Cienciaes.com: Environmental obesity | Science Podcasts

2010-11-28 11:24:23

Since 1993, scientists have known of the existence in the environment of substances called endocrine disruptors.

Sometimes the obvious, although true, is not the whole truth. The non-contagious obesity epidemic that the developed world is suffering is obvious; in particular our country, which in this case has not missed the train, despite the fact that obesity does not make it easy to get on it. Excess weight is closely linked to serious health problems, including cardiovascular disease, type 2 diabetes, hypertension and some types of cancer. Preventing obesity with a healthy diet and moderate exercise is the best way to prevent such problems, because it is equally obvious that those who gain weight do so because they eat too much for the exercise they do.

However, it is not clear why the obesity epidemic is happening precisely now. It is true that currently first world countries have an excess of very high-calorie foods. But there is also no doubt that throughout recent history, even when people did not exercise as much as they do now, there have always been people who have had an overabundance of food and have not become obese as a result. Excess food and lack of exercise alone do not explain the high prevalence of obesity that we suffer today.

For these reasons, it has been studied whether, in addition to the obvious reasons for obesity, there are others that are not so obvious. It is known that correct appetite control depends on hormonal factors. If these factors do not work well, eating disorders occur, including excessive food intake that causes obesity. Some researchers suspected that polluting substances could affect the correct hormonal balance that controls appetite. Were your suspicions true?
Unfortunately yes.

Endocrine disruptors

Since 1993, scientists have known of the existence in the environment of substances called “endocrine switches,” which interfere with the normal functioning of some hormones, enhancing or decreasing their physiological action. In general, endocrine disruptors are contaminants derived from insecticides and pesticides, or from industrial pollution, which is why they are more abundant in the environment today than just a few decades ago.

Depending on our genetic background, some of these substances will have different effects. For this reason, not everyone becomes obese, not even in a polluted environment and in a social environment in which abundant and appetizing foods are usually present at celebrations, meetings, etc. However, for some people, endocrine disruptors can condition the physiology of appetite from very early in their lives, and leave their mark until death, which will happen sooner than expected thanks to their action.

Pollution and childhood obesity

The early action of some substances on the hormonal control of appetite has recently been corroborated in studies carried out by Spanish researchers from the Environmental Epidemiology Research Center in Barcelona. The researchers studied 500 women from the first trimester of their pregnancy. They took their blood and analyzed it for the presence of several chlorinated contaminants that are very persistent in the environment. In particular, DDE, a derivative of the insecticide DDT, which is still used in some countries to combat the malaria-transmitting mosquito. The content of these substances in the mothers’ blood was then evaluated according to their possible effect on the growth and development of their children, once born.

Well, the results are worrying. Babies born at normal weight to mothers with high blood levels of DDE grew more rapidly during the first 6 months of life than babies born to mothers with low levels. As a result, at the young age of just 14 months, babies born to mothers with high blood levels of this substance were overweight four times more often than babies born to mothers with low levels.

These studies point to attacks on the environment as causes, or at least contributors, to the highest rate of obesity today. The environment defends itself against us and returns to us, in part, the damage we do to it. It is therefore advisable to always act in a respectful manner with the environment for our own benefit and that of our children.