Do Bad Genes Doom You To Bad Health?

October 1, 2024 by Dr. Steve Chaney

The Influence Of Genetics And Diet On Type 2 Diabetes

Author: Dr. Stephen Chaney

Does it ever feel like you have drawn the short straw?

Everyone in your family has succumbed to heart disease, diabetes, or cancer at a young age. Are you doomed to the same fate?

You ordered a DNA test. It sounded like fun. But when the gene report came back it said you had a “bad” genetic profile. You were told you are at high risk of diabetes, heart attack, stroke, cancer, or dementia. Are you doomed to a short and sickly life?

In both cases, you are probably wondering, “Is there anything I can do to improve my odds of a healthy life? What if I lost some of those extra pounds, exercised more, and ate a healthier diet? Would that make a difference?”

The study (J Merino et al, PLoS Medicine 19(4): e1003972, April 26, 2022) I will describe today was designed to answer these questions.

But before I describe the study, I should probably cover what I call Genetics 101: “How Genes Affect Your Health”.

Genetics 101: How Genes Affect Your Health

If you studied genetics in school, you probably learned about diseases like sickle cell anemia, which is caused by a single mutation in a single gene. If you get two copies of the “bad” gene, you will have sickle cell anemia. If you get one copy of the “bad” gene and one copy of the normal gene, you have sickle cell trait, which is much less severe.

Simply put, you either have the disease or you don’t. It’s dependent on your genetics, and you can’t do much about it.

If you know someone who has been treated for breast cancer, you are probably familiar with a more complex relationship between genetics and health. There are several “bad” genes that increase the risk of breast cancer. And knowing which gene is involved is important for selecting the best treatment regimen.

But most of the diseases that shorten our lives (like diabetes, heart disease, most cancers, and dementia) are what we call polygenetic diseases. Simply put, that means that there are dozens of genes that increase the risk of these diseases. Each gene makes a small contribution to the increased risk. So, we can only measure the genetic contribution to these diseases by measuring hundreds of mutations in dozens of genes, something called a polygenetic risk score.

The study I will be describing today looked at the relative effect of genetics (measured as the type 2 diabetes polygenic risk score) and diet quality (measured as the Alternative Healthy Eating Index (AHEI)) on the risk of developing type 2 diabetes.

How Was This Study Done?

The data for this study were obtained from 3 long-term clinical studies conducted in the United States – the Nurses’ Health Study (121,700 participants), the Nurses’ Health Study II (116,340 participants), and the Health Professionals Follow-Up Study (51,529 participants).

These studies measured lifestyle factors (including diet) every 4 years and correlated them with disease outcomes over 20+ years.

The study I will be discussing today was performed with 35,759 participants in these 3 studies for whom DNA sequencing data was available.

The DNA sequence data were used to generate a type 2 diabetes polygenic risk score for each participant in this study.

Food frequency questionnaires obtained every 4 years in these studies were used to calculate the Alternative Healthy Eating Index (AHEI) score for each participant.

- The AHEI is based on higher intake of fruits, whole grains, vegetables, nuts and legumes, polyunsaturated fatty acids, long-chain omega-3 fatty acids, moderate intake of alcohol, and lower intake of red and processed meats, sugar sweetened drinks and fruit juice, sodium, and trans-fat).

The investigators used these measurements to estimate the relative effect of genetics and diet quality on the risk of developing type 2 diabetes.

The Influence Of Genetics And Diet On Type 2 Diabetes

The participants were divided into low, intermediate, and high genetic risk based on their type 2 diabetes polygenic risk score.

Compared with low genetic risk:

Intermediate genetic risk increased the risk of developing type 2 diabetes by 26%.

High genetic risk increased the risk of developing type 2 diabetes by 75%.

Put another way, each 1 standard deviation increase in the polygenetic risk score:

Increased the risk of developing type 2 diabetes by 42%.

Simply put, bad genes can significantly increase your risk of developing type 2 diabetes. That’s the bad news. But that doesn’t mean you should think, “Diabetes is in my genes. There is nothing I can do.”

The investigators also divided the participants into those who had a high-quality diet, those who had an intermediate quality diet, and those who had a low-quality diet based on their AHEI (Alternative Healthy Eating Index) score.

Finally, they divided the participants into groups depending on their BMI, a measure of obesity.

Compared to an obese person consuming a low-quality diet, a lean person consuming a high-quality diet:

Reduced their risk of developing type 2 diabetes by around 43% for each category of genetic risk.

More specifically, a lean person consuming a high-quality diet reduced their risk of developing type 2 diabetes:

- By 41% if they were at low genetic risk.

- By 50% if they were at intermediate genetic risk.

- By 38% if they were at high genetic risk.

The investigators then made a statistical adjustment to remove BMI from their calculations, so they could focus on the effect of diet alone on the risk of developing type 2 diabetes.

Compared to a low-quality diet, a high-quality diet:

Reduced the risk of developing type 2 diabetes by around 33% for each category of genetic risk.

More specifically, a high-quality diet reduced the risk of developing type 2 diabetes:

- By 31% for those at low genetic risk.

- By 39% for those at intermediate genetic risk.

- By 29% for those at high genetic risk.

Looking at it another way:

When people at high genetic risk consumed a high-quality diet, their risk of developing type 2 diabetes was only 13% higher than people at intermediate genetic risk who consumed a low-quality diet (such as the typical American diet).

When people at intermediate genetic risk consumed a high-quality diet, their risk of developing type 2 diabetes was 5% less than people at low genetic risk who consumed a low-quality diet.

Simply put:

If you are at intermediate genetic risk, a high-quality diet may completely reverse your risk of developing type 2 diabetes.

If you are at high genetic risk, a high-quality diet can partially reverse your risk of developing type 2 diabetes.

