Why hunger affects your health... and that of your descendants

It is well known that the proper functioning of our body depends on two types of factors: internal and external, or, in other words, genetics and environment. Most diseases are influenced, in varying percentages, by both components. Even the way we age depends as much on what we inherit as on what we do.

We list them as if they were two different things (nature vs. nurture, as the Anglo-Saxons say) when, in fact, they are more interrelated than it seems. And the main link that unites them is epigenetic changes, a series of reversible but long-lasting chemical modifications that are added to the DNA (epi- means precisely on) and alter the information it contains.

Many environmental factors have an impact on epigenetics, just as they also affect normal processes of the body's functioning, beyond the genes we are born with. Thus, these marks contain a lot of information, because they are like a trace that leaves the passage of time in our cells, like a clock or a diary. For example, we have recently seen how they have been used to measure theBiological age of Maria Branyas, who was the oldest woman in the world, and also for design an algorithm that can predict the progression of cancer, to cite two pioneering investigations led by Catalan scientists.

Thus, epigenetic changes would be a bit like the wrinkles and scars that appear on our faces over the years: a response to external (and some internal) factors that tell a story through a series of alterations in the base material. That's why it was surprising that, in the 1990s, it was discovered that these wrinkles, which were initially seen as something personal and non-transferable, could be passed on in some way to descendants.

Inheriting the 'wrinkles'

The first experiments confirming this unexpected phenomenon were conducted on laboratory animals, primarily in studies related to diet. It was found that if mice followed a high-fat diet, not only did they experience health problems, but their offspring were born with metabolic disorders. This suggests that we are what we eat, as the popular saying goes, but we should also add that we are what our parents ate.

Indeed, the impact of diet on the health of one generation and the next, through acquired and then inherited epigenetic markers, has also been seen in humans. Major tragedies, such as World War II or China's Great Leap Forward—during which up to 50 million people died of hunger—have also affected subsequent generations, starting with those still in their mothers' wombs: they have been shown to have a higher risk of developing mental disorders, such as schizophrenia. Thanks to the epigenetic changes acquired during this stress, the impact goes further: children of those born during a period of famine also suffer more infections, such as tuberculosis, and obesity and diabetes.

Current situations of extreme hunger

These figures are particularly worrying when we consider the places on the planet where extreme hunger has currently been officially declared. Gaza is what people talk about the most, but other territories at war, like Sudan or Mali, or politically unstable countries like Haiti, are experiencing similarly serious problems, which will affect not only those who suffer and survive, but also their descendants. A dozen countries are at risk of ending up the same way. Another reason—if more were needed—to fight armed conflict and ensure a minimum level of protection and well-being for all pregnant women and children around the world. Not only their health is at stake, but that of all those who come after them.

Epigenetics has experienced a boom in recent decades, as we have come to realize how important it is for understanding the details of many biological processes. At the beginning of the century, only a few hundred articles on the subject appeared each year in specialized journals, while in the last five years, the number has increased to around 15,000 annually. However, we still have much to learn about how the environment alters our genome without actually changing its essence.

However, the knowledge we have already accumulated allows us to draw a couple of important conclusions. First, what happens to us has an impact on our health, but also on that of our lineage, because some epigenetic changes are passed on, which should push us to be more responsible with the habits and living conditions of all human beings. And second, as we noted at the beginning, these chemical modifications are not permanent, which means that, with the right drugs, they should be able to be changed. The potential here to prevent and cure disease (and erase the negative inheritance from our parents) is immense.