Vitamin D Supplements Archives - Health Tips From The Professor

Can You Slow The Aging Process?

July 11, 2023 by Dr. Steve Chaney

A Holistic Approach To Living Healthy Longer

Author: Dr. Stephen Chaney

Ever since Ponce de Leon’s famed 1513 expedition, people have been searching for the proverbial “Fountain of Youth”.

There have been hucksters selling pills and potions to reverse the aging process. Most of them didn’t work. They were no better than snake oil.

There have been legitimate scientists investigating the effect of supplements, diets, and lifestyle on the aging process. Most of these studies have come up empty.

In this study (M Gagesch et al, Journal of Frailty And Aging, 12: 71-77, 2023) the authors hypothesized that a holistic approach might be better than individual interventions. They asked whether a combination of vitamin D3 supplementation, omega-3 supplementation, and exercise might be more effective at slowing the aging process than any one of them alone.

There was good reason for choosing each of these interventions:

Low 25-hydroxyvitamin D levels have been associated with frailty in several studies. But association studies do not prove cause and effect, and no randomized, placebo control studies have measured the effect of vitamin D supplementation on frailty.

Omega-3 fatty acids have been linked to skeletal muscle health, and some studies have suggested omega-3 supplementation may improve muscle function in older adults.

A recent study has reported that a supervised exercise program reduced frailty in older adults. The authors wanted to see if the same was true for unsupervised, at-home exercise program.

How Was This Study Done?

The data from this study were collected as part of the DO-HEALTH study, a 3-year, double-blind, randomized, placebo-controlled clinical trial designed to identify interventions that support healthy aging in European adults aged 70 and older.

Initially, 2,157 healthy, community-dwelling adults were enrolled from five countries (Switzerland, Germany, Austria, France, and Portugal). They were examined in clinical centers at the beginning of the study and years 1, 2, and 3, with phone follow-up at 3-month intervals.

Aging was measured by something called the frailty index. At each clinic visit the participants were evaluated in five areas:

Weakness was measured as grip strength. Weakness was defined as being in the lowest quintile of grip strength for someone their age and gender.

2) Fatigue was defined as a positive answer to the question, “In the last month have you had too little energy to do the things you wanted to do?”

3) Involuntary weight loss was defined as >5% weight loss within a year.

4) Low gait speed was defined as <2 ft/sec walking speed.

5) Low activity level was defined as a response of, “Less than once a week” to the question, “How often do you engage in activities that require a low or moderate level of energy such as gardening, cleaning the car, or going on a walk?”

- Participants with 0 positive items were classified as robust.
- Those with 1 or 2 positive items were classified as pre-frail.
- Those with 3 or more positive items were classified as frail.

Only those participants from the DO-HEALTH study classified as robust at the first clinical visit (1,137 participants) were included in this study. The study measured how many of them became pre-frail or frail during the average follow-up of 2.9 years.

The interventions were:

Capsules containing a total of 2,000 IU/day of vitamin D3 with sunflower oil capsules as a placebo.

Capsules containing a total of 1,000 mg of EPA and DHA in a 1:2 ratio with a sunflower oil capsule as a placebo.

Exercise consisting of an unsupervised strength-training routine for 30 minutes, 3 times per week.

In this case the control was an unsupervised joint-flexibility routine for 30 minutes, 3 times per week.

The interventions were done individually, two together (vitamin D + omega-3, vitamin D + exercise, omega-3 + exercise), and all three together (vitamin D + omega-3 + exercise).

The results were corrected for age, sex, and low-trauma falls in the preceding 12 months.

Finally, the study measured blood 25-hydroxyvitamin D levels and omega-3 levels at each office visit. They found:

28% of the participants were deficient in vitamin D at the beginning of the study.
The interventions gave the expected increase in vitamin D and omega-3 status.

Can You Slow The Aging Process?

At the end of 3 years:

61.2% of the participants had declined from robust health to the pre-frail category.

2.6% of the participants had declined from robust health to the frail category.

[Note: The terms “pre-frail” and “frail” are measures of aging which I have described above.]