In short, the good news is that bad genes do not doom you to type 2 diabetes.

The investigators did not provide similar information for the effect of an ideal weight on the risk of developing type 2 diabetes, but it is likely that the combination of diet plus weight management would result in an even more significant reduction in risk of developing type 2 diabetes for individuals in the even the highest risk category.

The authors concluded, “These data provide evidence for the independent associations of genetic risk and diet quality with incident type 2 diabetes and suggest that a healthy diet is associated with lower diabetes risk across all levels of genetic risk.”

Do Bad Genes Doom You To Bad Health?

At the beginning of this article I posed the question, “Do bad genes doom you to bad health?”

Based on this study, the good news is that bad genes don’t doom you type 2 diabetes. And just because most of your relatives are diabetic doesn’t mean that must be your fate.

This study shows that a healthy diet significantly reduces your risk of developing type 2 diabetes at every genetic risk level.

And the study suggests that a healthy diet plus a healthy weight is even more beneficial at reducing your risk of type 2 diabetes.

While not included in this study, other studies have shown that exercise also plays a role in reducing type 2 diabetes risk.

None of this information is new. What is new is that a healthy diet is equally beneficial at reducing type 2 diabetes risk even in individuals with a high genetic risk of developing the disease. Simply put, you can reverse the effects of bad genes.

“And what is this magic diet?”, you might ask. In this study, it was based on AHEI score. Someone with a high AHEI score consumes:

Lots of fruits, whole grains, vegetables, nuts and legumes, polyunsaturated fatty acids, and long-chain omega-3 fatty acids.

Moderate or no amounts of alcohol.

Little or no red and processed meats, sugar sweetened drinks, fruit juices, sodium, and foods with trans-fat.

Any whole food, primarily plant-based diet from vegan to Mediterranean or DASH fits the bill.

Finally, while this study focused just on type 2 diabetes, other studies have come to similar conclusions for other diseases.

Should You Get Your DNA Tested?

If you are looking for guidance on how to reduce your risks, the answer is, “No”. In this study, the same diet and lifestyle changes lowered the risk of type diabetes at every genetic risk level. Despite what some charlatans may tell you, there is no special diet or magic potion for people with a high genetic risk for developing type 2 diabetes.

If you are looking for motivation, the answer may be, “Yes”. If knowing you are at high risk makes it more likely that you will make the diet and lifestyle changes needed to lower your risk of type 2 diabetes, a DNA test may be just what you need

The Bottom Line

If a serious disease runs in your family or if you have had your DNA tested and found out you are at high risk for some disease, you are probably wondering whether there is anything you can do or whether your bad genes have doomed you to a short and sickly life.

A recent study answered that question for type 2 diabetes. It showed a healthy diet significantly reduces the risk of type 2 diabetes even in people at high genetic risk of developing the disease.

Other studies have come to similar conclusions for other diseases. In short, bad genes don’t doom you to bad health.

For more details about the study and what it means 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.

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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

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About The Author

Dr. Chaney has a BS in Chemistry from Duke University and a PhD in Biochemistry from UCLA. He is Professor Emeritus from the University of North Carolina where he taught biochemistry and nutrition to medical and dental students for 40 years. Dr. Chaney won numerous teaching awards at UNC, including the Academy of Educators “Excellence in Teaching Lifetime Achievement Award”. Dr Chaney also ran an active cancer research program at UNC and published over 100 scientific articles and reviews in peer-reviewed scientific journals. In addition, he authored two chapters on nutrition in one of the leading biochemistry text books for medical students.

Since retiring from the University of North Carolina, he has been writing a weekly health blog called “Health Tips From the Professor”. He has also written two best-selling books, “Slaying the Food Myths” and “Slaying the Supplement Myths”. And most recently he has created an online lifestyle change course, “Create Your Personal Health Zone”. For more information visit https://chaneyhealth.com.

For the past 45 years Dr. Chaney and his wife Suzanne have been helping people improve their health holistically through a combination of good diet, exercise, weight control and appropriate supplementation.

Can Lifestyle Overcome Bad Genes?

January 31, 2023 by Dr. Steve Chaney

Lifestyle, Genetics, And Dementia Risk

Author: Dr. Stephen Chaney

Alzheimer’s disease and other forms of dementia are among the most feared diseases of aging. What use is it to have a healthy body, a loving family, and a successful career if you can’t remember any of it? You should be able to enjoy your Golden years, not see them slip through your fingers.

If you have a family history of dementia or have sent your DNA off for testing and learned you are genetically predisposed to dementia, you are probably worried.

Perhaps the scariest thing about Alzheimer’s is that the medical community has no answers. There are no drugs to prevent or cure Alzheimer’s and brain transplants are out of the question. Some medical professionals will tell you nothing can be done, but is that true?

Before I answer that question let me share a fictional story because it provides a clue. In 1997, when I was still a relatively young scientist, I saw a film called GAATACA. [If you are looking for an entertaining film to watch, it is still available on some streaming services.]

This film envisioned a future society in which parents had their sperm and eggs sequenced so that their children would be genetically perfect. In that society the term “love child” had been redefined as a child who had been conceived without prior DNA sequencing.

The hero of this film was, of course, a love child. He was born with a genetic predisposition for heart disease. He was considered inferior, a second-class citizen of this future world.

Without giving away the plot of the film (I don’t want to spoil the enjoyment for you if you are thinking of watching it), he overcame his genetic inferiority. With a strict regimen of diet and physical fitness he became stronger and healthier than many of his genetically perfect peers.

This is when I first began to realize that our genes do not have to determine our destiny. We have the power to overcome bad genetics. We also have the power to undermine good genetics.

