What is Nutrigenomics
Biohackers and nutritionists increasingly recommend personalizing your diet to improve gut health, prevent disease, or lose weight. They suggest creating a menu based on your individual body characteristics. One way to do this is to turn to nutrigenomics.
Nutrigenomics is a science that studies how nutrition affects gene activity and body function. It is a young field: it was first discussed in the early 2000s. At that time, nutrigenomics emerged as a field that studies diseases associated with gene activity and how they are affected by compounds from food. For example, one nutrigenomics study showed that whole grains can help people with diabetes because they change the work of the APOA5 gene, which is responsible for sugar metabolism.
Nutrigenomics is now increasingly being talked about as a field that helps create a personalized diet. To do this, a person takes a sample of DNA – long molecular chains that contain the body’s “operating instructions” – and this sequence is decoded to learn about individual breakdowns in DNA links that affect health. For example, about the body’s ability or inability to digest different foods, as well as how quickly a person gains/loses weight.
This idea is actively monetized. There are many startups in the world that promise to develop a diet based on decoding your DNA, and even in Russia, there is an opportunity to take a test and receive, based on it, nutritional recommendations. But such a service costs a lot of money, so firs,t it is better to understand what genetic tests can help with and where they are powerless.
What a Genetic Test Can Tell You About Our Diet
Genes are sections of long DNA chains that are responsible for one “instruction” for the body’s work – for example, for assembling an enzyme that digests a particular compound. DNA (and genes) are present in almost every cell of the body. There are a lot of them, and they store information about the body as a whole: how we look, what diseases we have, and so on.
Genes not only store this information, but also pass it on to the next generation. Moreover, similar genes will be found not only in close relatives but also in entire nations. For example, due to common genes, almost all Chinese people have trouble digesting dairy products.
A genetic test will help “read” DNA and determine which products are suitable for a person and which ones are best avoided. Let’s figure out which nutritional and digestive characteristics are inherited and why we need to know about this in advance by taking a test.
Weight gain
There is no single “big bone” gene. But there are dozens of genetic variants—small changes in the gene sequence—that increase the risk of weight gain. For example, such variants in the FTO and МC4R genes determine the feeling of hunger and the rate of satiety.
People with these variants gain weight faster and may suffer from obesity. For them, classic diets with fasting days and other restrictions do more harm than good. The doctor may recommend frequent fractional meals or advise them to eat slowly in order to catch the feeling of satiety and not overeat.
Lactose
Dairy products contain a special carbohydrate called lactose. To digest it, the body needs a special enzyme called lactase. The activity of this enzyme can vary, and if it is low, lactose is not digested, and a person experiences unpleasant symptoms (diarrhea, bloating, nausea) after consuming dairy products.
Lactose intolerance has an evolutionary reason. The ability to digest milk protein appeared in northern peoples 10 thousand years ago, when they domesticated animals that produce milk. It helped to obtain energy in cold and dark conditions. Southern peoples had access to a variety of food and sun, so they did not need to digest milk. Lactose intolerance is also preserved in the descendants of southerners – for example, now about 90 percent of Chinese have it.
Information about lactase activity is also stored in genes, and with the help of a genetic test we can find out the degree of our milk tolerance.
Gluten
Gluten is a protein complex found in wheat grains and, accordingly, in products made from wheat. Gluten intolerance (also called celiac disease) sometimes develops in people with errors in the immune genes – HLA-DQ2 and HLA-DQ8 .
But if you have such genes, it does not mean that buns and pasta are contraindicated for you. The disease can remain in a “dormant” state for a long time. Celiac disease can be provoked by shocks: emotional stress, pregnancy or surgery. A genetic test will help identify a predisposition to the disease and adjust your diet and lifestyle.
Vitamins and microelements
For example, to form vitamin A, the body also needs a special enzyme. The instructions for its production are written in the BCMO1 gene. Small errors in this instruction lead to the enzyme not working well, and the body has less vitamin A. Then you need to include in your diet foods and supplements that contain the vitamin in ready-made form.
Genes can also affect zinc metabolism. Zinc is needed by pancreatic cells, so they have a special protein that “pumps” this metal into them. If there are errors in the gene for this protein, zinc does not enter the cells well, and this increases the risk of developing type 2 diabetes.
Caffeine
The body also has its own enzyme for processing caffeine. It is encoded by the CYP1A2 gene . Depending on it, a person can get a “fast” or “slow” version of the enzyme. And if in people who quickly process caffeine, it improves the health of the heart and blood vessels, then for those who were unlucky enough to be born with a slow version of the gene, coffee, on the contrary, increases the risk of a heart attack. A genetic test will help determine which version you have and tell you how much coffee you can drink without harming your health.
Where genetic testing fails
Genes do influence the metabolism of some foods and the risks of diseases associated with them. But digestion also depends on many other parameters: past illnesses, the composition of the intestinal microbiota, lifestyle, environment, stress, and so on.
There are a great many products and dishes, and tastes in food often appear not because of DNA sequence, but because of upbringing and culture. Surely each of us would prefer mom’s borscht to another dish with the same nutritional content.
Therefore, it is impossible to create an ideal diet based only on a genetic test – not only will it not be able to take into account all the characteristics of the body, but it may also simply turn out to be tasteless and not suitable for you.
This is the conclusion reached by a group of scientists from the Institutes of Nutrition in Great Britain, Ireland, the Netherlands and other countries. They conducted a study in which they compared different approaches to nutrition, and it turned out that personalized nutrition plans do provide better health indicators, but the scientists did not find a statistical difference between a simply well-designed diet taking into account anamnesis and an individual plan based on the results of a genetic test.
That is, simply creating a good, balanced diet with a nutritionist or dietitian is not only easier and cheaper than doing a genetic test, but also just as effective and useful.
And it is better to leave nutrigenomics for its original purpose – to find the causes of diseases and ways to treat them. To do this, contact a doctor – he will consider your case individually and prescribe a genetic test if there is a suspicion of hereditary diseases. In other cases, simpler and cheaper tests will be quite sufficient.