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An international team of researchers has discovered that the IRS1 gene, associated with a lower body fat increases, paradoxically, the risk of cardiovascular disease and type 2 diabetes. According to Dr. Belén Peral, a researcher at the Biomedical Research Institute Alberto Sols (CSIC-UAM) who participated in the study, “the finding is more evident in men than in women, because they accumulate less fat under the skin and more fat visceral. ”

Being a lean not always mean having a low risk of developing metabolic diseases such as type 2 diabetes or cardiovascular disease. This is shown by a study published in the journal Nature Genetics by a consortium of researchers from 72 scientific institutions from 10 countries, led by Dr. Ruth Loos of the Epidemiology Unit of the Medical Research Council, Cambridge, UK.

The work is based on genetic association studies to find possible correlations between 2.5 million genetic variants across the entire human genome and body fat percentage of more than 75,000 people (women and men from different countries).

In addition to confirming the involvement of a gene previously associated with obesity-called FTO (fat mass and obesity associated) – work successfully identified two new regions in the genome associated with the amount of body fat: a gene near SPRY2 (Sprouty homolog 2 , Drosophila) and another near the gene IRS1 (Insulin Receptor Substrate 1).

The variant discussed in greater detail by scientists in the study was related IRS1 gene, as this not only indicates a lower body fat but, in turn, predispose them to metabolic and cardiovascular diseases commonly associated with obesity.

For Dr. Belén Peral, a researcher at the Biomedical Research Institute Alberto Sols (CSIC-UAM), and author of the article in question, the study has revealed another surprising finding: “The association between IRS1 gene variant and reduced body fat occurs mainly in men, which means that men who carry in their DNA that are specific polymorphism at the same time thinner, Meratol more susceptible to metabolic diseases such as type 2 diabetes and cardiovascular disease. ”

Less fat on the surface but more fat on the inside

How do you explain that a variant in a gene associated with lower amounts of body fat may itself be harmful to the body? To answer this question, researchers investigated the distribution of body fat in people who carry the variant in the gene IRS1, and found that this gene variant only reduces fat under the skin (subcutaneous fat), but not the most harmful to the body, which is what surrounds the organs in the abdomen (visceral fat).

The authors argue the possibility that people with this gene variant are less able to store subcutaneous fat, and therefore must store fat in other parts of the body where it can interfere with normal organ function. This phenomenon would occur more frequently in men, as they accumulate more visceral fat in the abdomen, a situation that is more harmful to the body than the alternative “feminine” of increased subcutaneous adipose tissue, mainly in the gluteal-femoral.

Dr. Pearl explains why it is more harmful to the body increased visceral fat than the subcutaneous, “When the visceral adipose tissue size exceeds limits, fatty acids are released into the bloodstream and accumulate in the contribute to generating liver where insulin resistance, which favors type 2 diabetes, alterations in lipids and hypertension. These fatty acids also reach other parts of the body such as the pancreas, muscles and heart, which infiltrate fat. Moreover, visceral adipose tissue cells, called adipocytes produce pro-inflammatory substances that lead to the development of vascular problems. Ischemic heart disease is just one of many possible consequences. ”

The importance of genetic information

Our genetic makeup can help us determine if we are predisposed to certain diseases, but we must not forget that diet and physical activity also play a vital role in maintaining good health. “When we talk about obesity and other diseases resulting from overweight, know that it is multifactorial disorders in which genes play an important role, hence the importance of further study of this subject to open new therapeutic targets in the fight against this epidemic. But are not the only cause, lifestyle and diet, sedentary lifestyle, a good mental state and a host of environmental factors can help to counteract the effects or at least mitigate, “concludes Dr. Pearl.