With that in mind, let’s return to Alzheimer’s. Studies have suggested that a healthy lifestyle can help reduce your risk of developing Alzheimer’s and other forms of dementia. But what about genetics? Will a healthy lifestyle only reduce your risk of dementia if your genetic risk is low, or will it be equally effective when your genetic risk is high? Can lifestyle overcome genetics?

The current study (A Tin et al, Neurology, 99: e154-e163, 2022) was designed to answer these questions.

How Was This Study Done?

This study included 11,561 participants from the Atherosclerosis Risk In Communities (ARIC) study. The ARIC study recruited middle-aged adults (average age of 54) from both urban and rural areas of the United States and followed them for 26 years. The participants were 57% female and 53% white.

Simply put, the study was designed to look at the effect of a healthy lifestyle on the genetic risk of developing dementia.

A healthy lifestyle was defined based on something called “Life’s Simple 7” (LS7) score.

The LS7 score was developed by the American Heart Association to define the effect of lifestyle on the risk of developing heart disease. However, it works equally well for defining the effect of lifestyle on risk of developing dementia.

The LS7 score consists of 7 modifiable health factors.

- The factors are diet, physical activity, BMI (a measure of obesity), smoking, total cholesterol, blood pressure, and fasting blood glucose.

The data for deriving the LS7 scores were derived from data gathered from each participant when they enrolled in the ARIC study.

- Diet was assessed by a 66-item food frequency questionnaire.

- Physical activity and smoking were assessed in separate questionnaires.

- BMI, blood pressure, total cholesterol, and fasting blood glucose were measured during a visit to a designated clinic at the beginning of the study.

Each modifiable health factor was separated into 3 categories (ideal, intermediate, and poor) and the highest score was assigned to the ideal category. The LS7 score was the sum of the scores from all 7 modifiable health factors.

Genetic risk of developing dementia was defined based on something called “The Genetic Risk Score” (GRS).

We have known for years that individuals of European descent who have the APOE ɛ4 gene variant have a 2 to 5-fold increased lifetime risk of developing dementia.

In recent years scientists have discovered several additional gene variants that increase the risk of dementia.

These have been combined with APOE ɛ4 to create a Genetic Risk Score for dementia.

The Genetic Risk Score for each participant was determined by DNA sequencing at the beginning of the study, with the highest score indicating the greatest risk for developing dementia.

The onset and severity of dementia were determined based on 7 clinic visits during the study.

Questionnaires were administered at each visit to assess self-reported dementia symptoms.

Cognitive tests were administered at visits 2 and 4.

Detailed cognitive and functional assessments were conducted at visits 5, 6, and 7.

The data were reviewed by an expert committee of physicians and neuropsychologists to determine dementia status.

Lifestyle, Genetics, And Dementia Risk

At the end of the 26-year study:

When participants with the highest Genetic Risk Scores were compared to those with the lowest Genetic Risk Scores:

- European American participants were 2.7-fold more likely to develop dementia.

- African American participants were 1.55-fold more likely to develop dementia.

When participants with the highest LS7 (healthy lifestyle) scores were compared to those with the lowest LS7 scores:

- European American participants were 40% less likely to develop dementia.

- African American participants were 17% less likely to develop dementia.

- A healthy lifestyle decreased the risk of developing dementia to a comparable extent at all levels of genetic risk for dementia.

The authors concluded, “Higher LS7 scores [a measure of a healthy lifestyle] are largely associated with a lower risk of incident dementia across strata of genetic risk [at all levels of genetic risk], supporting the use of LS7 [a healthy lifestyle] for maintaining brain health and offsetting genetic risk. More studies with larger study populations are needed…”

I should briefly comment on why African Americans were less responsive to both genetic risk and a healthy lifestyle than European Americans. The reasons for these discrepancies are not known, but:

There are socioeconomic factors and health disparities that increase the risk of dementia that are not included in the LS7 score.
A recent study has identified genetic risk factors for dementia that are unique to African Americans that are not included in the genetic risk score used in this study.

Can Lifestyle Overcome Bad Genes?

Dr. James Watson, who was co-discoverer of the DNA double helix and was heavily involved in the sequencing of the human genome, asked that he not be told about his risk of developing Alzheimer’s when his own DNA was sequenced in the early 2000’s. His reasoning was, “Why know the risk if you can’t change it?”

If the study I discussed today is true, you can modify the risk. Your genes don’t have to be your destiny. But is it true?

There is good reason to believe it might be true. Multiple studies have shown that each of the health factors included in LS7 score reduce the risk of developing dementia. However, most of those studies have not looked at the interaction between a healthy lifestyle and genetic risk.

Fortunately, there is another recent study that looked at the interaction between a healthy lifestyle and genetic risk of developing dementia.

This study used a different database (The UK Biobank study which enrolled 500,000 participants) and different criteria for defining a healthy lifestyle (diet, physical activity, smoking, and alcohol use).

However, the conclusions of this study were very similar:

People at high genetic risk were almost twice as likely to develop dementia as those at low genetic risk.

A healthy lifestyle decreased the risk of developing dementia by about 40% for both people at high genetic risk and for people at low genetic risk.

But this study went one step further than the study I discussed in this article. The British study reported that:

People at low genetic risk and an unhealthy lifestyle (the typical American) were just as likely to develop dementia as people at high genetic risk and a healthy lifestyle.

In other words, bad genetics does not doom you to Alzheimer’s and dementia. A healthy lifestyle can cut your risk almost in half. Conversely, good genetics is not a “Get Out of Jail Free” card. You can squander the advantage of good genetics with an unhealthy lifestyle.

And, just like the hero of the movie I discuss at the beginning of this article, a healthy lifestyle may be able to overcome bad genes and make you just as healthy (with respect to the risk of developing dementia) as people with good genes and an unhealthy lifestyle – which includes most Americans.

