.

3) How Should You Prepare For This Winter?

Winter WindAs we approach the winter months, the days are getting shorter and sun exposure is decreasing. This is the time of year when your 25-hydroxyvitamin D levels will be at their lowest.

At the same time, we are likely to see a convergence of the seasonal flu, flu-like illnesses, and COVID-19 this winter. You will need a healthy body, a healthy immune system, and adequate vitamin D status more than ever.

When asked about vitamin D and COVID-19 in a recent interview, Dr. Anthony Fauci, Director of the National Institute of Allergy and Infectious Diseases, said, “If you’re deficient in vitamin D, that does have an impact on your susceptibility to infection. I would not mind recommending, and I do it myself, taking vitamin D supplements.”

I recommend supplementation with vitamin D3 to make sure your vitamin D status is adequate. The RDA for vitamin D is 600 IU for adults and 800 IU for seniors over the age of 70. However, because the efficiency with which we convert vitamin D3 to 25-hydroxyvitamin D varies from person to person, many experts recommend supplementing with 1,500-2,000 IU of vitamin D3.

I also recommend that you ask your health provider for a 25-hydroxyvitamin D test. If you are in the vitamin D deficient range, your health provider may recommend more than 2,000 IU/day of vitamin D3.

Finally, we should not rely on vitamin D alone. As I discussed in a previous issue of “Health Tips From The Professor”, I recommend a holistic approach for strengthening our immune systems, and I recommend the CDC guidelines for reducing the risk of catching both the flu and COVID-19.

I would note that social distancing, hand washing, and mask wearing are just as effective at reducing the risk of getting the flu as they are for getting COVID-19. In fact, some Asian countries practice mask wearing in public every flu season.

The Bottom Line

  • A recent study found that inadequate vitamin D status caused a 2-3-fold increased risk of dying from respiratory illnesses for seniors (ages 50-74).
  • A previous meta-analysis reported that supplementation with RDA levels of vitamin D reduced the risk of acute respiratory tract infections by 70% in people who were vitamin D deficient.
  • Taken together, these two studies strongly support the hypothesis that inadequate vitamin D status significantly increases the risk of developing and dying from respiratory diseases.
  • Preliminary studies suggest that adequate vitamin D status may offer some protection for COVID-19. These studies are not definitive. No reputable scientist is ready to tell you that vitamin D will ward off COVID-19. However, supplementation with 2000 IU/day or less of vitamin D3 is safe and may have multiple health benefits.
  • Vitamin D should not be considered a “magic bullet”. It just one aspect of a holistic approach to creating a healthy body that is less susceptible to respiratory diseases like COVID-19.

So, how should we prepare for this winter?

  • As we approach the winter months, the days are getting shorter and sun exposure is decreasing. This is the time of year when your 25-hydroxyvitamin D levels will be at their lowest.
  • At the same time, we are likely to see a convergence of the seasonal flu, flu-like illnesses, and COVID-19 this winter. You will need a healthy body, a healthy immune system, and adequate vitamin D status more than ever.
  • I recommend supplementation with vitamin D3 to make sure your vitamin D status is adequate. The RDA for vitamin D is 600 IU for adults and 800 IU for seniors over the age of 70. However, because the efficiency with which we convert vitamin D3 to 25-hydroxyvitamin D varies from person to person, many experts recommend supplementing with 1,500-2,000 IU of vitamin D3.
  • Finally, we should not rely on vitamin D alone. As I discussed in a previous issue of “Health Tips From The Professor”, I recommend a holistic approach for strengthening our immune systems, and I recommend the CDC guidelines for reducing the risk of catching both the flu and COVID-19.

I would note that social distancing, hand washing, and mask wearing are just as effective at reducing the risk of getting the flu as they are for getting COVID-19. In fact, some Asian countries practice mask wearing in public every flu season.

For more details, read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease.

Does Poverty Affect Nutritional Status?

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How Can We Improve Nutrition In Disadvantaged Communities?

Calcium FoodsRecently there has been increased focus on health disparities in disadvantaged communities. In our discussions of the cause of these health disparities, two questions seem to be ignored.

1. Does poverty play a role in poor nutrition?

2. Does poor nutrition play a role in the health disparities we see in disadvantaged communities?

The study (K Marshall et al, PLoS One 15(7):e0235042) I discuss in this week’s “Health Tips From The Professor” attempts to address both of these questions.

Before, I start, let me put this study into context.

  • Osteoporosis is a major health problem in this country. Over 2 million osteoporosis-related fractures occur each year, and they cost our health care system over 19 billion dollars a year. Even worse, for many Americans these osteoporosis-related fractures often cause:
    • A permanent reduction in quality of life.
    • Immobility, which can lead to premature death.
  • Inadequate calcium and vitamin D intakes increase the risk of osteoporosis.

While most studies simply report calcium and vitamin D intakes for the general population, this study breaks them down according to ethnicity and income levels. The results were revealing.

How Was The Study Done?

Clinical StudyThis study drew on data from the 2007-2010 and 2013-2014 National Health and Nutrition Examination Surveys (NHANES). These surveys are conducted by the National Center for Health Statistics, which is part of the CDC. They are designed to assess the health and nutritional status of adults and children in the United States and are used to produce health statistics for the nation.

The NHANES interview includes demographic, socioeconomic, dietary, and health-related questions. The examination component consists of medical, dental, and physiological measurements, as well as laboratory tests administered by highly trained medical personnel. All participants visit a physician. Dietary interviews and body measurements are included for everyone.

This study measured calcium intake, vitamin D intake, and osteoporosis for adults 50 and older. The data were separated by gender, ethnic group and income level. Four different measures of poverty were used. For purposes of simplicity, I will only use one of them, income beneath $20,000, for this article.

Does Poverty Affect Nutritional Status?

The Effect of Ethnicity And Gender On Calcium And Vitamin D Intake: 

FriendsWhen the authors looked at the effect of ethnicity and gender on calcium and vitamin D intake, in people aged 50 and older the results were (Note: I am using the same ethnic nomenclature used in the article):

Hispanics:

    • 66% (75% for women and 56% for men) were getting inadequate calcium intake.
    • 47% (47% for women and 47% for men) were getting inadequate vitamin D intake.

