Will Genetic Tests Help You Choose a Diet and Sport
Genetic tests help assess the risk of diseases such as type 2 diabetes. But are they able to determine the optimal diet for a particular person? Alexander Reznik, geneticist at Medsi on Solyanka, explains
The first thing a person who decides to undergo genetic testing faces is the variety of offers from different companies. They can be divided into two large groups: diagnostic and screening.
1. Diagnostic tests are prescribed by a doctor when it is necessary to establish an accurate diagnosis. Usually, such a study is required if the external manifestations of the disease do not fit into the textbook clinical picture of a particular hereditary syndrome. In this case, only a molecular genetic test makes it possible to make a diagnosis, and the patient’s parents can take a more balanced approach to the issue of planning the next children, determine the likelihood of having a second child with the disease, and, if necessary, turn to assisted reproductive technologies.
Some of these tests are carried out during pregnancy if, when reviewing the results of prenatal screening, the doctor suspects a chromosomal abnormality in the fetus, such as Down syndrome, Edwards syndrome, or Patau syndrome. But to find out before pregnancy about the likelihood of having a child with such a pathology using genetic testing, unfortunately, will not work.
2. A person can undergo screening genetic studies on their own, without the participation of a doctor. They are what they think of when they hear the phrase “genetic tests”. It is believed that they help to assess the risks of developing diseases before their first symptoms appear, and in the context of pregnancy planning, to check whether a dangerous hereditary mutation will be passed on to the child. In fact, such tests help to highlight more issues.
If we divide them into categories, we can distinguish:
- research in problems in the reproductive sphere. They help to find out from the standpoint of genetics why a couple fails to have children;
- oncological studies that are conducted to assess the risk of hereditary forms of cancer or select targeted therapy for an already diagnosed diagnosis;
- tests for healthy people aimed at assessing the risks of developing complex diseases. These are, for example, arterial hypertension, obesity, type 2 diabetes. The probability of their occurrence can be estimated with a high degree of confidence on the basis of the so-called polygenic calculation, when the analysis of the contribution of genetic changes to the risk of developing a disease takes into account the role of not just one gene, but tens, hundreds and even thousands of changes, at first glance randomly scattered over all human DNA.
Choosing a test: what is important to know
If you want to do a genetic test just to find out more about your health, and you have no medical indications for them, it is still worth consulting with a geneticist. The fact is that the studies of different companies differ from each other in the methods and data that are used to calculate the results, as well as the number of diseases assessed. It usually ranges from ten to 50. Without a specialist, choosing the right test and correctly assessing the risks to your health can be difficult. When choosing a genetic test in the context of pregnancy planning, oncology, and to solve a clinical problem, consultation with a geneticist is required.
If for some reason you do not want to see a doctor, here are the factors that must be taken into account when choosing a genetic test.
- Note their limitations: genetic tests, which can be done at will, do not detect all the dangerous mutations associated with hereditary diseases. They only determine a given set of hereditary mutations and help assess predisposition to several dozen age-related diseases.
- Regardless of the content of genetic testing, it is important that the research on which its results and related recommendations are based is conducted in humans and not in animals. It is desirable that these be the results of large-scale population genetic studies. They must have at least 1 thousand participants.
- Make sure that the company provides, upon request, comprehensive information about the scientific basis on which the study is based and what determines the choice of methods as the basis for testing.
If all criteria are met, the results of genetic testing can be trusted.
Will the test tell you about the right diet and sport?
It is impossible to choose the format of training or unambiguously say how exactly a person should eat, according to the test results. This is due to the fact that there are no large studies on the contribution of genetic characteristics to the composition of the diet and predisposition to a particular sport. Accordingly, there is no evidence base for such types of testing either.
Nevertheless, you can still find out about some features. For example, tests will allow:
- assess the tendency to increased or decreased levels of vitamins and minerals in the body in order to individualize the intake of dietary supplements;
- confirm or exclude the presence of intolerance to gluten, lactose, alcohol;
- assess the rate of metabolism of caffeine. If it is very low, then caffeine lingers in the body for a long time, which causes dizziness and headaches, an accelerated heartbeat and high blood pressure;
- determine the genetic characteristics of taste perception. For example, some people have a high sensitivity to bitterness, which causes them to avoid eggplant, radishes, arugula, and other bitter foods. If they are aware of this, it will be easier for them to balance or diversify their diet;
- understand the characteristics of drug metabolism, that is, the individual response of the body to a particular drug effect. At the same time, 30 drugs are evaluated in some tests, 100 in others. Accordingly, if there is a specific request for a certain drug, then it is necessary, together with a geneticist, to select a test that includes this drug;
- determine the predisposition to exercise, the features of amino acid metabolism and sports metabolism. This information will help you choose the right or correct training plan.