The Bottom Line

If you have a family history of dementia or have sent your DNA off for testing and learned you are genetically predisposed to dementia, you are probably worried.

Studies have suggested that a healthy lifestyle can help reduce your risk of developing Alzheimer’s and other forms of dementia. But what about genetics? Will a healthy lifestyle only reduce your risk of dementia if your genetic risk is low, or will it be equally effective when your genetic risk is high? Can lifestyle overcome genetics?

A recent study was designed to answer these questions. It found:

When participants with the highest Genetic Risk Scores were compared to those with the lowest Genetic Risk Scores:

- They were 1.5 to 2.7-fold more likely to develop dementia.

When participants with the highest LS7 (healthy lifestyle) scores were compared to those with the lowest LS7 scores:

- They were 17% to 40% less likely to develop dementia.

A healthy lifestyle decreased the risk of developing dementia to a comparable extent at all levels of genetic risk for dementia.

This, and other studies discussed in this issue of “Health Tips For The Professor” suggest that your genes don’t have to determine your destiny. You can overcome bad genes with a healthy lifestyle.

For more details on this 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.

Who Benefits Most From Supplementation?

February 8, 2022 by Dr. Steve Chaney

Supplements Are Part of a Holistic Lifestyle

Author: Dr. Stephen Chaney

The headlines about supplementation are so confusing. Are they useful, or are they a waste of money? Will they cure you, or will they kill you? I feel your pain.

I have covered these questions in depth in my book, “Slaying The Supplement Myths”, but let me give you a quick overview today. I call it: “Who Benefits Most From Supplementation?” I created the graphic on the left to illustrate why I feel responsible supplementation is an important part of a holistic lifestyle for most Americans. Let me give you specific examples for each of these categories.

Examples of Poor Diet

You have heard the saying that supplementation fills in the nutritional gaps in our diets, so what are the nutritional gaps? According to the USDA’s 2020-2025 Dietary Guidelines for Americans, many Americans are consuming too much fast and convenience foods. Consequently, we are getting inadequate amounts of calcium, magnesium, and vitamins A, D, E and C. Iron is considered a nutrient of concern for young children and pregnant women. In addition, folic acid, vitamin B6, and iodine are nutrients of concern for adolescent girls and pregnant women.

According to a recent study, regular use of a multivitamin is sufficient to eliminate all these deficiencies except for calcium, magnesium and vitamin D (J.B. Blumberg et al, Nutrients, 9(8): doi: 10.3390/nu9080849, 2017). A well-designed calcium, magnesium and vitamin D supplement may be needed to eliminate those deficiencies.

In addition, intake of omega-3 fatty acids from foods appears to be inadequate in this country. Recent studies have found that American’s blood levels of omega-3s are among the lowest in the world and only half of the recommended level for reducing the risk of heart disease (K.D. Stark et al, Progress In Lipid Research, 63: 132-152, 2016; S.V. Thuppal et al, Nutrients, 9, 930, 2017; M Thompson et al, Nutrients, 11: 177, 2019). Therefore, omega-3 supplementation is often a good idea.

In previous editions of “Health Tips From the Professor” I have talked about our “mighty microbiome”, the bacteria and other microorganisms in our intestine. These intestinal bacteria can affect our tendency to gain weight, our immune system, inflammatory diseases, chronic diseases such as diabetes, cancer, and heart diseases, our mood—the list goes on and on. This is an emerging science. We are learning more every day, but for now it appears our best chances for creating a health-enhancing microbiome are to consume a primarily plant-based diet and take a probiotic supplement.

Finally, diets that eliminate whole food groups create nutritional deficiencies. For example, vegan diets increase the risk of deficiencies in vitamin B12, vitamin D, calcium, iron, zinc and long chain omega-3 fatty acids. A recent study reported that the Paleo diet increased the risk of calcium, magnesium, iodine, thiamin, riboflavin, folate and vitamin D deficiency (A. Genomi et al, Nutrients, 8, 314, 2016). The Keto diet is even more restrictive and is likely to create additional deficiencies.

Examples of Increased Need

We have known for years that pregnancy and lactation increase nutritional requirements. In addition, seniors have increased needs for protein, calcium, vitamin D and vitamin B12. In previous issues of “Health Tips From the Professor” I have also shared recent studies showing that protein requirements are increased with exercise.

Common medications also increase our need for specific nutrients. For example, seizure medications can increase your need for vitamin D and calcium. Drugs to treat diabetes and acid reflux can increase your need for vitamin B12. Other drugs increase your need for vitamin B6, folic acid, and vitamin K. Excess alcohol consumption increases your need for thiamin, folic acid, and vitamin B6. These are just a few examples.

Vitamin D is a special case. Many people with apparently adequate intake of vitamin D have low blood levels of 25-hydroxy vitamin D. It is a good idea to have your blood 25-hydroxy vitamin D levels measured on an annual basis and supplement with vitamin D if they are low.

More worrisome is the fact that we live in an increasing polluted world and some of these pollutants may increase our needs for certain nutrients. For example, in a recent edition of “Health Tips From the Professor” I shared a study reporting that exposure to pesticides during pregnancy increases the risk of giving birth to children who will develop autism, and that supplementation with folic acid during pregnancy reduces the effect of pesticides on autism risk. I do wish to acknowledge that this is a developing area of research. This and similar studies require confirmation. It is, however, a reminder that there may be factors beyond our control that have the potential to increase our nutritional needs.

Examples of Genetics Influencing Nutritional Needs

The effect of genetic variation on nutritional needs is known as nutrigenomics. One of the best-known examples of nutrigenomics is genetic variation in the methylenetetrahydrofolate reductase (MTHFR) gene. MTHFR gene mutations increase the risk of certain birth defects, such as neural tube defects. MTHFR mutations also slightly increase the requirement for folic acid. A combination of food fortification and supplementation with folic acid have substantially decreased the prevalence of neural tube defects in the US population. This is one of the great success stories of nutrigenomics. Parenthetically, there is no evidence that methylfolate is needed to decrease the risk of neural tube defects in women with MTHFR mutations.