The number of participants in the frail category were too small to obtain a statistically significant measure of the effects of vitamin D, omega-3s, and exercise on frailty, so I will only discuss the results measuring their effect on pre-frailty in this review. These results are:

None of these interventions had a statistically significant effect on aging by themselves, as measured by the transition from robust health to pre-frailty.

None of these interventions had a statistically significant effect on aging when combined in pairs, although the vitamin D3-omega-3 pair came close to significance (31% reduction in pre-frailty with a probability of 94% (probabilities of 95% and above are considered significant.))

However, the combination of vitamin D3, omega-3s, and exercise reduced the risk of aging by 39%, which was statistically significant (96% probability).

The authors concluded, “Robust, generally healthy and active older adults without major comorbidities [diseases], may benefit from a combination of high-dose, supplemental vitamin D3, marine omega-3s, and SHEP [unsupervised strength training] with regard to the risk of becoming pre-frail over 3 years.”

A Holistic Approach To Living Healthy Longer

This study was a double-blind, placebo-controlled study, which is the gold standard for clinical studies. It was also unusually large (1,137 participants) and long (3 years) for this kind of study.

It was also much better than most double-blind, placebo-controlled studies in that it included three interventions (vitamin D3 supplementation, omega-3 supplementation, and exercise) and looked at their effect on aging individually, in pairs, and all three together.

One take-home lesson from this study was that a holistic approach that included all 3 interventions was superior to any one of these interventions alone or in pairs.

But the most important take-home lesson is this:

If you asked your doctor what you should do to slow the aging process, he or she would probably tell you, “Exercise may help, but forget supplementing with extra vitamin D or omega-3s. They have no proven benefits.”

They would be correct based on studies of each of these interventions individually. And the studies they might quote would be double-blind, placebo-controlled studies, the gold standard of clinical studies.

But would that be the best advice. Clearly not. The best advice would be to follow a holistic approach and use all 3 interventions together.

Unfortunately, this is true for most studies of supplementation. Supplements are tested individually, as if they were “magic bullets”. And most of these studies come up short. They fail to find a significant benefit of supplementation.

Supplements are almost never tested holistically in combination with each other and other interventions, but that’s where the “magic” really happens.

If you are a regular reader of “Health Tips From The Professor”, this should come as no surprise to you. I have often shared the Venn diagram on the upper left and said that the sweet spot is when two or more of these interventions overlap.

Of course, this is the first study of its kind. More studies are needed. More importantly, we need studies to fill in the other parts of the Venn diagram. We need to ask about the effect of diet and obesity on aging. For example:

If we add a healthy diet to vitamin D, omega-3s, and exercise, can we reduce aging even more dramatically?

Is the effort it takes to lose excess weight worth it? Does adding it to diet, supplementation, and exercise reduce the aging process even more?

Of course, I think the answer to those questions is an unequivocal, “Yes”. Multiple studies have shown that both a healthy weight and a healthy diet help you live healthier longer.

But I am a scientist. Neither diet nor weight loss have been tested in combination with supplementation and exercise. I would like to see studies combining all these modalities in a single double-blind, placebo-controlled experiment.

So, what does this mean for you? If you want to slow the aging process, if you are in search of your personal “Fountain of Youth…

This study suggests that vitamin D3 supplementation (2,000 IU/day), omega-3 supplementation (1,000 mg of EPA + DHA), and an exercise program that emphasizes strength training can help you slow the aging process.

But that is only the beginning. I also recommend…

Including a healthy diet and a healthy weight in your anti-aging regimen.

Making sure your diet has enough protein and leucine, since older adults need more of both to maximize the benefits of strength training.

Including other supplements as evidence for their benefit in slowing the aging process becomes available.

The Bottom Line

A recent double-blind, placebo-controlled study looked at the effect of vitamin D3 supplementation (2,000 IU/day), omega-3 supplementation (1,000 mg/day EPA + DHA in a 1:2 ratio), and an unsupervised strength training program on the aging process.

It differed from most other double-blind, placebo-controlled studies in that:

It was larger (1,137 participants) and longer (3 years) than most.