Non-Hispanic Blacks:

    • 75% (83% for women and 64% for men) were getting inadequate calcium intake.
    • 53% (51% for women and 54% for men) were getting inadequate vitamin D intake.

Non-Hispanic Whites:

    • 60% (64% for women and 49% for men) were getting inadequate calcium intake.
    • 33% (30% for women and 37% for men) were getting inadequate vitamin D intake.

For simplicity, we can generalize these data by saying:

Gender:

    • Women are more likely to be calcium-deficient than men.
    • Men are more likely to be vitamin D-deficient than women.

Ethnicity: For both genders and for both calcium and vitamin D:

    • The rank order for deficiency is Non-Hispanic Blacks > Hispanics > Non-Hispanic Whites.

The Effect Of Poverty On Calcium Intake, Vitamin D Intake, And Osteoporosis:

PovertyWhen looking at the effect of poverty, the authors asked to what extent poverty (defined as income below $20,000/year) increased the risk of calcium and vitamin D deficiency in adults over 50. Here is a summary of the data

Hispanics:

    • For both Hispanic women and Hispanic men, poverty had little effect on the risk of calcium and vitamin D deficiency.

Non-Hispanic Blacks:

    • For Non-Hispanic Black women, poverty had little effect on the risk of calcium deficiency, and vitamin D deficiency.
    • For Non-Hispanic Black men, poverty increased the risk of both calcium and vitamin D deficiency by 32%.

Non-Hispanic Whites:

    • For Non-Hispanic White women, poverty had little effect on the risk of calcium deficiency but increased the risk of vitamin D deficiency by 30%.
    • For Non-Hispanic White men, poverty increased the risk of both calcium deficiency and vitamin D deficiency by 18%.

For simplicity, we can generalize these data by saying:

    • Poverty increased the risk of both calcium and vitamin D deficiency for Non-Hispanic Black men, Non-Hispanic White women, and Non-Hispanic White men.

Other statistics of interest:

  • The SNAP program (formerly known as Food Stamps) had little effect on calcium and vitamin D intake. There are probably two reasons for this:
    • In the words of the authors, “While the SNAP program has been shown to decrease levels of food insecurity, the quality of the food consumed by SNAP participants does not meet the standards for a healthy diet.” In other words, the SNAP program ensures that participants have enough to eat, but SNAP participants are just as likely to prefer junk and convenience foods as the rest of the American population. The SNAP program provides no incentive to eat healthy foods.
    • We also need to remember that dairy foods are a major source of calcium and vitamin D in the American diet and that Hispanics and Non-Hispanic Blacks are more likely to be lactose-intolerant than the rest of the American population. There are other sources of calcium and vitamin D in the American diet. But without some nutrition education, most Americans are unaware of what they are.
  • An increased risk of osteoporosis was found in Non-Hispanic Black men, and Non-Hispanic Whites with incomes below $20,000/year.
    • This increased risk of osteoporosis was seen primarily for the individuals in each group who were deficient in calcium and vitamin D. There were other factors involved, but I will focus primarily on the effect of poverty on calcium and vitamin D intake in the discussion below.

How Can We Improve Nutrition In Disadvantaged Communities?

Questioning WomanLet’s start with the two questions I posed at the beginning of this article:

1. Does poverty play a role in poor nutrition?

2. Does poor nutrition play a role in the health disparities we see in disadvantaged communities?

In terms of calcium intake, vitamin D intake, and the risk of osteoporosis, the answer to both questions appears to be, “Yes”. So, the question becomes, “What can we do?”

It is when we start to ask what we can do to increase calcium and vitamin D intake and decreased the risk of osteoporosis in disadvantaged communities that we realize the complexity of the problem. There are no easy answers. Let’s look at some of the possibilities.

[Note: I am focusing on what we can do to prevent osteoporosis, not to detect or treat osteoporosis. The solutions for those issues would be slightly different.]

1. We could increase funding for SNAP. That would increase the quantity of food available for low income families, but, as noted above, would do little to improve the quality of the food eaten.

2. We could improve access to health care in disadvantaged communities. But unless physicians started asking their patients what they eat and start recommending a calcium and vitamin D supplement when appropriate, this would also have little impact on diet quality.

3. We could improve nutrition education. A colleague of mine in the UNC School of Public Health ran a successful program of nutrition education through churches and community centers in disadvantaged communities for many years. The program taught people how to eat healthy on a limited budget. Her program improved the health of many people in disadvantaged communities.

However, the program was funded through grants. When she retired, federal and state money to support the program eventually dried up. The program she started is a model for what we should be doing.

4. The authors suggested food fortification as a solution. In essence, they were suggesting that junk and convenience foods be fortified with calcium and vitamin D. That might help, but I don’t think it is a good idea.

If we want to improve the overall health of disadvantaged communities, we need to find ways to replace junk and convenience foods with healthier foods. Adding a few extra nutrients to unhealthy foods does not make them healthy.

5. The authors also said that a calcium and vitamin D supplement would be a cheap and convenient way to eliminate calcium and vitamin D deficiencies. Unfortunately, supplements are currently not included in the SNAP program. Unless that is changed, even inexpensive supplements are a difficult choice for families below the poverty line.

As I said at the beginning of this section, there are no easy answers. It is easy to identify the problem. It would be easy to throw money at the problem. But finding workable solutions that could make a real difference are hard to identify.

Yes, we should make sure every American has enough to eat. Yes, we should make sure every American has access to health care. But, if we really want to improve the health of our disadvantaged communities, we also need to:

  • Change the focus of our health care system from treatment of disease to prevention of disease.
  • Train doctors to ask their patients what they eat and to instruct their patients how simple changes in diet could dramatically improve their health.
  • Provide basic nutrition education to disadvantaged communities at places where they gather, like churches and community centers. This would cover topics like eating healthy, shopping healthy on a limited budget, and cooking healthy.

We don’t necessarily need another massive federal program. But those of us with the knowledge could each volunteer to share that knowledge in disadvantaged communities.

  • Cover basic supplements, like multivitamins, calcium and vitamin D supplements, and omega-3 supplements in food assistance programs like SNAP.