Let me give you a couple of additional examples:

One of them has to do with vitamin E and heart disease (A.P. Levy et al, Diabetes Care, 27: 2767, 2004). Like a lot of other studies there was no significant effect of vitamin E on cardiovascular risk in the general population. But there is a genetic variation in the haptoglobin gene that influences cardiovascular risk. The haptoglobin 2-2 genotype increases oxidative damage to the arterial wall, which significantly increases the risk of cardiovascular disease. When the authors of this study looked at the effect of vitamin E in people with this genotype, they found that it significantly decreased heart attacks and cardiovascular deaths.

This has been confirmed by a second study specifically designed to look at vitamin E supplementation in that population group (F. Micheletta et al, Arteriosclerosis, Thrombosis and Vascular Biology, 24: 136, 2008). This is an example of a high-risk group benefiting from supplementation, but in this case the high risk is based on genetic variation.

Let’s look at soy and heart disease as a final example. There was a study called the ISOHEART study (W.L. Hall et al, American Journal of Clinical Nutrition, 82: 1260-1268, 2005 (http://ajcn.nutrition.org/content/82/6/1260.abstract); W.L. Hall et al, American Journal of Clinical Nutrition, 83: 592-600, 2006) that looked at a genetic variation in the estrogen receptor which increases inflammation and decreases levels of HDL. As you might expect, this genotype significantly increases cardiovascular risk.

Soy isoflavones significantly decrease inflammation and increase HDL levels in this population group. But they have no effect on inflammation or HDL levels in people with other genotypes affecting the estrogen reception. So, it turns out that soy has beneficial effects, but only in the population that’s at greatest risk of cardiovascular disease, and that increased risk is based on genetic variation.

These examples are just the “tip of the iceberg”. Nutrigenomics is an emerging science. New examples of genetic variations that affect the need for specific nutrients are being reported on a regular basis. We are not ready to start genotyping people yet. We don’t yet know enough to design a simple genetic test to predict our unique nutritional needs. That science is 10-20 years in the future, but this is something that’s coming down the road.

What the current studies tell us is that some people are high-risk because of their genetic makeup, and these are people for whom supplementation is going to make a significant difference. However, because genetic testing is not yet routine, most people are completely unaware that they might be at increased risk of disease or have increased nutritional requirements because of their genetic makeup.

Examples of Disease Influencing Nutritional Needs

Finally, let’s consider the effect of disease on our nutritional needs. If you look at the popular literature, much has been written about the effect of stress on our nutritional needs. In most case, the authors are referring to psychological stress. In fact, psychological stress has relatively minor effect on our nutritional needs.

Metabolic stress, on the other hand, has major effects on our nutritional needs. Metabolic stress occurs when our body is struggling to overcome disease, recover from surgery, or recover from trauma. When your body is under metabolic stress, it is important to make sure your nutritional status is optimal.

The effects of surgery and trauma on nutritional needs are well documented. In my book, “Slaying The Supplement Myths”, I discussed the effects of disease on nutritional needs in some detail. Let me give you a brief overview here. It is very difficult to show beneficial effects of supplementation in a healthy population (primary prevention). However, when you look at populations that already have a disease, or are at high risk for disease, (secondary prevention), the benefits of supplementation are often evident.

For example, studies suggest that vitamin E, B vitamins, and omega-3s each may reduce heart disease risk, but only in high-risk populations. Similarly, B vitamins (folic acid, B6 and B12) appear to reduce breast cancer risk in high risk populations.

Who Benefits Most From Supplementation?

With this information in mind, let’s return to the question: “Who benefits most from supplementation? Here is my perspective.

1) The need for supplementation is greatest when these circles overlap, as they do for most Americans.

2) The problem is that while most of us are aware that our diets are not what they should be, we are unaware of our increased needs and/or genetic predisposition. We are also often unaware that we are at high risk of disease. For too many Americans the first indication they have heart disease is sudden death, the first indication of high blood pressure is a stroke, or the first indication of cancer is a diagnosis of stage 3 or 4 cancer.

So, let’s step back and view the whole picture. The overlapping circles are drawn that way to make a point. A poor diet doesn’t necessarily mean you have to supplement. However, when a poor diet overlaps with increased need, genetic predisposition, disease, or metabolic stress, supplementation is likely to be beneficial. The more overlapping circles you have, the greater the likely benefit you will derive from supplementation.

That is why I feel supplementation should be included along with diet, exercise, and weight control as part of a holistic approach to better health.

The Bottom Line

In this article I provide a perspective on who benefits most from supplementation and why. There are four reasons to supplement.

Fill Nutritional gaps in our diet

2) Meet increased nutritional needs due to pregnancy, lactation, age, exercise, many common medications, and environmental pollutants.

3) Compensate for genetic variations that affect nutritional needs.

4) Overcome needs imposed by metabolic stress due to trauma, surgery, or disease.

With this information in mind, let’s return to the question: “Who benefits most from supplementation? Here is my perspective.

A poor diet alone doesn’t necessarily mean you have to supplement. However, when a poor diet overlaps with increased need, genetic predisposition, or metabolic stress, supplementation is likely to be beneficial. The more overlap you have, the greater the likely benefit you will derive from supplementation.

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.

Is DNA Testing Valuable?

October 5, 2021 by Dr. Steve Chaney

What Is The True Value Of DNA Tests?

Author: Dr. Stephen Chaney

DNA testing is hot! DNA testing companies claim they can tell you your disease risk and personalize your diet and supplement program – all based on the sequence of your DNA.