More importantly, each intervention was tested individually, in pairs, and all 3 together.

The study found that:

None of these interventions had a statistically significant effect on aging by themselves.

None of these interventions had a statistically significant effect on aging when combined in pairs, although the vitamin D3-omega-3 pair came close to significance.

However, the combination of vitamin D3, omega-3s, and exercise reduced the risk of aging by a statistically significant 39%.

One take-home lesson from this study was that a holistic approach that included all 3 interventions was superior to any one of these interventions alone or in pairs.

But the most important take-home lesson is this:

But would that be the best advice? Clearly not. The best advice would be to follow a holistic approach and use all 3 interventions together.

Supplements are almost never tested holistically in combination with each other and other interventions, but that’s where the “magic” really happens.

For more information on this study and my recommendations on how to slow the aging process 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.

___________________________________________________________________________

My posts and “Health Tips From the Professor” articles carefully avoid claims about any brand of supplement or manufacturer of supplements. However, I am often asked by representatives of supplement companies if they can share them with their customers.

My answer is, “Yes, as long as you share only the article without any additions or alterations. In particular, you should avoid adding any mention of your company or your company’s products. If you were to do that, you could be making what the FTC and FDA consider a “misleading health claim” that could result in legal action against you and the company you represent.

For more detail about FTC regulations for health claims, see this link.

https://www.ftc.gov/business-guidance/resources/health-products-compliance-guidance

Which Diets Are Best In 2021?

March 16, 2021 by Dr. Steve Chaney

Which Diet Should You Choose?

Many 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?

US 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 Diets

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

Best 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 Follow

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?

Let 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?

With 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.

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 Prevent Type 1 Diabetes?

June 2, 2020 by Dr. Steve Chaney

Does Genetics Influence Supplementation Benefits?

The 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?

The 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

When 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?

This 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?

The 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?

Let’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 anticipated:

#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.

Does Vitamin D Supplementation Reduce Cancer Deaths?

October 22, 2019 by Dr. Steve Chaney

Why Are Vitamin D Studies So Confusing?

Author: Dr. Stephen Chaney

Does vitamin D supplementation reduce cancer deaths?

When I was in graduate school (which was just a few decades ago), vitamin D was thought to be important for healthy bones and teeth, and that was about it. Its role in calcium metabolism was well established, but we knew little else about its role(s) in the body. In fact, we were taught we knew all we needed to know about vitamin D.

Shortly after I graduated, it was discovered that almost every cell in our body had vitamin D receptors, and vitamin D research exploded. A few years ago, vitamin D appeared to be almost magic. Studies suggested that it:

Strengthened the immune system.
Prevented autoimmune diseases like type 1 diabetes and multiple sclerosis.
Reduced the risk of cancer and heart disease.
Helped regulate insulin levels and aided in type 2 diabetes management.
Supported the health of our lungs, brain, and nervous system.

Those were the headlines that you saw in the news and still see in Dr. Strangelove’s health blogs.

However, when these early studies were followed by a series of double-blind, placebo controlled clinical trials, the only benefit that was consistently validated was the strengthening of our immune system.

That has led to a series of headlines and posts in medical blogs saying things like: “Vitamin D supplements are worthless” and “You should stop taking your vitamin D supplements.”

“What is a person to believe? Why is it so confusing?”

In this week’s issue of “Health Tips From the Professor” I discuss a recent study confirming that vitamin D reduces cancer deaths. But before I do that, I will cover what I call “Vitamin D Metabolism 101” to put this week’s topic into context. Later in the article, I will discuss why vitamin D studies are so confusing.