The Bottom Line

Osteoporosis is a major health problem in this country. Over 2 million osteoporosis-related fractures occur each year, and they cost our health care system over 19 billion dollars a year. Even worse, for many Americans these osteoporosis-related fractures often cause:

  • A permanent reduction in quality of life.
  • Immobility, which can lead to premature death.

We know that inadequate calcium and vitamin D intakes increase the risk of osteoporosis. But most studies simply report calcium and vitamin D intakes for the general population. At the beginning of this article, I posed two questions.

  1.  Does poverty play a role in poor nutrition?

2. Does poor nutrition play a role in the health disparities we see in disadvantaged communities?

A recent study looked at the effect of gender, ethnicity and income levels on calcium intake, vitamin D intake, and the risk of developing osteoporosis. The results of this study shed some light on those two questions.

When looking at the effect of gender and ethnicity on the risk of inadequate calcium and vitamin D intake, the study found:

  • Women are more likely to be calcium-deficient than men.
  • Men are more likely to be vitamin D-deficient than women.
  • For both genders and for both calcium and vitamin D, the rank order for deficiency is Non-Hispanic Blacks > Hispanics > Non-Hispanic Whites. [Note: Note: I am using the same ethnic nomenclature used in the study.]
  • Poverty (defined as incomes below $25,000/year) significantly increased the risk of both calcium and vitamin D deficiency for Non-Hispanic Black men, Non-Hispanic White women, and Non-Hispanic White men.
  • An increased risk of osteoporosis was also found in Non-Hispanic Black men, and Non-Hispanic White men and women with incomes below $20,000/year.
  • This increased risk of osteoporosis was seen primarily for the individuals in each group who were deficient in calcium and vitamin D.

In short, this study suggests that the answer to both questions I posed at the beginning of the article is, “Yes”.

For more information and a discussion of what we could do to correct this health disparity in disadvantaged communities, read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease.

Does Vitamin D Prevent Type 1 Diabetes?

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Does Genetics Influence Supplementation Benefits?

diabetesThe cause of type 1 diabetes is a mystery. If you go to an authoritarian source like the Mayo Clinic, you will discover that:

  • Type 1 diabetes is an autoimmune disease that selectively attacks the insulin-producing islet cells of the pancreas.
  • Certain genetic variants predispose individuals to type 1 diabetes.
  • The autoimmune response may be triggered by a viral infection or other unknown environmental factors in genetically susceptible individuals.
  • The incidence of type 1 diabetes increases as you travel away from the equator, which suggests that vitamin D may be involved.

The idea that vitamin D may be involved is an important concept because it suggests that vitamin D supplementation might reduce the risk of developing type 1 diabetes. This idea was reinforced by a Finnish study (E Hyponnen et al, Lancet, 358: 1500-1503, 2001) published in 2001 showing the vitamin D supplementation of newborn infants reduced the incidence of type 1 diabetes at age 1.

However, subsequent studies in other parts of the world have had mixed results. Some have confirmed the results of the Finnish study. Others have come up empty.

Similarly, some studies have shown a correlation between low 25-hydroxyvitamin D levels in the blood and the development of type 1 diabetes in children, while other studies have found no correlation.

Why the discrepancy between studies? Some of the differences can be explained by differences in the populations studied or differences in study design. But what if there were another variable that none of the previous studies has considered?

The study (JM Norris et al, Diabetes, 67: 146-154, 2018) I review this week describes just such a variable. The authors of the study hypothesized that the association between 25-hydroxyvitamin D levels and the risk of developing type 1 diabetes is influenced by mutations that affect the way vitamin D works in the body. Previous studies have not taken these mutations into account. If the author’s hypothesis is true, it might explain why these studies have produced conflicting results.

In this article, I will answer 3 questions:

  • Does vitamin D prevent type 1 diabetes?
  • If so, is supplementation with vitamin D important?
  • Who will benefit most from vitamin D supplementation?

But, before I answer those questions, I should begin by providing some background. I will start by reviewing the how diet, increased need, disease, and genetics influence the likelihood that we will benefit from supplementation. Then I will review vitamin D metabolism.

Does Genetics Influence Supplementation Benefits?

need for supplementsThe reason so many studies find no benefit from supplementation is that they are asking the wrong question. They are asking “Does supplementation benefit everyone?” That is an unrealistic expectation.

I have proposed a much more realistic model (shown on the left) for when we should expect supplementation to be beneficial. Simply put, we should ask:

  • Is the diet inadequate with respect to the nutrient that is being studied?
  • Is there an increased need for that nutrient because of age, gender, activity level, or environment?
  • Is there a genetic mutation that affects the metabolism or need for that nutrient?
  • Is there an underlying disease state that affects the need for that nutrient?

When clinical studies are designed without taking this paradigm into account, they are doomed to fail. Let me give you some specific examples.

  • The Heart Outcomes Prevention Evaluation study concluded supplementation with folate and other B vitamins did not reduce heart disease risk. The problem was that 70% of the people in the study were getting adequate amounts of folate from their diet at the beginning of the study. For those individuals not getting enough folate in their diet, B vitamin supplementation decreased their risk of heart disease by 15%. This is an example of poor diet influencing the need for supplementation.

The other three examples come from studies on the effect of vitamin E supplementation on heart disease that I summarized in an article in “Health Tips From The Professor” a few years ago. Here is a brief synopsis.

  • The Women’s Health Study concluded that vitamin E did not decrease heart disease risk in the general population. However, the study also found that in women over 65 (who are at high risk of heart disease), vitamin E supplementation decreased major cardiovascular events and cardiovascular deaths by 25%. This is an example of increased need because of age and gender influencing the need for supplementation.
  • The Women’s Antioxidant Cardiovascular Study” concluded that vitamin E did not decrease heart disease risk in the general population. However, when they looked at women who already had cardiovascular disease at the beginning of the study, vitamin E supplementation decreased risk of heart attack, stroke, and cardiovascular death by 23%. This is an example of an underlying disease affecting the need for supplementation.
  • The HOPE study concluded that vitamin E did not decrease heart disease risk in the general population. However, when they looked at individuals with a mutation that increases the risk of heart disease, vitamin E supplementation significantly decreased their risk of developing heart disease. This is an example of genetics affecting the need for supplementation.

These are just a few of many examples. When you ask whether supplementation benefits everyone, the answer is often no. However, when you look at people with inadequate diet, increased need, underlying disease, and/or genetic predisposition, the answer is often yes.

