Diet and genetics influence each other

Diet and genetics influence each other

June 03, 2016

Diet and genetics influence each other

Food and genes are constantly talking to each other, and their dialogue has an impact on many aspects of health and society, so much so that it can even lead to the birth of new scientific disciplines.

The link between what we eat and what is written in our DNA - our genetic code - has assumed unprecedented importance in recent decades, partly due to advancements in research and techniques of molecular biology. This has led to the advent of new sciences such as nutrigenomics and nutraceuticals, which examine this link in depth with the aim of improving the health of individuals by means of a personalised diet based on genetic makeup.

When food “pushes” DNA
Practically all the foods we put on our tables contain molecules which can have a direct or indirect influence on the risk of developing illnesses by acting on our DNA. In other words, food influences our gene expression, and can modify it, sometimes dramatically, with significant consequences for our health, both positive and negative. The discipline which studies the relationship between diet and the modification of gene expression is called nutrigenomics, and it presents a new way of viewing nutrition: it is no longer just about calories and nutrients, but a tool to “push” genetic makeup in a specific direction. This does not mean modifying the sequence or the structure of DNA, but rather altering the functioning of a gene which, in turn, will modify its ability to produce proteins. And if one of these proteins is, for example, an enzyme involved in the mechanisms that regulate digestion, it will affect the ability to digest certain nutrients. But food does not only influence the genes involved in the digestive process and the absorption of nutrients: in many cases the targets are genes involved in inflammation, the immune system or cell growth and proliferation, a list which is growing longer and more complex by the day. In this way, scientists are working to understand the vital link between food and illnesses like cancer, Alzheimer’s and diabetes.

DNA determines the effect of food
But if it’s true that the food we eat influences our DNA, the reverse is equally true: the specific characteristics of each individual’s genetic makeup can result in different responses to the same nutrient. Therefore, a certain food may have a very different effect on one person than it has on another. It’s all the fault - or the merit - of DNA, and in particular of tiny differences known as SNPs (single nucleotide polymorphisms) present in the genes, which, albeit minute, can have a considerable impact on various processes concerned with the absorption and use of nutrients. In many cases these differences at DNA level have resulted in evolutionary advantage: if a certain variant allows the digestion of milk, for example, individuals that possess this variant and live in areas where milk is a staple will undoubtedly have an advantage over those which have a different variant. The ultimate aim of nutrigenetics (the branch of science which looks at how differences in DNA determine individual responses to foods) is a personalised diet which would take into account each person’s genetic makeup, rather than merely standard values such as weight, height, gender and age.

Foods become medicines
Let food be your medicine and medicine be your food. Hippocrates was saying it thousands of years ago and now neutraceuticals is saying it louder and clearer. This branch of science, whose name was coined in the late 1980s from a fusion of the terms nutrition and pharmaceutical, studies the curative potential of foods, based on the fundamental principle that all foods contain substances which act on the organism and on health, just like pharmaceuticals. Nutraceuticals experts study the molecules in animal- and plant-based foods, but also in micro-organisms and minerals, in order to understand how they act on health and ultimately to determine the dosage and methods in which they may be used to prevent or cure illnesses. In some cases this means creating specific supplements, in other cases it’s a matter of prioritising a particular nutrient or establishing a series of specific dietary recommendations.

Genetics and the Double Food Pyramid
In the light of these new sciences, does it still make sense to defend a diet such as the Mediterranean, or a food model like the Double Pyramid proposed by BCFN? The answer is yes, because molecular studies are in fact confirming (and making even more specific) what epidemiology has discovered: foods that have positive effects are the same foods that are good for you and for the environment. What we can look forward to from scientific progress is increasingly personalised profiles which can identify - within these beneficial foods - which ones are particularly appropriate for a specific individual or for the prevention (or treatment) of a disease. In order to achieve this ambitious outcome, research investment in this sector is increasing enormously. However, these are complex investigations which will not give results in the short term: the volume of data to be analysed is vast, and requires the availability of powerful digital tools and the sharing of results on an international level.

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