There is no doubt that Environmental Factors has a strong involvement in the state of health and in the development of some diseases. Among these environmental factors, the biochemical composition of what we eat plays a key role.
On the other hand, it is known that the wide variety of food responses that can be observed from one individual to another are largely due to information encoded in DNA whose expression is being modulated by interaction with the environment, including diet and lifestyle.
Nutritional genomics is a discipline that studies this relationship between genetic information, diet and health. It does this through two main branches, nutrigenetics and nutrigenomics.
Nutrigenetics is the branch responsible for studying the relationship between genetic polymorphism and different individual responses to food. In other words, it studies how molecular variations of the same gene among different individuals generate different responses to the bioactive components of the diet and their consequences in the body.
The other branch, nutrigenomics, studies in the same way, but in the opposite direction. Nutrigenomics studies diet as an environmental factor that influences the expression of the genotype and, therefore, the phenotype of the individual. Specifically, it studies how the molecular composition of the diet can modulate gene expression, which affects protein synthesis (studied by proteomics), is for metabolism (studied by metabolomics) and, consequently, physiological state and health.
For example, nutrigenetics studies how the polymorphism of the gene encoding the enzyme methylenetetrahydrofolate reductase affects folate metabolism and its relationship with some diseases, such as venous thromboembolic disease3. In turn, nutrigenomics studies how diet affects the expression of this gene, which could be used to establish dietary guidelines as a preventive measure for venous thromboembolic disease in individuals with a genetic predisposition.
As nutrigenomics needs to know the pathophysiological response generated by the modulation of gene expression, some authors use nutrigenomics and nutritional genomics indifferently and consider nutrigenetics as a branch of nutrigenomics.
General foundations of nutrigenomics
Nutritional genomics began in the early 2000s after the sequencing of much of the human genome (complete sequencing was completed in 2005). Thanks to this sequencing, the molecular basis of predisposition to certain diseases, such as cardiovascular disease, obesity, cancer or diabetes, was discovered.
But having a genetic predisposition does not imply that the disease will develop. Gene expression is strongly modulated by the interaction of the environment, that is, by factors that come from abroad, such as diet, lifestyle and environmental factors.
In nutrigenomics, nutrients can be understood as molecular signals from the environment that are incorporated into the body through the diet and reach the cell. The cell can respond to these signals by modulating gene expression depending on the signals it receives and in what amount. As a result, different diets generate different patterns of protein synthesis and different metabolic patterns, which are closely related to health status.
Application in prevention and health promotion
With the information provided by nutrigenomics, it is possible to establish personalized diets according to the individual’s genotype and specific needs. This type of nutritional intervention can be a much more effective preventive and health promotion measure than the one based on epidemiological statistics observed in the general population.
Understand how diet influences metabolic pathways and homeostatic control at the cellular level It can be a great tool in the prevention and improvement of chronic diseases, especially those closely related to diet, such as obesity and type II diabetes, but also other diseases in which gene expression is involved, even when not strictly related to diet.
An important point of nutrigenomics is the identification of the marker of genetic predisposition that can be detected in the early stages of the disease, even before signs develop. At this stage, nutritional intervention would be more effective.
With the development of nutrigenomics it will also be possible to demonstrate the effectiveness of bioactive foods on health at a deeper level, which could lead to the development of better functional foods that can help maintain health based on individual needs.
One of the best-studied fields of nutrigenomics is obesity and its relationship to the FTO gene (Fat mass and obesity-associated protein, also known as alpha-ketoglutarate-dependent dioxygenase). In different studies, it was observed that patients with the AA genotype develop higher Body Mass Index (BMI) with high-fat or low-carbohydrate diets compared to patients with the TT genotype.
Another obesity-related gene is the APO B (Apolipoprotein B) gene. It has been observed that individuals with the GG genotype and high dietary fat intake (greater than 35% of caloric intake) develop a higher BMI than individuals with the AA genotype. This relationship was not found in diets with fat below 35% of caloric intake.
Therefore, by knowing the genotype of the obese patient, personalized dietary recommendations can be made to treat and prevent obesity. much more effective than diets based on observational epidemiological data in the general population.