Food Code
How Products Change Our Genes
RIA Novosti, Vladislav Strekopytov
Scientists believe that substances contained in food can trigger molecular mechanisms that reprogram DNA. A new direction has even emerged in science — nutrigenomics, which studies the relationship of products with gene expression. Is it possible to influence the biochemical processes in the body with the help of a diet, reducing the risk of certain diseases, — in the RIA Novosti article.
Milk and alcohol
Biologists have long found out that the genome of any organism is able to adapt to the environment. Thanks to this, all living beings, including humans, are continuously evolving. Lifestyle, climate, contact with certain pathogens and other factors determine the emergence and consolidation of genetic variants that ensure adaptation and maximum survival. Not the last place in this row is occupied by the structure of nutrition.
A typical example: among the inhabitants of Northern Europe, fresh dairy products are absorbed by the body not only in infancy. Milk contains the disaccharide lactose, which requires a special enzyme — lactase to digest. The gene encoding it is usually active only in newborns. After weaning, its expression weakens, and the level of lactase decreases. However, the Dutch, Swedes, Norwegians, Danes and Britons produce lactase up to 20 years, and sometimes throughout life.
DNA analysis of the remains from archaeological excavations showed that 10-12 thousand years ago, corresponding mutations appeared in the genome of northern Europeans. According to scientists, this gave an advantage in the struggle for survival and allowed to settle territories that are not suitable for agriculture, but are quite suitable for breeding dairy cattle.
Percentage of adult population able to digest lactose
Another example is the genes encoding alcohol dehydrogenase (ADH). It is an enzyme responsible for the metabolism of ethanol in the liver and gastric mucosa. There is a centuries—old tradition of drinking alcohol in the Mediterranean, and southern Europeans are distinguished by increased expression of ADH genes compared to residents of Southeast Asia, where they drink mostly tea.
Geneticists have found that in Chinese, Japanese, Koreans and Vietnamese, one of the genes of the ADH cluster has been replaced with a polymorphic modification that promotes the rapid conversion of ethanol into acetaldehyde, which is significantly more toxic than alcohol.
The ALDH gene encoding aldehyde dehydrogenase, a liver enzyme that converts acetaldehyde into acetic acid, is also atypical for them. This variant of the enzyme is less effective than that of the Europeans.
Metabolic correction
Changes in the human genome under the influence of external factors are epigenetic, affecting the expression of individual genes, but not their overall sequence. Each gene in the DNA is responsible for a particular protein. The proteome, the totality of all proteins, determines a set of metabolites — molecular compounds on which the speed of biochemical reactions and metabolism in the body depend. Thus, genetic features directly determine metabolism.
Until recently, research in the field of nutrition was limited to studying the effects of food on health. In recent years, at the junction of genetics, dietetics and medicine, a new scientific direction has emerged — nutrigenomics. Its motto is a phrase attributed to Hippocrates: "Let food be your medicine, and medicine be food."
The practical application of this approach is a method of metabolic correction based on the identification of early markers of metabolic disorders. It is planned to use it to treat obesity, cancer, type 2 diabetes, heart and vascular diseases. All these pathologies are largely laid down at the genetic level, but are not associated with any particular gene.
Nutrigenomics considers metabolic processes as links of one chain — from DNA to metabolites. Genetic information sewn into DNA is transferred to RNA during transcription, which, in turn, serves as a matrix for the synthesis of protein enzymes. This is a feedback loop: the initiation of transcription depends on the availability of substances necessary for the formation of proteins.
Food is able to influence both the direct process — to trigger gene expression, and the reverse — to signal the presence of the necessary enzymes. In addition, certain nutrients can turn on or off genes encoding regulatory hormones. Violations in their products cause serious diseases.
Genetic Dietetics
Scientists have just begun to decipher the "messages" sent by individual products and acting as genetic switches. However, many diagnostic centers already offer nutrigenetic tests and the development of personal recommendations on healthy nutrition based on them. The first such test was registered in the US Food and Drug Administration (FDA) in 2017.
Analysis of the polymorphism of genes responsible for controlling the body mass index and indicating intolerance to certain foods allows us to identify a hereditary predisposition to deficiency of certain vitamins or elements. So far, the accuracy of the tests is very low and based on their results, it is impossible to form a comprehensive picture of the metabolism in the body.
In the future, scientists believe, a whole direction of personalized medicine will be formed — genetic dietetics. Nutritionists in cooperation with geneticists on the basis of genetic testing will be able to draw up individual nutrition protocols to preserve health and prevent diseases. We have already developed preliminary nutrigenetic recommendations for patients with hypertension, cancer, diabetes and cardiovascular diseases.
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