This background sets the stage for the current study. Of course, to understand the author’s hypothesis that mutations in genes involved in vitamin D metabolism might influence the effect of vitamin D on the risk of developing type 1 diabetes, you need to know a little about vitamin D metabolism.

Biochemistry 101: Vitamin D Metabolism

Vitamin D MetabolismWhen sunlight strikes a metabolite of cholesterol in our skin, it is converted to a precursor that spontaneously isomerizes to form vitamin D3. Because this series of reactions is usually not sufficient to provide all the vitamin D3 our bodies require, we also need to get vitamin D3 from diet and supplementation.

However, vitamin D3 is not active by itself. It first needs to be converted to 25-hydroxyvitamin D by our liver and then to the active 1,25-dihydroxyvitamin D. 1,25-dihydroxyvitamin D is an important hormone that regulates many cells in our body.

Some of the 1,25-dihydroxyvitamin D is synthesized by our kidneys and released into the bloodstream. This 1,25-dihyroxyvitamin D binds to vitamin D receptors on the surface of many cells and initiates regulatory pathways that affect metabolism inside the cell.

Other cells take up 25-hydroxyvitamin D and convert it to 1,25-dihydroxyvitamin D themselves. In these cells both the synthesis and regulatory effects of 1,25-dihydroxyvitamin D occur entirely inside the cell.

In both cases, it is 1,25-dihydroxyvitamin D that regulates cellular metabolism. The only difference is the way this regulation is accomplished.

There are two additional points that are relevant to this study.

  • The efficiency of conversion of vitamin D to 25-hydroxyvitamin D varies from person to person.
    • Thus, blood levels of 25-hydroxyvitamin D are considered a more reliable measure of vitamin D status than dietary intake of vitamin D or sun exposure.
    • Blood levels of 25-hydroxyvitamin D levels ≥50 nmol/L are considered optimal, while levels of 30 to <50 nmol/L are considered suboptimal, and levels <30 nmol/L are considered deficient.
  • 1,25-dihydroxyvitamin D binds to the vitamin D receptor on immune cells. This initiates a series of reactions that decrease the risk of autoimmune responses by our immune system.

How Was This Study Done?

Clinical StudyThis study was called TEDDY (The Environmental Determinants Of Type 1 Diabetes in the Young). Between September 2004 and February 2010, 424,788 newborn infants from 6 medical centers in Colorado, Georgia, Washington, Finland, Germany, and Sweden were screened for genes that predispose to type 1 diabetes.

The investigators identified 21,589 high-risk infants, and 8,676 of them were enrolled in this study before age 4 months. Clinic visits for the children occurred every 3 months between 3 and 48 months of age and every 6 months thereafter.

  • A DNA sample was taken at the time they entered the study and analyzed for mutations in genes involved in vitamin D metabolism.
  • 25-hydroxy vitamin D levels were obtained at each office visit. Because some studies have suggested the vitamin D status during the first year of life is important, the data were analyzed in two ways.
    1. An average of all 25-hydroxyvitamin D levels (referred to as “childhood 25-hydroxyvitamin D levels”).
    1. An average of 25-hydroxyvitamin D levels during the first 12 months (referred to as “early infancy 25-hydroxyvitamin D levels”).
  • Serum autoantibodies to pancreatic islet cells were measured at each office visit as a measure of an autoimmune attack on those cells. Persistent autoimmune response was defined as positive autoantibodies on two consecutive office visits.

While this study did not directly measure type 1 diabetes, children with an autoimmune response to their pancreatic islet cells are highly likely to develop type 1 diabetes. Thus, for purposes of simplicity I will refer to “risk of developing type 1 diabetes” rather than “persistent autoimmune response” in describing these results.

    1. 418 children developed persistent autoantibodies to their pancreatic islet cells during the study. The onset of this autoimmune response ranged from 2 months to 72 months with an average of 21 months.
    1. These children were compared to 3 matched controls from their medical center who did not develop an autoimmune response.

This study was remarkable for two reasons:

1) It was much larger than previous studies. This gave it greater power to detect an effect of vitamin D status on the risk of developing type 1 diabetes.

2) This was the first study to ask whether mutations in genes controlling the metabolism of vitamin D influenced the effect of vitamin D on the risk of developing type 1 diabetes.

Does Vitamin D Prevent Type 1 Diabetes?

Vitamin DThe study compared the risk of developing type 1 diabetes in children whose 25-hydroxyvitamin D levels were optimal (≥50 nmol/L) to children whose 25-hydroxyvitamin D levels were suboptimal (30 to <50 nmol/L). The results were:

  • Optimal vitamin D status during childhood was associated with a 31% decrease in the risk of developing type 1 diabetes.
  • Optimal vitamin D status during early infancy (first 12 months) was associated with a 40% decrease in the risk of developing type 1 diabetes.

In other words, having optimal vitamin D status significantly reduces the likelihood of developing of type 1 diabetes in childhood.

  • 25-hydroxyvitamin D levels >75 nmol/L provided no additional benefit.

In other words, you need sufficient vitamin D, but higher levels provide no additional benefit.

  • They tested 5 genes involved in vitamin D metabolism to see if they influenced the effect of vitamin D on the risk of developing type 1 diabetes. Only the VDR (vitamin D receptor) gene had any influence.
    • When the VDR gene was fully functional, optimal vitamin D status had no effect on the risk of developing type 1 diabetes. This means that even suboptimal (30 to <50 nmol/L) levels of 25-hydroxyvitamin D were sufficient to prevent type 1 diabetes when the vitamin D receptor was fully functional.
    • Only 9% of the children in this study were vitamin D deficient (<30 nmol/L 25-hydroxyvitamin D). Presumably, these children would be at high risk of developing type 1 diabetes even with a fully functional VDR gene. However, there were not enough children in that category to test this hypothesis.
  • When they looked at children with mutations in the VDR gene:
    • Optimal vitamin D status during childhood was associated with a 59% decrease in the risk of developing type 1 diabetes.
    • Optimal vitamin D status during early infancy (first 12 months) was associated with a 67% decrease in the risk of developing type 1 diabetes.

