September 19, 2020

Genes, diet and chronic diseases


Good eating habits are the best strategy to prevent chronic degenerative diseases and promote health in the population. However, despite the research of the last decades, the concept of “good eating habits” or “good nutrition” is difficult to define unequivocally for the entire population, everywhere and at all times of life. . Despite this, a good number of countries have released dietary guidelines to educate the population about the scientific consensus on a healthy diet. However, adherence to these recommendations and their success have been limited, as evidenced by the fact that the most common chronic diseases with a strong nutritional component (eg, obesity, diabetes) continue to increase.

Part of the problem is that each of us responds differently to the environment and especially to the diet. This variation between individuals has emerged through hundreds of thousands of years of evolution, which has led to maximizing the positive interaction between nutritional resources and population genetics. A classic example of this evolution is found in the ability of adult human beings in certain geographical locations to maintain the ability to consume milk in adulthood, due to a mutation that arose about 15 thousand years ago near the gene for lactase, the enzyme that metabolizes lactose, the most abundant carbohydrate in milk. As a result of this mutation, some subjects in populations whose livelihood came from livestock, could have access throughout their lives to a highly nutritious product that others could not assimilate, giving them a reproductive advantage and contributing to the prevalence of this mutation increasing. in these populations from generation to generation.

In other cases, the evolution was apparently paradoxical, since it favored the prevalence of certain diseases, such as those related to the functioning of hemoglobin, but which in the end ended up being protective of more lethal diseases such as malaria. In addition, in this case the protection was increased by components of the diet such as beans.

There is also talk of the presence of “sparing genes”, that is, those genetic variants that gave us the ability to more easily store the energy of the diet as fat and that was vital for the survival of our ancestors in times of famine. However, these sparing genes can be an important factor in the current obesity epidemic, since it favors the accumulation of adipose tissue or makes it difficult to lose it at a historical moment when storing energy for the future is no longer a priority in affluent societies.

Another important component to consider is adherence to the recommendations. If a subject does not find them attractive or according to their preferences, it is highly unlikely that they will be followed in the long term. Therefore it is also important to understand individual food preferences and adapt the recommendations to them.

The circadian system

It is important to emphasize, as we have already indicated, that genetic adaptations take thousands of years to exert their effect at the population level. However, living things also need to adapt to rapid changes in the environment. An obvious example is the circadian rhythm. Our organism has to respond in a rhythmic and coordinated way to the different activities that we carry out during the day, of which the most apparent are sleeping and eating. For this we need a rapid biological response system that is determined by the so-called clock genes, with a central clock in the brain, but with peripheral clocks in all our organs. The same goes for meals, and the variety of foods we consume at different times of the day and from one day to the next.

The ability to regulate our genes in a fast way is defined by epigenetic mechanisms, which take place without changes in the sequence of our genome, but in changes to some of its letters, equivalent to the changes we introduce when writing when we put accents or other spelling signs by means of which, and without modifying the letters or the words, we significantly change the meaning of the sentences. Unlike genetic mutations, these epigenetic variations induced, or in response to environmental changes, are rapid and reversible. A sample of its effect we have in the differences that are observed in identical twins (with identical genomes) over the years if they have been exposed to different environmental factors such as diet, tobacco, exposure to the sun, etc.

So for some time we have been investigating how genetics and epigenetics can help us personalize our diets and improve our health. But if this were not complex enough, recent years have revealed to us that we are not alone, and that throughout our lives trillions of bacteria accompany us, being an intrinsic part of our lives, and especially those that we carry in our intestines. Its composition is essential to define not only in terms of calories or compounds extracted from the food we eat, but also in the risk of common physiological diseases, such as obesity. But, in addition, every day there is more evidence of communication between intestinal bacteria and the brain that can influence our habits and behavior, as well as mental illnesses.

Prevent diseases

This leads us to the possibility that in the future, which we hope is close, we can, through a combination of measurements of the genome, the epigenome and the microbiome (the set of bacteria of our intestinal flora) and with the implementation of artificial intelligence , identify both the individual’s risk of suffering diseases, as well as the ability to prevent and even cure them, through the appropriate and scientifically sound use of personalized nutrition, also known as precision nutrition.

At the present time, we are merely scratching the surface of personalization, as most products on the market focus on either genetics or the gut microbiota without the depth and integration that are essential for responding. Complete and effective for those who are already looking for them in order to live longer and better.

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