How Your Genetics Impact Your Diet
When it comes to what we eat, most of us are on the hunt for the perfect diet. The diet that will help us get thin or stay thin. The diet that will give us a ton of energy. The diet that fixes all our digestive issues and cures our autoimmune disease. So we hunt for this perfect diet, trying out dietary theory after dietary theory, bouncing from fad diet to fad diet.
Maybe you find a diet that works well. Or maybe it only works well for a time. Or maybe you keep restricting your diet until one day all you’re eating is kale and lamb. And that is no way to live.
This approach to diet is haphazard and ineffective. It is like trying to find the perfect pair of jeans when they are all one size fits all. Maybe you will get lucky and find a pair that works, but the odds are slim to none.
We need to change our approach to our diet. Instead of trying to make yourself fit the diet, you need to make the diet fit you. You are unique, from your biochemistry to your genetics to your gut bacteria to your immune function. Your diet needs to reflect your individuality. When we think about diet this way, we realize that the “perfect” diet will be different for each person.
An important factor to consider when figuring out your diet is your genetics. We all have variations in our genetic code that result in different functionality of the enzymes and proteins in our cells. Some of these enzymes and proteins may be involved in how we process our food. So depending on our genetics, we may digest, absorb, metabolize and utilize components of our food differently compared to another person. This may mean that we can’t eat certain foods because they negatively impact our health but another person can. Or this may mean that we have a harder time utilizing certain nutrients from our food, so we need more of that nutrient compared to another person. Here are some examples of how your genetics impact your diet.
A variation in the TCF7L2 protein (a protein involved in turning on the expression of certain genes) influences how your body responds to certain grains and carbohydrates. If you have one variation of the gene, you have a 67% increased risk of developing type 2 diabetes when eating whole grains with a high glycemic load compared to the people with a different variation of the gene. To compensate for this genetic risk, people need to eat whole grains with high fiber content and avoid processed and refined grains.
Omega-3 Fatty Acids
Omega-3 fatty acids are important to our cardiovascular health. One way in which they prevent heart disease is by lowering triglycerides in the blood. But not everyone responds the same way to omega-3 fatty acids. For some people, increasing omega-3 fatty acids did not lower triglycerides in the blood, but for others it did. It turns out that how your body responds to omega-3 fatty acids is related to your gene for an enzyme called nitric oxide synthase. If you have one variant of the gene, the level of omega-3 fatty acids in your blood does not affect your triglyceride levels. But if you have a different variant, the level of omega-3 fatty acids impacts your triglyceride levels by up to 25%.
For many years, saturated fat has been vilified as the cause of all cardiovascular disease. The nutrition world is starting to change its tune a bit by claiming saturated fat is not bad and possibly even good. But before we make broad statements about saturated fat, we need to look at our genetics. The APOA2 gene codes for a protein that helps processes fats in our body. Depending on what variant of the gene you have, you may be more sensitive to saturated fats. Studies have found that eating a more than 22 grams of saturated fat a day with one variation of the gene increases your risk of obesity by 67%. But if you have a different variation of the gene, your saturated fat consumption does not affect your obesity risk.
Many of us have been told that sodium is bad and can increase blood pressure. But this isn’t necessarily true. It depends on our genetics. Specifically, it depends on your gene for your angiotensin converting enzyme (ACE). It turns out that with one variation of the gene, your sodium intake does not affect your blood pressure. But if you have another variation of the gene, your sodium intake can drastically affect your blood pressure.
Many of us feel like we can’t survive without our coffee. And when someone questions how much coffee we drink, we are quick to point out all the studies that say coffee is good for you. But those studies did not look at your genetics. And in fact, you may not be able to survive with your coffee. If you have certain variations in the gene for caffeine metabolism (CYP1A2), your coffee consumption may increase your risk of a heart attack. With this variant, drinking 2-3 cups of coffee a day increased your risk of a heart attack by 26% and drinking 4 or more cups a day increased your risk by 53%. Drinking 1 or fewer cups a day, however, did not increase the risk of a heart attack.
Hopefully, you’re beginning to understand that a cookie cutter approach to your diet is not the best way to find a diet that works for your health. We need to take into consideration our genetics, our gut bacteria, and our immune system when developing a customized diet. Unfortunately, the field of individualized nutrition is still under construction. We know these factors are important when it comes to diet and health but we don't understand how it all works yet. But while us doctors and scientists figure this out, there is still a lot you can be doing to improve your diet and health.
- Cornelis MC et al. TCF7L2, dietary carbohydrate, and risk of type 2 diabetes in US women. American Journal of Clinical Nutrition. 2009;89:1256-1262.
- Ferguson J et al. NOS3 gene polymorphisms are associated with risk markers of cardiovascular disease, and interact with omega-3 polyunsaturated fatty acids. Atherosclerosis. 2010;211:539-544.
- Corella D et al. APOA2, dietary fat, and body mass index: replication of a gene- diet interaction in 3 independent populations. Archives of Internal Medicine. 2009;169(20):1897-906.
- Poch E et al. Molecular basis of salt sensitivity in human hypertension: Evaluation of renin-angiotensin-aldosterone system gene polymorphisms. Hypertension. 2001;38:1204-1209.
- Cornelis et al. Coffee, CYP1A2 genotype, and risk of myocardial infarction. Journal of the American Medical Association. 2006;295:1135-41.
I'm Dr. Carly and my mission is to create a health revolution. I believe that another prescription is not the answer. I believe in using natural therapies that go beyond the symptoms. And I believe that doctors should spend way more than 7 minutes with a patient.