Vitamin D Metabolism 101

There are two things you need to know about vitamin D metabolism to understand today’s article:

Vitamin D occurs in two forms, D3 and D2. Vitamin D3 is the form of vitamin D that our body makes when sunlight hits our skin. Vitamin D2 is a structurally similar analog derived from yeast. For years we thought that vitamin D3 and D2 were equivalent. Vitamin D2 was less expensive, so it was one most often used in supplements.
Vitamin D is inactive. It needs to be activated by the body. It is first converted to 25-hydroxyvitamin D, which is the most abundant form of vitamin D in the bloodstream. It is then taken up by our cells and converted to 1,25-dihydroxyvitamin D, which is the active form. There are two things you need to know about this.
- Since 25-hydroxyvitamin D is found in the blood, it is used as a marker to determine the vitamin D status in the body.
- Recent studies suggest that vitamin D3 is more readily activated than vitamin D2, so it has become the preferred choice for supplementation. The result of this recent conversion from D2 to D3 means that older studies on vitamin D supplementation were primarily done with D2 while newer studies were primarily done with D3.

How Was The Study Done?

This study (Y Zhang et al, BMJ, 366:I4673, 2019 ) was a meta-analysis of 52 clinical trials with 75,454 participants looking at the relationship between vitamin D supplementation cancer deaths, heart disease deaths, and deaths due to any cause.

All the clinical trials were intervention studies in which vitamin D supplementation was compared to either a placebo or no treatment. All participants were adults over the age of 18 and without any pre-existing health conditions. The meta-analysis excluded studies if:

Any participants had pre-existing health conditions.
Any participants were pregnant or lactating women.
Calcium was included along with vitamin D unless both the treatment and placebo groups were given the same amount of calcium.

Does Vitamin D Supplementation Reduce Cancer Deaths?

The results of the study were:

Vitamin D supplementation reduced cancer deaths by 16%. This difference was statistically significant. And:
- This effect was only seen with vitamin D3 supplementation, not with vitamin D2 supplementation.
- The reduction in cancer deaths by vitamin D was only seen in clinical trials that lasted more than 3 years but was not seen in shorter clinical trials.
Vitamin D supplementation did not reduce heart disease deaths. However:
- Weaknesses in the clinical trials included in this meta-analysis made it virtually impossible to determine whether vitamin D supplementation influenced heart disease deaths or not.
Vitamin D supplementation did not significantly reduce death from all causes. However:
- Death from all causes was significantly less in studies using vitamin D3 than in studies in studies using vitamin D2.
- Death from all causes was significantly lower in clinical trials with a longer duration.

Why Are Vitamin D Studies So Confusing?

[Note: This section is a bit technical, so if you aren’t really interested in why vitamin D studies are confusing, you can just skip this section.]

To understand why vitamin D studies are so confusing, it is important to look at vitamin D research from a historical perspective.

Vitamin D research, like most nutrition research, starts with association studies. Association studies have suggested that vitamin D deficiency significantly increases the risk of heart disease and cancer and slightly increased the risk of death from any cause. However, association studies have their strengths and weaknesses. For example:

Strengths:

Association studies can follow large groups of people for a long time.
Association studies are particularly good at identifying the long-term effects of nutritional patterns (such as vitamin D deficiency) on health outcomes.

Weaknesses:

Association studies cannot prove cause and effect, so they are usually followed by intervention studies, such as the ones included in this meta-analysis.

However, intervention studies and this meta-analysis also have their own strengths and weaknesses.

Strengths: The strengths of this meta-analysis are the sample size (52 clinical trials, 75,454 participants) and the rigorous criteria for inclusion of studies in the meta-analysis.

Weaknesses: There are three kinds of weaknesses associated with this study.

Weaknesses of Meta-Analysis Studies: A meta-analysis increases statistical power by combining multiple studies. However, these studies do have weaknesses. For example:

- The strength of the meta-analysis is only as good as the strength of the individual studies that go into it. This is the “garbage in – garbage out” phenomenon.

- The individual studies use different amounts of vitamin D for different lengths of time. So, this meta-analysis is unable to tell you how much supplemental vitamin D would be required to lower your cancer risk.

Weaknesses of Intervention Studies: Double-blind, placebo-controlled intervention studies are considered the “gold standard” for evidence-based medicine. However, they also have their own weaknesses.

