The biology of aging changes everything! A study in geriatrics reveals that our longevity depends 50% on a key factor. Here’s how to live 100 years.
Why do some people reach the age of 90 or 100 in great shape, while others see their health decline much earlier? We have always been told that the secret of centenarians lies in a balanced plate, composed for example of fish whose omega-3 preserves cognitive abilities, regular physical activity and plenty of sleep. But in reality, the biology of aging is more complex. If geriatrics has long focused on healthy living, a major meta-analysis has just broken this taboo: our habits are not everything. Another factor, linked to our biological heritage, would weigh much more heavily than expected in the mechanism of human longevity.
Originally, the researchers wanted “understanding human longevity and ways to improve it” by studying data from three groups of twin subjects, over more than a century of scientific analyses. They compared twins raised together to those raised separately, which allowed them to more precisely isolate the possible influence of genes from that of the family environment. “For many years, lifespan has been attributed primarily to non-genetic factors, fueling skepticism about the genetic determinants of longevity” remind the scientists. Indeed, until now, science estimated that genetics only accounted for 10 to 25% of a person’s life expectancy, and some studies suggested even lower figures.
The problem with old studies is that they did not clearly distinguish deaths linked to biological aging from those caused by external factors. This is what researchers call “extrinsic mortality” : these are deaths caused by external causes, such as accidents, violence or infections. Using new mathematical models and simulations to correct for this bias, they managed to isolate intrinsic mortality (linked to aging and associated diseases) and revealed in the journal Science that “the heritability of intrinsic human lifespan exceeds 50%”. In short, this means that the lifespan of an individual would depend 50% on the DNA transmitted from generation to generation. A figure much higher than what we thought until then.
This genetic influence changes the perspective for tomorrow’s medicine. As Ben Shenhar, one of the authors of the study, points out, “This encourages the search for genetic variants that extend lifespan, in order to understand the biology of aging and, potentially, develop treatments”. By identifying genes associated with people who reach old age in good health, science hopes to better understand the biological mechanisms capable of protecting humans against cellular decline. But there is no question of giving up under the pretext that “everything would be written” in our genes. They weigh more than expected in the balance but do not decide alone.
Although approximately 50% of our longevity is inherited, our destiny is not immutable. Our lifestyle – diet, physical activity, sleep, exposure to stress or pollution – does not directly alter our DNA, but influences the way in which it is expressed. This is what scientists call epigenetics. Clearly, certain genes linked to aging or diseases can be activated or slowed down depending on our lifestyle. Know that “Your genes are much more important than we thought” Above all, it allows you to anticipate your weaknesses in order to act on them before they are expressed. Because if we do not choose our genetic heritage, we keep control over the way it is expressed.