In short, the need for optimal vitamin D levels to reduce the risk of developing type 1 diabetes is only seen in children with a mutation in the VDR (vitamin D receptor) gene.

  • This is a clear example of genetics affecting the need for a nutrient.
    • For children with a fully functional VDR gene, even 30-50 nmol/L 25-hydroxyvitamin D was sufficient to reduce the risk of developing type 1 diabetes.
    • However, children with mutations in the VDR gene required ≥50 nmol/L 25-hydroxyvitamin D to reduce their risk of developing type 1 diabetes.
  • This is also an example of genetics affecting the need for supplementation with vitamin D.
    • 42% of the children in this study had suboptimal levels of 25-hydroxyvitamin D. Those who also have a mutation in the VDR gene would require supplementation to bring their 25-hydroxyvitamin D up to the optimal level to reduce their risk of developing type 1 diabetes.
    • Other studies have estimated that up to 61% of children in the US may have suboptimal 25-hydroxyvitamin D levels.

What Does This Study Mean For You?

Questioning WomanLet’s start with the three questions I proposed at the beginning of this article.

1) Does vitamin D prevent type 1 diabetes? Based on this study, the answer appears to be a clear yes. However, this is the first study of this kind. We need more studies that into account the effect of mutations in the VDR gene.

2) If so, is supplementation with vitamin D important? If we think in terms of supplementation with RDA levels of vitamin D or sufficient vitamin D to bring 25-hydroxyvitamin D into the optimal range, the answer is also a clear yes. However, there is no evidence from this study that higher doses of vitamin D provide additional benefits.

3) Who will benefit most from vitamin D supplementation? Based on this study, the children who will benefit the most from vitamin D supplementation are those who have a suboptimal vitamin D status and have a mutation in the VDR (vitamin D receptor) gene. To put this into perspective:

    • Up to 60% of children and adults in this country have suboptimal vitamin D levels.
    • The percentage of suboptimal vitamin D levels is highest for people who are obese, have pigmented skin, are institutionalized (eg, elderly in nursing homes), and/or live far from the equator.
    • Supplementation with a multivitamin containing the RDA for vitamin D reduces the risk of having suboptimal vitamin D status by 2.5 to 5-fold depending on the person’s ethnicity.
    • This study may be just the tip of the iceberg. The vitamin D receptor is also found on many other cells that control important biological functions.

Finally, if you are a parent or parent-to-be, you probably have several questions. Here are the ones I have New Parentsanticipated:

#1: Is my child at risk for developing type 1 diabetes? If you or a close family member has type 1 diabetes, you can assume your child is genetically predisposed to developing type 1 diabetes. Other factors that increase your child’s risk of developing type 1 diabetes are obesity, non-White ethnicity, and geographical location far from the equator.

#2: Should I have my baby tested for genetic predisposition to type 1 diabetes? That is not currently recommended. Just be aware of the risk factors listed above.

#3: Should I have my baby tested for VDR mutations? That is unnecessary. If your child has a VDR mutation, they just need sufficient vitamin D, not mega doses of vitamin D. And there are lots of other reasons for making sure your child gets sufficient vitamin D.

#4: How much vitamin D should my child be getting? The recommendation is 400 IU up to age 1 and 600 IU over age 1.

#5: Should I give my child vitamin D supplements? It is a good idea. For children over age 1, I recommend a multivitamin supplying 600 IU of vitamin D.

For infants, the American Association of Pediatrics recommends 400 IU vitamin D drops, regardless of whether the infants are breast or formula fed. That is because studies during the first year of life show that less than one-fifth of all infants get the recommended 400 IU/d from any source, and fewer than one out of 10 breast-fed infants meet the requirement – even if the mother is getting adequate vitamin D in their diet.

One Caution: I do not recommend exceeding 400 IU for infants or 600 IU for children unless directed by your health care provider. In terms of the risk of developing type 1 diabetes, your child needs sufficient vitamin D, and more is not better.

#6: Should I have my child tested for 25-hydroxyvitamin D levels? That is not done routinely at the present time. However, if your child has one or more of the risk factors listed above, it is a conversation you should have with your health care provider.

The Bottom Line

While it is widely accepted that vitamin D helps reduce the risk of developing type 1 diabetes in childhood, that has been difficult to prove. Clinical studies have provided conflicting results. The authors of a recent study postulated that the discrepancies between studies may have arisen because the studies neglected the effect of mutations in genes controlling vitamin D metabolism which may affect the ability of vitamin D to reduce the risk of developing type 1 diabetes.

This study found that:

1) Infants and children with optimal vitamin D status (25-hydroxyvitamin D levels ≥50 nmol/L) were 31-40% less likely to develop type 1 diabetes than children with suboptimal vitamin D status (25-hydroxyvitamin D = 30 to <50 nmol/L).

2) However, the effect of vitamin D on the risk of developing type 1 diabetes was only seen in children with one or more mutations in the VDR (vitamin D receptor) gene. To interpret this observation, you need to know that:

    • Type 1 diabetes is caused by an autoimmune attack on the pancreatic islet cells that release insulin.
    • 1,25-dihydroxyvitamin D promotes immune tolerance and decreases the risk of autoimmune responses.
    • 1,25-dihydroxyvitamin D exerts this effect by binding to the vitamin D receptor on the surface of immune cells.

3) Thus, mutations in the VDR gene modify the effect of vitamin D on the risk of developing type 1 diabetes. Specifically:

    • When the VDR gene is fully active, even suboptimal levels of vitamin D appear to be sufficient to prevent the development of type 1 diabetes in childhood.
    • However, when the VDR gene has mutations that reduce its activity, suboptimal levels of vitamin D no longer prevent type 1 diabetes. Optimal levels of vitamin D are required to reduce the risk of developing type 1 diabetes.

This is an example of genetics increasing the need for a nutrient (vitamin D) and increasing the need for supplementation to make sure that optimal levels of that nutrient are achieved.

While this study focused on the effect of vitamin D on the development of type 1 diabetes, this may just be the tip of the iceberg. The vitamin D receptor is also found on many other cells that control important biological functions.

For more details, read the article above. You will probably want to read the section “What Does This Mean For You?”, including my recommendations for parents of young children

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease.

Preparing For The New Normal

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Can Supplements Strengthen My Immune System?