On the other hand, most reputable medical sources say these DNA testing companies overpromise and underdeliver. They tell you that diet, lifestyle, and supplement recommendations based only on your DNA sequence are often inaccurate.

So, what should you believe? At this point you are probably wondering:

Is DNA testing valuable or is it a waste of money?

Is there a way to make DNA testing more accurate?

What is the true value of DNA testing to you, the consumer?

I will consider these 3 questions in my article below. But first let me share two stories about DNA testing, one true and the other fictional.

Perspectives on DNA Testing

When the human genome was first sequenced in 2003, it took 13 years and cost millions of dollars. That was an exciting time. Many of us in the scientific community thought we were on the verge of a revolution in human health and longevity. We would soon be able to tell individuals their risk of developing various diseases.

Even better, we would be able to tell them the kind of diet and supplementation they needed to avoid those diseases. We would be able to personalize our nutritional recommendation for every individual based on their genome – something we called nutrigenomics.

How naive we were! It has turned out to be much more complicated to design personalized nutrition recommendations based on someone’s genome than we ever imagined.

Today an analysis of your genome requires hours and costs less than $200. That represents a tremendous advance in technology. However, we are no closer to being able to make personal nutrition recommendations based on our DNA sequence today than we were 18 years ago.

Why is that? Let me share a fictional story because it provides a clue. In 1997, when I was still a relatively young scientist, I saw a film called GAATACA. [If you are looking for an entertaining film to watch, it is still available on some streaming services.]

The hero of this film was, of course, a love child. He was born with a genetic predisposition for heart disease. He was considered inferior, a second-class citizen of this future world.

This is when I first began to realize that our DNA does not have to be our destiny. We have the power to overcome bad genetics. We also have the power to undermine good genetics.

You might be wondering, “How can this be? Why doesn’t our DNA determine our destiny” I will answer that question in two parts.

First, I will share what experts say about the value of DNA testing.

Then I will put on my professor hat and discuss “Genetics 101 – What we didn’t know in 2003” (When the genome was first sequenced).

Is DNA Testing Valuable?

As I said above, most scientists are skeptical about the ability of DNA testing to predict our ideal diet and supplementation regimens. For example, here are two recent reviews on the current status of DNA testing. [Note: These scientists are using “science speak”. Don’t worry if you don’t understand all the terms. I will explain their message in simpler terms in the next section.]

One review (C Murgia and MM Adamski, Nutrients, 366, 2017) published in 2017 concluded: “The potential applications to nutrition of this invaluable tool [DNA sequencing] were apparent since the genome was mapped…However, fifteen years and hundreds of publications later, the gap between genome mapping and health practice is not yet closed.”

“The discovery of other levels of control, including epigenetics [modifications of DNA that affect gene expression] and the intestinal microbiome complicate the interpretation of genetic data. While the science of nutritional genomics remains promising, the complex nature of gene, nutrition and health interactions provides a challenge for healthcare professionals to analyze, interpret and apply to patient recommendations.”

Another review (M Gaussch-Ferre et al, Advances in Nutrition, 9: 128-135, 2018) published in 2018 concluded: “Overall, the scientific evidence supporting the dissemination of genomic information for nutrigenomic purposes [predicting ideal diet and supplement regimens] remains sparse. Therefore, additional knowledge needs to be generated…”

In short, the experts are saying we still don’t know enough to predict the best diet or the best supplements based on genetic information alone.

Genetics 101 – What We Didn’t Know In 2003

In simple terms the experts who published those reviews are both saying that the linkage between our DNA sequence and either diet or supplementation is much more complex than we thought in 2003 when the genome was first sequenced.

That is because our understanding of genetics has been transformed by two new areas of research, epigenetics and our microbiome. Let me explain.

Epigenetics has an important influence on gene expression. When I was a graduate student, we believed our genetic destiny was solely determined by our DNA sequence. That was still the prevailing viewpoint when the human genome project was initiated. As I said above, we thought that once we had our complete DNA sequence, we would know everything we needed to know about our genetic destiny.

It turns out that our DNA can be modified in multiple ways. These modifications do not change the DNA sequence, but they can have major effects on gene expression. They can turn genes on or turn them off. More importantly, we have come to learn that these DNA modifications can be influenced by our diet and lifestyle.

This is the science we call epigenetics. We have gone from believing we have a genome (DNA sequence) that is invariant and controls our genetic destiny to understanding that we also have an “epigenome” (modifications to our DNA) that is strongly influenced by our diet and lifestyle and can change day-to-day.

2) Our microbiome also has an important influence on our health and nutritional status. Simply put, the term microbiome refers to our intestinal microbes. Our intestinal bacteria are incredibly diverse. Each of us has about 1,000 distinct species of bacteria in our intestines.

Current evidence suggests these intestinal bacteria influence our immune system, inflammation and auto-immune diseases, brain function and mood, and our predisposition to gain weight – and this may just be the tip of the iceberg.

More importantly, our microbiome is also influenced by our diet and lifestyle, and environment. For example, vegetarians and meat eaters have entirely different microbiomes.

Furthermore, the effect of diet and lifestyle on our microbiome also changes day to day. If you change your diet, the species of bacteria in your microbiome will completely change in a few days.

If you are wondering how that could be, let me [over]simplify it for you:

- What we call fiber, our gut bacteria call food.

- Different gut bacteria thrive on different kinds of fiber.

- Different plant foods provide different kinds of fiber.

- Whenever we change the amount or type of fiber in our diet, some gut bacteria will thrive, and others will starve.

- Bacteria grow and die very rapidly. Thus, the species of bacteria that thrive on a particular diet quickly become the predominant species in our gut.

- And when we change our diet, those gut bacteria will die off and other species will predominate.