- They are usually small. This limits their statistical power to see small effects.
- They are usually short.
  - This is a problem for studies looking at disease outcomes because most major diseases like heart disease or cancer develop over decades. Intervention studies like the ones included in this meta-analysis are simply too short to determine whether vitamin D supplementation could prevent those diseases.
  - It is also a problem for heart disease deaths because they often occur a decade or more after diagnosis. Thus, it is not surprising that the intervention studies included in this meta-analysis have failed to confirm an association between vitamin D and heart disease deaths.
  - However, most cancer deaths occur within the first 2-5 years after diagnosis. So, it is not surprising that intervention studies lasting 3 years or more have been able to confirm an association between vitamin D and cancer deaths.
Weaknesses of Studies With Popular Supplements: Once the benefits of certain nutrients show up in the headlines, people start taking those supplements. This has become a big problem for studies with vitamin D and omega-3 fatty acids. For example:
- > 75% of Americans take a multivitamin with vitamin D, and an additional 18% of adults over 50 also take a vitamin D supplement.
- In this meta-analysis more than half of the participants had a baseline 25-hydroxyvitamin D level of > 50 nmol/L, which the NIH considers to be adequate, prior to supplementation.

That means most of these studies were not asking whether correcting a vitamin D deficiency reduced the risk of death. They were asking whether giving a vitamin D supplement to someone whose vitamin D status was already adequate had any additional benefit. In this context:
- Previous association studies have suggested that a 25-hydroxyvitamin D level of 50 nmol/L is enough to reduce heart disease deaths. Since most of the participants in the clinical trials included in this study started with this level prior to supplementation, it is not surprising that this study found no benefit of vitamin D supplementation on heart disease deaths.
- However, previous association studies have suggested that a 25-hydroxyvitamin D level of 75 nmol/L or greater is required to reduce cancer deaths. Thus, it is not surprising that this and other studies have been able to show that vitamin D supplementation reduces cancer deaths.

In short, these weaknesses in intervention studies have made it virtually impossible to determine whether vitamin D supplementation influences heart disease deaths. Unfortunately, a meta-analysis like this one is only as good as the intervention studies that go into it. This is the “garbage in – garbage out” phenomenon.

However, those weaknesses did not apply to cancer deaths. This and other studies make a strong case that vitamin D supplementation does reduce cancer deaths.

What Does This Study Mean For You?

Association studies have suggested that vitamin D deficiency significantly increases the risk of heart disease and cancer and slightly increased the risk of death from any cause.

This study confirms vitamin D supplementation significantly decreases cancer deaths as predicted from association studies. This observation is strengthened by two other major clinical studies in recent months that have come to the same conclusion. I reported on one of them in a recent issue of “Health Tips From The Professor.”
This study does not indicate an optimal dosage, but the recent VITAL study) reported that 2,000 IU of vitamin D/day was effective at reducing the risk of cancer deaths.
The authors of this study concluded that vitamin D supplementation has no effect on heart disease deaths. However:
It would be more accurate to say that weaknesses in the design of the intervention trials included in their study made it virtually impossible to determine whether vitamin D supplementation influenced heart disease deaths.
To adequately assess whether vitamin D reduced heart disease deaths one would need to start with a population that was deficient in vitamin D and supplement with vitamin D for 5 years or more. That kind of study has not been performed.
The data on whether vitamin D reduces the risk of dying from any cause is less clear.
This study reported that vitamin D supplementation decreased the risk of death from any cause by a non-significant 2%.
Two other recent meta-analyses reported that vitamin D supplementation did have a significant effect on the risk of dying from any cause. However, the risk reduction was 3% in one study and 4% in the other study.
Clearly, vitamin D supplementation is not going to help you live to 100.

The Bottom Line

Previous association studies have suggested that vitamin D deficiency significantly increases the risk of heart disease and cancer and slightly increased the risk of death from any cause.

A recent meta-analysis of 52 clinical trials with 75,454 participants tested those predictions by looking at the effect of vitamin D supplementation on cancer deaths, heart disease deaths, and deaths due to any cause. All the clinical trials were intervention studies in which vitamin D supplementation was compared to either a placebo or no treatment. All participants were adults over the age of 18 and without any pre-existing health conditions.