COVID-19The United States and the rest of the world are facing the biggest challenge of our lifetimes. COVID-19 has killed hundreds of thousands of people and decimated economies around the world.

As of the publication date of this article we have no vaccine and only one treatment option that appears to be about 30% effective in a preliminary clinical trial. People are scared.

The question I get asked most often is: “Can supplements protect me from COVID-19”. That’s not a question I can answer with confidence. The few studies we have are small and preliminary. Plus, there is too much we still do not know about COVID-19.

However, there are studies about how diet and supplements affect the immune system. I can answer the question, “Can Supplements Strengthen My Immune System”, with confidence. That will be the focus of this article.

However, before covering that, let me take an objective look at what our “New Normal” will be like and how we can prepare for it.

Preparing For The New Normal

ProfessorAs a scientist I am appalled by the divisive and hyper-partisan arguments about how we should be handling the COVID-19 pandemic. This is a time when our country should be united against a common enemy. Instead I see myths and lies propagated on both sides of this important issue.

The press only magnifies the problem by repeating the myths without fact checking. Whether they are on the left or the right, the media only repeats myths that fit their narrative. As a result, people like you are confused and scared.

Let me try to give you a more objective and scientific view of what the “New Normal” will look like, and how we can prepare for it.

Let’s start with one of the biggest arguments over the past few weeks – when should we reopen our country. This argument is based on the myth that if we wait long enough, the virus will be gone, and life can return to normal.

Nothing could be further from the truth. In reality viruses don’t work that way. They continue to circulate through the population at low levels. Whenever we emerge from our homes and resume our daily lives, the virus will be lurking. There will be flare-ups. There will be hot spots. There will be deaths. And the press will report every one.

So, the question should not be when we emerge. It should be how we emerge. We should emerge cautiously. We should continue to take appropriate precautions. These precautions will become our “New Normal” until we have an effective vaccine. By now, you probably have the CDC precautions memorized, but let me repeat them here:

  • If you are sick, stay home until you recover. If your symptoms worsen, contact your doctor right away.
  • If you are exposed, get tested right away and self-quarantine for 14 days if you test positive.
  • When you go out, wear a face mask and practice social distancing. When you get home, wash your hands in soap and water for 20”.
  • For now, we will need to avoid the customary handshake (and if you are from the South like me, the customary hug).
  • If you are very old or very sick, you should stay home as much as possible. If you have a loved one in this category, you should do everything in your power to protect them from exposure.
  • The guideline that is hardest to project into the future is the one on crowd size. It is hard to predict what the CDC will recommend about crowd size as part of our “New Normal” a few months from now. However, because this virus is extremely contagious, it may be risky to attend any gatherings where there are large, tightly packed crowds for the foreseeable future. This could include some of our favorite things – like movies, live theater, night clubs, and sporting events.Myth Versus Facts

Finally, there is another big myth, namely that the virus will simply disappear once we have a vaccine. Vaccines reduce your risk of exposure because fewer people are carriers of the virus. However, coronaviruses never disappear. They continue to circulate in the population for decades.

Even after we have a vaccine, people will still get sick from COVID-19. People will still die from COVID-19. The difference is that we will no longer hear about COVID-19 cases and deaths on the nightly news. Those cases and deaths will just become part of the statistics that the CDC collects on flu-like illnesses each year – and everyone ignores.

Now that I have discussed what the “New Normal” will look like and summarized the CDC guidelines for reducing your exposure to COVID-19 as the lockdown eases, let me add another guideline of my own:

  • Keep your immune system as strong as possible.

Why Is Keeping Your Immune System Strong Important?

strong immune systemIt is no secret that the media likes to focus on bad news. It is the bad news that draws people in and keeps them coming back for more.

Pandemics are no different. It doesn’t matter whether we are talking about the Spanish flu, SARS, MERS, or COVID-19. We focus on cases and deaths – the bad news. We ignore the good news – there are millions of people who were infected and had no symptoms.

However, if you have been listening closely to what the experts have been saying rather than relying on the media for your information, the good news is obvious.

  • 80-85% of people who have tested positive for COVID-19 have mild or moderate symptoms. Their symptoms are no worse than they experience with the seasonal flu.
  • Preliminary antibody tests suggest that the number of people infected with COVID-19 who experience no symptoms may be 10 to 40 times higher than reported cases.
  • The experts say that the difference is a strong immune system. They tell us that it is people with weakened immune systems that suffer and die from COVID-19.

So, how do you keep your immune system strong? Let’s start by looking at the role of supplementation.

Can Supplements Strengthen My Immune System?

MultivitaminsThose of you who follow me know that I consider supplementation as just one aspect of a holistic approach to health. However, I am starting with supplements because the question I am often asked these days is: “Can supplements protect me from COVID-19”.

As I said at the beginning of this article, that is not a question I can answer with confidence. Instead, the question you should be asking is, “Can Supplements Strengthen My Immune System?”

As I mentioned above, the experts are telling us that it is people with weakened immune systems who suffer and die from COVID-19. That means it is important to keep our immune system as strong as possible.

How do we do that? Here is what an international group of experts said in a recent review (PC Calder et al, Nutrients, 12, 1181-1200, 2020).

1) “A wealth of mechanistic and clinical data show that vitamins A, B6, B12, C, D, E, and folate; trace elements zinc, iron, selenium, magnesium, and copper; and omega-3 fatty acids EPA and DHA play important and complementary roles in supporting the immune system.”

2) “Inadequate intake and status of these nutrients are widespread, leading to a decrease in resistance to infections, and an increase in disease burden.”

They then made the following recommendations:

1) Supplementation with the above micronutrients and omega-3 fatty acids is a safe, effective, and low-cost strategy to help support optimal immune function.

    • They recommended 100% of the RDA for vitamins A, B6, B12, C, D, E, and folate and minerals zinc, iron, selenium, magnesium, and copper in addition to the consumption of a well-balanced diet.
    • They recommended 250 mg/day of EPA + DHA.

2) Supplementation above the RDA for vitamins C and D is warranted.

    • They recommend 200 mg/day of vitamin C for healthy individuals and 1-2 g/day for individuals who are sick.
    • They recommend 2000 IU/day (50 ug/day) for vitamin D.

3) Public health officials are encouraged to include nutritional strategies in their recommendations to improve public health.