Finally, our microbiome also influences our nutritional requirements. For example, some species of intestinal bacteria are the major source of biotin and vitamin K2 for all of us and the major source of vitamin B12 for vegans. Other intestinal bacteria inactivate and/or remove some vitamins from the intestine for their own use. Thus, the species of bacteria that populate our intestines can influence our nutritional requirements.

Now that you know the complexity of gene interactions you understand why we are not ready to rely on DNA tests alone. That science is at least 10-20 years in the future. Companies that tell you otherwise are lying to you.

What Is The True Value Of DNA Tests?

By now you are probably thinking that my message is that DNA tests are worthless. Actually, my message is a bit different. What I, and most experts, are saying is that DNA tests are of little value by themselves.

To understand the true value of DNA tests, let me start with defining a couple of terms you may vaguely remember from high school biology – genotype and phenotype.

Genotype is your genes.

Phenotype is you – your health, your weight, and your nutritional needs. Your phenotype is determined by your genes plus your diet and your lifestyle.

With that in mind, let’s review the take-home messages from earlier sections of this article.

The take-home message from the two stories in “Perspectives on DNA Testing” is that our DNA does not have to be our destiny. We have the power to overcome bad genetics. We also have the power to undermine good genetics.

The take-home message from “Genetics 101” is that while the genes we inherit do not change, the expression of those genes is controlled in part by:

- Epigenetic modifications to the DNA. And those epigenetic modifications are controlled by our diet and our lifestyle.

- Our microbiome (gut bacteria). And our microbiome is controlled by our diet and our lifestyle.

Now we are ready to answer the question, “What is the true value of DNA testing?” There are actually two answers to this question. You have probably guessed the first answer by now, but you will be surprised by the second.

DNA testing can only indicate the potential for obesity, the potential for nutritional deficiencies, and the potential for disease. But whether that potential is realized depends on our diet and lifestyle. Therefore, the true value of DNA testing comes from adding a comprehensive analysis of diet and lifestyle to the DNA test results. That includes:

- Questionnaires that assess diet, lifestyle, health goals, and health concerns.

For example, your genetics may indicate an increased need for vitamin D. This is a concern if your vitamin D intake is marginal but may not be a concern if you are getting plenty of vitamin D from your diet, supplementation, and sun exposure.

- Direct measurements of obesity such as height and weight (from which BMI can be calculated) and waist circumference (belly fat is more dangerous to our health than fat stored elsewhere in our body).

For example, most Americans have a genetic predisposition to obesity, but not everyone is obese. If you are overweight or obese, your nutrition and lifestyle recommendations should include approaches to reduce your weight. If not, these recommendations are not needed, even if you have a genetic predisposition to obesity.

- Blood pressure and blood markers of disease risk (cholesterol, triglycerides, and blood sugar).

For example, you may have genetic predisposition to high blood pressure or high cholesterol. If either of these are high, your recommendations should include nutrition and lifestyle approaches to lower them. However, if you are already keeping them under control through diet and lifestyle, no further changes may be necessary.

2) While the scientific community now knows the limitations of DNA testing, this information has not filtered down to the general public. This brings me to the second value of DNA testing. Several recent studies have shown that people are much more likely to follow recommendations based on DNA testing than recommendations based on dietary questionnaires, blood markers of disease, or even recommendations from their physician.

The Bottom Line

DNA testing is hot! DNA testing companies claim they can tell you your disease risk and personalize your diet and supplement program – all based on the sequence of your DNA.

So, what is the true value of DNA testing? To answer that question, we need to know two things:

1) Our DNA is not our destiny. We have the power to overcome bad genetics. We also have the power to undermine good genetics.

2) While the genes we inherit do not change, the expression of these genes is controlled in part by:

- Epigenetic modifications to the DNA. And those epigenetic modifications are controlled by our diet and our lifestyle.

- Our microbiome (gut bacteria). And our microbiome is controlled by our diet and our lifestyle.

With this information in mind, we are ready to answer the question, “What is the true value of DNA testing?” The true value of DNA testing is tw0-fold:

1) It comes from adding a comprehensive analysis of diet and lifestyle to the DNA test results. This includes:

- Questionnaires that assess diet, lifestyle, health goals, and health concerns.

- Direct measurements of obesity such as height and weight (from which BMI can be calculated) and waist circumference (belly fat is more dangerous to our health than fat stored elsewhere in our body).

- Blood pressure and blood markers of disease risk (cholesterol, triglycerides, and blood sugar).

2) In addition, several recent studies have shown that people are much more likely to follow recommendations based on DNA testing than recommendations based on dietary questionnaires, blood markers of disease, or even recommendations from their physician.

For more details and explanations of the statements in “The Bottom Line”, 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 Obesity Begin In Kindergarten?

February 18, 2014 by Dr. Steve Chaney

Is Obesity Caused By Bad Genes Or Bad Lifestyle?

Author: Dr. Stephen Chaney

In past issues of “Health Tips From the Professor” I have shared some common sense weight loss tips. But what if it is all for naught? What if there is nothing you can do about your weight?

You may have seen the headlines suggesting that obesity in kindergarten is a very strong predictor of obesity later in life. If so, you are probably wondering what that means for your kids or grandkids – and what it means for you. You are probably asking questions like:

Should you be worrying about that your toddler’s baby fat?

What can you do as parents and grandparents to protect the ones you love from a lifetime of obesity and all of the health challenges that involves?

Is there anything you can do about overweight and obesity? Are some people just fated to be obese from childhood on?

What Does the Study Actually Show?

This was a very well done study. It followed 7738 children of all socioeconomic classes who were enrolled in kindergarten (mean age 5.6) in the US in 1998 and followed them through the 8^th grade (mean age 14.1) (Cunningham et al, New England Journal of Medicine, 370: 403-411, 2014).

