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How To Eat For Your Genes, From An Integrative Gastroenterologist

Marvin Singh, M.D.
February 19, 2021
Marvin Singh, M.D.
Integrative Gastroenterologist
By Marvin Singh, M.D.
Integrative Gastroenterologist
Marvin Singh, M.D. is an integrative gastroenterologist in San Diego, California. He is trained and board certified in internal medicine and gastroenterology/hepatology.
Image by Jeanine Donofrio
February 19, 2021

It feels like every day someone is telling us to eat this or to eat that, but how do you know if this or that is actually good for you? This can be a tough question to answer without the proper understanding of what your individual body needs. That's where precision medicine—what I consider the future of health care—comes into play.

We now have tools at our disposal, which can help us understand how each person should eat in order to optimize their own nutrition. In other words, it is possible to eat for your genes.

How do I know what genes I have?

Nutritional genetics tests are available through a variety of companies and can often cost under $300. Ask your primary care physician or gastroenterologist if they offer nutritional genetics testing, and check to see if it's covered by your insurance. While most insurance companies may not reimburse the test, if the cost is manageable for you, the information you will glean is well worth the price. The key is to make sure you get the test from a reliable company, focused on high-quality, evidence-based recommendations.

While several companies conduct the same test, the recommendations in the reports can vary. Why is that? Well, while your genes are your genes—they aren't changing or shifting from report to report—the ways in which certain companies interpret the science and choose to educate you on it can differ. So, especially in this case, it is important to look at who is powering the interpretation of the results. 

5 common genes and what they do.

So, what exactly could you find out on a nutritional genetics panel? Some of my favorite genes are outlined below, but they are by no means inclusive of all reported genes.


This is a gene that you may have heard of. It produces an enzyme called methylenetetrahydrofolate reductase1, an important enzyme for folate usage in the body. Variations in this gene can help determine how individuals use dietary folate.

If you have a genetic mutation here, you may need to eat foods high in folate or take a supplement to offset any lower levels. Folate-rich foods include cruciferous veggies, like broccoli, kale, Brussels sprouts, and cabbage, as well as beets and beef liver.


This gene is part of the complex that helps regulate the expression of the LCT gene, which encodes for the enzyme lactase. Lactase plays a key role in breaking down lactose. This gene can help determine whether your bloat and GI distress are coming from milk and can help explain why you have trouble tolerating dairy (aka lactose intolerance2).

HLA Genes

This group of genes make proteins called the human leukocyte antigen (HLA) complex. They are responsible for differentiating the body's own proteins from foreign and possibly harmful proteins, via the immune system.


This is the gene for adenosine A2A receptor. It encodes for one of the main adenosine receptors, which has many functions in the body, including promoting sleep and calmness. Caffeine blocks adenosine receptors, which can cause stimulating effects. Those who have a mutation in this gene may be more likely to experience feelings of anxiety after caffeine intake4.

Together with the CYP1A2 gene (which is responsible for breaking down caffeine in the body), ADORA2A helps me guide patients in understanding how much, if any, caffeine they should drink regularly to reduce the risk of high blood pressure, heart attack, and anxiety.


This is an important gene because it directs the body to produce the angiotensin-converting enzyme (ACE), which plays a role in regulating blood pressure in the face of sodium intake5. Essentially, if you have a mutation in this gene, you are at greater risk of experiencing high blood pressure when you consume higher amounts of sodium.

By knowing about this mutation ahead of time, you are able to make the proper interventions in your diet and potentially bypass a major risk factor for high blood pressure and heart disease.

Bottom line.

There are so many amazing genes we can discover in simple nutritional genetics panels. The information you obtain from these tests can not only help you understand what your body needs and wants but also help you understand what your risks are for certain diseases, conditions, and nutritional deficiencies.

One of my regular (albeit, corny) sayings is if you don't know, then you don't know. If you don't know what your risk factors are for certain conditions, you are unaware of what to do in order to prevent or reduce the risk of developing those problems.

It is easier and better for you to intervene early rather than waiting until you have a problem. While we always want to work toward optimizing our health, there is some comfort in knowing you have a genetic issue that you can work around by eating in a way that is best for you.

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Marvin Singh, M.D. author page.
Marvin Singh, M.D.
Integrative Gastroenterologist

Marvin Singh, M.D is an Integrative Gastroenterologist in San Diego, California, and a Member of the Board and Diplomate of the American Board of Integrative Medicine. He is also trained and board certified in Internal Medicine and Gastroenterology/Hepatology. A graduate of Virginia Commonwealth University School of Medicine, Singh completed his residency training in Internal Medicine at the University of Michigan Health System followed by fellowship training in Gastroenterology at Scripps Clinic Torrey Pines. Singh was trained by Andrew Weil, M.D., a pioneer in the field of integrative medicine, at the Andrew Weil Center for Integrative Medicine.

Singh is currently the Director of Integrative Gastroenterology at the Susan Samueli Integrative Health Institute at UC Irvine. He is also currently a voluntary Assistant Clinical Professor at UCSD in the Department of Family Medicine and Public Health; prior to this, he has been a Clinical Assistant Professor at UCLA and an Assistant Professor of Medicine at Johns Hopkins University. Singh is a member of the American Academy of Anti-Aging Medicine, American College of Lifestyle Medicine, and many other societies. He is actively involved in the American Gastroenterological Association. He is one of the editors of the textbook of Integrative Gastroenterology, 2nd edition (a Weil Series text) and has written several book chapters and articles.

He is dedicated to guiding his clients toward optimal wellness every step of the way, using the most cutting edge technologies to design highly personalized precision based protocols. Towards this end, he founded Precisione Clinic and wrote the book Rescue Your Health to bring the best in preventive medicine to his clients.