Their recommendations could be met by a multivitamin that provides all the micronutrients they recommend, an omega-3 supplement, and extra vitamins C and D.

What Else Should I Do To Strengthen My Immune System?

healthy foodsAs I said above, supplementation is only one part of a holistic approach to a strong immune system. Here are the other components of a holistic approach:

1) It starts with a healthy diet.

    • Eat foods from all 5 food groups.
    • Eat plenty of fruits and vegetables. They provide antioxidants and phytonutrients that are important for our immune system.
    • Eat plenty of high fiber foods. Include whole grains and beans in addition to fruits and vegetables. That’s because the friendly gut bacteria that strengthen our immune system need a variety of fibers from different food sources to feed on.
    • Eat oily fish on a regular basis.
    • Avoid sodas, sugary foods, and highly processed foods.
    • Avoid high fat diets

2) Get adequate sleep. For most of us, that means 7-8 hours of sleep a night.

3) Maintain a healthy weight.

4) Get adequate exercise. Aim for a minimum of 150 minutes of moderate intensity exercise each week.

5) Manage stress and anxiety in healthy ways. Yes, that means if you let the news about COVID-19 cause anxiety, you are weakening your immune system. You may want to turn off the news and try prayer, meditation, yoga, or whatever relieves stress for you.

The Bottom Line

In this article, I summarized the “New Normal” we face as we emerge from lockdown and how to navigate the new normal as safely as possible. If I were to summarize this article in a few short sentences, this is what I would say:

Until we have an effective vaccine the “New Normal” is a world in which a dangerous virus is lurking in the community, waiting to strike the unprepared.

Forget all the angry rhetoric about when we should emerge from lockdown. The important question is not when we emerge. It is how we emerge.

We don’t need to stay huddled in our homes, fearful to leave, unless we are very old or very sick.

We do need to take appropriate precautions when we leave home based on the recommendations of the CDC. None of us are invincible as far as this virus is concerned. More importantly, if we bring the virus home, we may kill the very people we love the most. We need to follow the guidelines.

We should also make sure that our immune system is as strong as possible through a holistic combination of diet, supplementation, adequate sleep, exercise, weight management, and stress reduction.

For more information on CDC COVID-19 Guidelines, click here.

For more details about preparing for the new normal and diet & supplementation recommendations, read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease.

Does Vitamin D Affect Muscle Strength?

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Why Is Vitamin D Research So Controversial?

vitamin dMost people lose muscle strength as they age, something called sarcopenia. This is not a trivial matter. Loss of muscle mass:

  • Leads to loss of mobility. It can also make it difficult to do simple things like lifting your grandchild or carrying a bag of groceries.
  • Increases your risk of falling. This often leads to serious fracture which increases your of dying prematurely. In fact, bone fractures increase your risk of dying by 3-fold or more. Even in those who recover their mobility and quality of life may never be the same.
  • Lowers your metabolic rate. This increases your risk of obesity and all the diseases that are associated with obesity.

Loss of muscle strength as we age is preventable. There are several things we can do to preserve muscle strength as we age, but in today’s article I will focus on the effect of vitamin D on muscle strength.

What if something as simple as preventing vitamin D deficiency could improve muscle strength as we age? That idea has been around for a decade or more. But, for reasons I will detail below, it has proven controversial. Let me start by sharing the latest study on vitamin D and muscle strength (N Aspell et al, Clinical Investigations in Ageing, volume 2019:14, pages 1751-1761).

How Was The Study Done?

Clinical StudyThe data for this study came from 4157 adults who were enrolled in the English Longitudinal Study On Aging. Participants in this study were all over the age of 60 and were still living in their own homes. The general characteristics of the study population were:

  • Their average age was 69.8 with 45% male and 55% female.
  • While 76% of the participants rated their health as “good” or above
    • 73% were overweight or obese.
    • 54% had a longstanding disease that limited mobility.
    • 29% were taking multiple medications.

Serum 25-hydroxy vitamin D levels were determined as a measure of vitamin D status.

  • 22% of the participants were vitamin D deficient (<30 nmol/L 25-hydroxy vitamin D).
  • 34% of the participants were vitamin D insufficient (between 30 and 50 nmol/L 25-hydroxy vitamin D).
  • 46% of the participants had adequate vitamin D status (>50 nmol/L 25-hydroxy vitamin D).

Muscle strength was assessed by a handgrip strength test with the dominant hand. Muscle performance was assessed with something called the short physical performance battery (SPPB), consisting of a walking speed test, a repeated chair raise test, and a balance test.

Does Vitamin D Affect Muscle Strength?

When the data on handgrip strength were analyzed:

  • Only 22% of the participants who had adequate vitamin D status had low handgrip strength.
  • 40% of participants who were vitamin D deficient had low handgrip strength. That’s almost a 2-fold difference.
  • Handgrip strength increased linearly with vitamin D status.
    • The relationship between vitamin D status and handgrip strength was highly significant (p<001).
    • The beneficial effect of vitamin D status on handgrip strength plateaued at around 55-69 nmol/L 25-hydroxy vitamin D. In other words, you need adequate vitamin D status to support muscle strength, but higher levels provide no additional benefit.

When the data on muscle performance (the SPPB test) were analyzed:

  • Only 8% of the participants who had adequate vitamin D status scored low on this test.
  • 25% of participants who were vitamin D deficient scored low on this test. That’s a 3-fold difference.
  • Muscle performance also increased linearly with vitamin D status.
    • The relationship between vitamin D status and muscle performance was also highly significant (p<001).
    • The beneficial effect of vitamin D status on muscle performance also plateaued at around 55-69 nmol/L 25-hydroxy vitamin D.

The authors concluded: “Vitamin D deficiency was associated with impaired muscle strength and performance in a large study of community-dwelling older people. It is generally accepted that vitamin D deficiency should be reversed to prevent bone disease. This strategy may also protect skeletal muscle function in aging.”

Why Is Vitamin D Research So Controversial?

ArgumentYou can be forgiven if you are saying to yourself: “I’ve heard this sort of thing before. I see a blog or headline claiming that vitamin D has a certain benefit, but it’s usually followed by later headlines saying those claims are false. Why can’t the experts agree? Is all vitamin D research bogus?”