When the children entered kindergarten, 12.4% of them were obese, and another 14.9% of them were overweight. By the time they reached the 8^th grade 20.8% were obese and 17% were overweight. Those results didn’t make the headlines. They are similar to many previous studies.

The results that made the headlines were:

Overweight 5 year olds were 4 times more likely to become obese by age 14 than normal weight 5 year olds.

87% of obese 8^th graders (14 year olds) had a body mass index above the 50^th percentile in kindergarten, and 75% had a body mass index above the 70^th percentile.

Only 13% of overweight 8^th graders had been normal weight (<50^th percentile) in kindergarten, and only 13% of the normal weight 8^th graders had been overweight in kindergarten.

These results are fully consistent with earlier studies showing that overweight toddlers are likely to become overweight teens, and overweight teens are likely to become overweight adults. What was unique about this study (and generated the headlines) was the precision of the statistics.

Does Obesity Begin In Kindergarten?

The answer to that question is clearly yes. However, the more important question is what message we, as responsible health advocates, should be sharing with the general public. Let me break that down to some of the most important questions that you are probably asking.

Is Obesity Caused By Bad Genes Or Bad Lifestyle?

Taken on face value, the results of this study might seem to suggest that genetics is the primary cause of obesity. However, if that is the message we convey to the public, it is likely to simply fuel the perception that most overweight individuals are genetically destined to be obese. There is nothing they can do about it. So, why even bother trying?

However, the authors of the study also noted that the percentage of children aged 6 to 11 who are above the 95% percentile of weight has increased 4-fold between 1963 and 2000. Genetics does not change in a mere 37 years (37 generations maybe). That 4-fold increase in severe childhood obesity is clearly driven by lifestyle changes over the past 30 or 40 years.

While nobody knows the exact percentages, a reasonable interpretation of recent research in this area might be:

10-15% of us are genetically destined to be obese. There is little we can do to change our weight, but a healthy lifestyle can significantly reduce our risk of disease.

10-15% of us are genetically predestined to be lean no matter what we eat (Yes. Your suspicions are true). Once again, lifestyle has relatively little influence on our weight, but a healthy lifestyle can significantly reduce our risk of disease.

The other 70-80% of us are genetically predisposed to become obese if we adapt the typical American lifestyle. For most of us lifestyle choices can make a big difference in our weight as well as our health.

So the answer to this question is BOTH. For most of us, obesity is caused by bad genes AND bad lifestyle.

When Should We Intervene?

You probably already know that any extra fat cells we develop in childhood never go away. They are always with us, looking for those extra calories they can store as fat.

This study suggests that by the time we are in kindergarten, the die may already be cast. Those extra fat cells may have already developed.

And, for many people, the time to intervene may be even sooner. This study also showed that birth weight plays an important role as well. Children who weighed 9 pounds or more at birth were 2-fold more likely to be obese in kindergarten than children who weighed less than 9 pounds at birth.

Once again, a small percentage of overweight babies is due to genetics, but it is lifestyle choices during pregnancy that lead to the majority of overweight babies.

The authors of the study noted that most public health initiatives (school lunch programs, lifestyle education programs, etc.) are targeted at school aged children. The authors went on to say that by then it may be too late to have any significant effect on the incidence of obesity in our children.

They suggested that we need to place a stronger emphasis on influencing lifestyle changes that affect the weight of babies at birth and are likely to influence whether or not they become obese by the time they reach kindergarten.

That’s not the realm of public health policy. That’s our responsibility.

What Should We Do?

If You Are Pregnant:

The old adage “You are eating for two” was never true.

Aim for an extra 150 calories during the 1^st trimester, 300 during the 2^nd and 3^rd trimesters (That’s 1 or 2 servings of healthy foods).

Aim for little or no weight gain during the 1^st trimester and a total of 20-26 pounds during the last two trimesters (a bit less if you are overweight).

If You Have a Young Child Who Is Overweight:

Don’t restrict calories. Restricting calories can stunt growth and interfere with normal mental and physical development.

Encourage your kids to exercise rather than watching TV and playing video games. You may need to set the example, and that’s a good thing for you as well as for them.

Provide your kids with a healthy diet. For most kids, that means more fruits and vegetables and less sugary beverages, fruit juices, and processed snack foods. That may simply mean that you don’t bring those kinds of foods into your house. Again, that would probably be a good thing for everyone in the family.

I know some of you are saying “My kids won’t eat healthy stuff”. Let me give you my take on that.

When I was a kid, my mom had a pretty simple policy. If I didn’t like what she cooked, I didn’t have to eat it. I could simply wait until the next meal – when she would be serving the same kinds of healthy foods again.

I got the message pretty quick. It wasn’t eat healthy or eat junk food. It was eat healthy or go hungry. I decided early on that healthy was better than hungry.

Now, let me step down from my soapbox and summarize.

The Bottom Line:

1) The latest research suggests that if a child is overweight by kindergarten, they are likely to be overweight for the rest of their lives. So if you want to spare your kids and grandkids from a lifetime of obesity, you want to intervene early.

2) A small percentage of those kids are destined to be obese no matter what they do. However, for the vast majority of them obesity can be prevented by a healthy lifestyle.

3) If you are pregnant, don’t “eat for two”. That is terrible advice. If your pre-pregnancy weight is stable (neither increasing or decreasing), you only need to add a serving or two of healthy foods to your diet during pregnancy. Check with your doctor about the amount of weight gain that is right for you and follow their advice.

4) If you have a young child who appears to be overweight, don’t restrict their calories. Instead, provide them with healthy food choices and encourage them to exercise.

5) Finally, if you have been overweight since childhood, don’t despair. For most of us obesity is a combination of genetic predisposition and lifestyle choices. You can’t your genes, but you can change your lifestyle.

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.