The results of this meta-analysis were:

Vitamin D supplementation reduced cancer deaths by 16%. This difference was statistically significant. And:
This effect was only seen with vitamin D3 supplementation, not with vitamin D2 supplementation.
The effect of vitamin D supplementation on cancer deaths is strengthened by two other major clinical studies in recent months that have come to the same conclusion.
This study did not indicate an optimal dosage, but the recent VITAL study reported that 2,000 IU of vitamin D/day was effective at reducing the risk of cancer deaths.
Vitamin D supplementation did not reduce heart disease deaths. However:
Weaknesses in the clinical trials included in this meta-analysis made it virtually impossible to determine whether vitamin D supplementation influenced heart disease deaths or not.
Vitamin D supplementation did not significantly reduce death from all causes. However:
Death from all causes was significantly less in studies using vitamin D3 than in studies using vitamin D2.
Death from all causes was significantly lower in clinical trials with a longer duration.

For more details on the study and what it means for you, read the article above. Also, if you would like to understand why there is so much confusion about vitamin D’s health benefits, it is also discussed in 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.

Are Vitamin D Supplements Worthless?

October 30, 2018 by Dr. Steve Chaney

Are We Asking The Right Question?

Author: Dr. Stephen Chaney

We have been told that vitamin D is a miraculous “must have” vitamin. We have been told it’s not just important for healthy bones. It’s also important for a strong immune system, heart health, protection from cancer, and many other health benefits. We have been told that we should get our 25-hydroxy vitamin D levels tested and supplement with extra vitamin D if they are low.

Now, the latest headlines are saying all of that is wrong. They are telling us vitamin D supplements do not improve bone density or protect against falls and bone fractures. They are telling us to forget all the other claimed benefits of vitamin D. Those claims have been disproved. Forget about the 25-hydroxy vitamin D tests. They are a waste of money.

What is the truth? Why is it so confusing? Are vitamin D supplements worthless? Let me guide you through the claims and counterclaims so you can discover the truth for yourself.

How Did Vitamin D Become So Popular?

Let’s start with a brief history of vitamin D. It all started with the industrial revolution in Northern Europe. Suddenly, children and adults in the large cities were spending the bulk of their waking hours in dark factories rather than outdoors on the farm. They were already living in northern latitudes where sunlight was weak during the winter months. To make matters worse pollution from the factories was creating a haze that blocked the sunlight.

That lead directly to the discovery that sunlight was crucial to our body’s ability to synthesize vitamin D and that vitamin D was essential for building strong bones. The solution to the public health crisis of rickets and osteomalacia was to fortify dairy products with vitamin D. The almost universal adaptation of vitamin D fortification virtually eliminated rickets and osteomalacia except in association with certain rare diseases. The two important lessons learned from this experience were:

Vitamin D is essential for healthy bone formation.
Vitamin D supplementation improves bone health for individuals who are deficient in vitamin D

As we discuss the latest findings, we need to keep in mind that these fundamental principles have not changed.

In the late 20^th century our understanding of vitamin D took another leap with the discovery that vitamin D receptors were not restricted to bone cells. Almost every cell in our body contained vitamin D receptors. That lead to studies showing that people with low vitamin D intakes were more likely to experience heart disease, cancer, some autoimmune diseases, and infectious diseases such as flu than people with high vitamin D intakes.

The final leap in our understanding of vitamin D took place when the medical profession started routinely testing blood levels of 25-hydroxy vitamin D. That is when we discovered that some people who appeared to have adequate intake of vitamin D and/or adequate exposure to sunlight had low blood levels of 25-hydroxy vitamin D. Furthermore, follow-up studies showed that low 25-hydroxyvitamin D levels correlated with an increased risk of heart disease, cancer, and infectious disease. The important lessons learned from these experiments were:

Vitamin D deficiency is associated with increased risk of multiple diseases.
25-hydroxy vitamin D tests are the best way to measure vitamin D deficiency.

Once again, these fundamental principles have not changed.

What Did The Study Show?

The study (MJ Bolland et al, Lancet Diabetes Endocrinology 2018) behind the headlines was a meta-analysis of 81 randomized, placebo-controlled studies with a total of 53,537 subjects that looked at the effect of vitamin D supplementation in elderly populations on bone mineral density, bone fractures, and falls.