The relationship between vitamin D status and muscle strength is no different.

  • Most, but not all, studies looking at the association between vitamin D status and muscle strength find that vitamin D status affects muscle strength.
  • However, many randomized, placebo-controlled clinical trials looking at the effect of vitamin D supplementation on muscle strength have come up empty.

A meta-analysis (L Rejnmark, Therapeutic Advances in Chronic Disease, 2: 25-37, 2011) of randomized, placebo-controlled clinical trials of vitamin D supplementation and muscle strength provides insight as to why so many of them come up empty.

The meta-analysis combined data from 16 clinical trials. The conclusions were similar to what other meta-analyses have found:

  • Seven of the studies showed a benefit of vitamin D supplementation on muscle strength. Nine did not.
  • When the data from all 16 studies were combined, there was only a slight beneficial effect of vitamin D supplementation on muscle strength.

However, it was in the discussion that the reason for these discrepancies became apparent. There were three major deficiencies in study design that were responsible for the discrepancies.

1) There was a huge difference in study design.

    • The subjects were of different ages, genders, and ethnicities.
    • The dose of vitamin D supplementation varied.
    • Different measures of muscle strength and performance were used.

Until the scientific and medical community agree on a standardized study design it will be difficult to obtain consistent results.

While this deficiency explains the variation in outcomes from study to study, there are two other deficiencies in Garbage In Garbage Outstudy design that explain why many of the studies failed to find an effect of vitamin D on muscle strength. I call this “Garbage In, Garbage Out”. Simply put, if the study has design flaws, it may be incapable of detecting a positive effect of vitamin D on muscle strength.

2) Many of the studies did not measure vitamin D status of the participants at the beginning of the study.

    • The results of the study described above show that additional vitamin D will be of little benefit for anyone who starts the study with an adequate vitamin D status.
    • In the study above 46% of the participants had adequate vitamin D status. This is typical for the elderly community. When almost 50% of the participants in a study have adequate vitamin D status at the beginning of a study it becomes almost impossible to demonstrate a beneficial effect of vitamin D supplementation on any outcome.

It is essential that future studies of vitamin D supplementation start with participants who have low vitamin D status. Otherwise, you are almost guaranteeing a negative outcome.

3) Most of the studies ignored the fact that vitamin D status is only one of three factors that are essential for muscle strength.

    • In the case of muscle strength, especially in the elderly, the three essentials are vitamin D, protein, and exercise. All three are needed to maintain or increase muscle strength. Simply put, if one is missing, the other two will have little or no effect on muscle strength. Unfortunately, you cannot assume that exercise and protein intake are adequate in older Americans:
      • Many older adults don’t get enough exercise because of physical limitations.

Unfortunately, many clinical studies on the effect of vitamin D supplementation and muscle strength fail to include exercise and adequate protein intake in the study. Such clinical trials are doomed to failure.

Now you know why vitamin D research is so controversial. Until the scientific and medical community get their act together and perform better designed experiments, vitamin D research will continue to be controversial and confusing.

What Does This Mean For You?

Old Man Lifting WeightsLoss of muscle mass as we age is not a trivial matter. As described above, it:

  • Leads to loss of mobility.
  • Increases your risk of falling. This often leads to serious fracture which increase your risk of disability and death.
  • Lowers your metabolic rate, which increases your risk of obesity and obesity-related diseases.

So, what can you do prevent loss of muscle mass as you age? The answer is simple:

1) Aim for 25-30 grams of high-quality protein in each meal.

    • That protein can come from meat, fish, eggs, or legumes.
    • That doesn’t mean you need to consume an 8-ounce steak or a half chicken. 3-4 ounces is plenty.
    • However, it does mean you can’t subsist on green salads and leafy greens alone. They are healthy, but you need to include a good protein source if you are going to meet your protein needs.

2) Aim for 150 minutes of moderate intensity exercise per week.

    • At least half of that exercise should be resistance exercise (lifting weights, for example).
    • If you have physical limitations, consult your doctor and a physical therapist or personal trainer to design resistance exercises you can do.
    • Aim for a variety of resistance exercises. You will only strengthen the muscles you exercise.

3) Aim for an adequate vitamin D status.

    • Start with a multivitamin containing at least 800 IU of vitamin D3.
    • Because there is large variation in the efficiency with which we convert vitamin D to 25-hydroxy vitamin D, you should get your serum 25-hydroxyvitamin D tested on a yearly basis. Your health professional can tell you if you need to take larger amounts of vitamin D3.
    • This study suggests that a serum 25-hydroxy vitamin D level of 55-69 nmol/L is optimal, and higher levels provide no additional benefit. That means there is no need to take mega-doses of vitamin D3 unless directed by your health professional.

The Bottom Line

A recent study looked at the effect of vitamin D status on muscle strength and performance in a healthy population with an average age of 69.

When they looked at handgrip strength:

  • Only 22% of the participants with an adequate vitamin D status had low handgrip strength.
  • 40% of participants who were vitamin D deficient had low handgrip strength. That’s almost a 2-fold difference.
  • Handgrip strength increased linearly with vitamin D status.

When they looked at muscle performance:

  • Only 8% of the participants with an adequate vitamin D status scored low on this test.
  • 25% of participants who were vitamin D deficient scored low on this test. That’s a 3-fold difference.
  • Muscle performance also increased linearly with vitamin D status.

The authors concluded: “Vitamin D deficiency was associated with impaired muscle strength and performance in a large study of community-dwelling older people. It is generally accepted that vitamin D deficiency should be reversed to prevent bone disease. This strategy may also protect skeletal muscle function in aging.”

If we look at the research more broadly, there are three factors that are essential for maintaining muscle mass as we age: exercise, protein, and vitamin D. Therefore, my recommendations are to:

1)  Aim for 25-30 grams of high-quality protein in each meal.

2) Aim for 150 minutes of moderate intensity exercise per week. At least half of that exercise should be resistance exercise.

3) Aim for an adequate vitamin D status (>50 nmol/L of serum 25-hydroxy vitamin D). A good place to start is with a multivitamin providing at least 800 IU of vitamin D3.

For more details on my recommendations and a discussion of why studies on vitamin D supplementation are often confusing, read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

 

Health Tips From The Professor