The meta-analysis only included studies in which vitamin D intake was the sole variable. In many cases the subjects were not taking a calcium supplement. If they were taking a calcium supplement, both the vitamin D group and placebo group were taking the same amount of calcium.

The results were unequivocal. In this study vitamin D supplementation had no effect on bone mineral density, bone fractures, or falls in elderly populations. The authors concluded “There is little justification to use vitamin D supplements to maintain or improve musculoskeletal health.”

Is this conclusion justified? Let’s put the findings of this study into a broader perspective.

Are We Asking The Right Questions?

Before throwing out our vitamin D supplements let’s ask whether this study is asking the right question. I have covered this topic in detail in my new book “Slaying The Supplement Myths” (https://slayingthesupplementmyths.com) with respect to similar studies that had called into question the value of calcium supplements for bone health. Let me cover the highlights here.

In my book I created the graphic on the right to put the question of who benefits from supplementation into perspective. For the purposes of this discussion, I will just focus on poor diet (or, in the case of vitamin D, poor exposure to sunlight). As I discussed above, science shows that people who are not getting enough vitamin D from diet and sunlight benefit from vitamin D supplementation. Unfortunately, vitamin D enthusiasts and some supplement companies have muddied the waters by going beyond what good science shows and suggesting or implying that everyone will benefit from vitamin D supplementation.

This is part of the problem. Once you have created a paradigm that everyone will benefit from vitamin D supplementation, that paradigm is easy to disprove. If someone already has adequate, or nearly adequate, levels of 25-hydroxy vitamin D, would we expect additional vitamin D to make a difference? Of course not, but that is exactly the question the most recent study was asking.

In discussing the limitations of their study, the authors said: “It is possible that trials of populations with low baseline 25-hydroxy vitamin D might produce different results because only 4 trials, involving 831 participants (1.6% of all participants), reported mean baseline 25-hydroxy vitamin D levels lower than 25 nmol/L (the level indicating vitamin D deficiency).

In other words, the study did not measure the effect of vitamin D supplementation for people who were vitamin D deficient. The only take-home lesson from this study is that people with adequate, or near adequate, vitamin D status do not benefit from vitamin D supplementation. That is a “no-brainer.”

Vitamin D And A Bone Healthy Lifestyle

The other glaring deficiency of this study is that it was only measuring the effect of vitamin D on bone health. They purposely excluded any other factor that might influence bone health. That was a fatal flaw because healthy bone requires a holistic approach, not individual nutrients. In my book Slaying the Supplement Myths I refer to this as a “bone healthy lifestyle.”

The most important feature of a “bone healthy lifestyle” is this:

Calcium, vitamin D, and resistance (weight bearing) exercise are all essential for healthy bones.
However, none of them is sufficient by itself. You need all three. You need a holistic approach if you wish to build strong bones.

Simply put, that means unless you include adequate calcium and exercise there is no reason to expect vitamin D supplementation to help build strong bones. Unfortunately, none of the studies included in the recent meta-analysis took a holistic approach to bone health. Some included calcium, but many didn’t. Resistance exercise was never considered. The studies were doomed to failure.

When you include flawed studies in your meta-analysis, you have what computer programmers call “Garbage in. Garbage out.” A meta-analysis can never be stronger than the individual studies it includes.

Other features of a “bone healthy lifestyle” include:

We need more than calcium and vitamin D for strong bones. We need magnesium, zinc, copper, manganese, vitamin C and vitamin K. If we are deficient in any of these, calcium will not be utilized as efficiently.
The foods we eat are also important. Our bones serve as a buffer system to keep our bodies slightly alkaline. Every time we eat acid-forming foods a little bit of bone is dissolved to neutralize the acid. For optimal bone health we need to minimize acid-forming foods and eat more alkaline-forming foods. That means we need to avoid sodas, sweets and refined grains. We also need to minimize meats, eggs, and dairy. Instead, we should focus on fruits, vegetables, peas, beans, lentils, seeds, and nuts.
Beware of drugs. The list of common medications that dissolve bones is a long one. Some of the worst offenders are anti-inflammatory steroids such as cortisone and prednisone, drugs to treat depression, drugs to treat acid reflux, and excess thyroid hormone. I am not suggesting that you should avoid properly prescribed medications. I would suggest you ask your doctor or pharmacist whether the drugs you are taking adversely affect bone density. If they do, you should pay a lot more attention to the other aspects of a “bone healthy lifestyle.”

Are Vitamin D Supplements Worthless?

Now we can come back to the question “Are vitamin D supplements worthless?” as the recent headlines have suggested. If you phrase the question as “Does everyone benefit from vitamin D supplementation?” or “Is vitamin D supplementation alone sufficient to build strong bones?” the answer is a clear no.

However, those are the wrong questions. If you ask: “Does vitamin D supplementation benefit people who are vitamin D-deficient?” the answer is a clear yes. If you ask: “Does a holistic approach that includes resistance exercise, adequate calcium, and adequate vitamin D improve bone health?” the answer is likely to be yes as well.

What about the headlines claiming that vitamin D is also worthless for strengthening the immune system and reducing the risk of heart disease, cancer, and auto-immune diseases? The studies on which these claims are based suffer from the same flaws. They are asking the same wrong questions.

My recommendations:

Have your blood levels of 25-hydroxy vitamin D tested on a regular basis. I have them tested each year when I get my physical.
If your blood levels of 25-hydroxy vitamin D are below 25 nmol/L (which the NIH considers deficient), you are likely to benefit from vitamin D supplementation. If they are above 50 nmol/L (which the NIH considers sufficient), vitamin D supplementation is unlikely to provide additional benefit. However, that level of vitamin D doesn’t guarantee that you will have strong bones. You also need sufficient calcium and resistance exercise.
If your blood levels are in the insufficient range (between 25 nmol/L and 50 nmol/L), the situation is more complicated. If you are close to 50 nmol/L, you may benefit slightly from adding a vitamin D supplement, but the benefit will be too small to show up in a clinical study such as the one that resulted in the recent headlines. My advice is to look at your diet and medication use. If they put you at risk for low bone density, my recommendation would be to add a vitamin D supplement – along with adequate calcium and resistance exercise, of course. If you are closer to 25 nmol/L, you will likely benefit from a vitamin D supplement along with adequate calcium and exercise.
Don’t think of vitamin D supplementation as a “magic bullet” that will solve all your ills. Instead, think of it as just one component of a holistic approach to a bone healthy lifestyle.

The Bottom Line

A recent meta-analysis concluded that vitamin D supplementation did not improve bone mineral density, reduce bone fractures, or reduce falls in the elderly. While this conclusion was definitive, the study was asking the wrong questions.

We know that vitamin D improves bone health for people who are vitamin D-deficient. However, only 1.6% of the people in this study were vitamin D-deficient at the beginning of the study. That means the study was really asking: “If people have adequate, or near adequate, vitamin D status, does vitamin D supplementation provide any additional benefit?” The answer to that question is a “no-brainer.” There is no reason to expect that additional vitamin D would provide benefit.
We know that while vitamin D is essential for building strong bones, it is not sufficient by itself. Strong bones require a holistic approach that includes resistance exercise, adequate calcium, and adequate vitamin D. However, this study only looked at the effect of vitamin D on bone health. Calcium and exercise were excluded from consideration. That means the study was really asking: “Is vitamin D a “magic bullet” that can build strong bones by itself?” Again, there is no reason to expect vitamin D to provide much benefit under those conditions.

My recommendations:

Have your blood levels of 25-hydroxy vitamin D tested on a regular basis. I have them tested each year when I get my physical.
If your blood levels of 25-hydroxy vitamin D are low, you are likely to benefit from vitamin D supplementation. If they are already optimal, vitamin D supplementation is unlikely to provide additional benefit.
Don’t think of vitamin D supplementation as a “magic bullet” that will keep your bones strong by itself. Instead, think of it as just one component of a holistic “bone healthy lifestyle.”

For more details and to see my detailed 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.