Weight regain after a period of weight loss is a common reality for many people. The phenomenon, popularly called “accordion effect “, is often related to the difficulty of maintaining low-calorie diets in the long term. However, a new study shows that the cause for this may be related to epigenetics .
Researchers at the Federal Institute of Technology Zurich (ETH Zurich), Switzerland, discovered that the “accordion effect” may be related to changes in the DNA of fat cells in people with obesity. The discovery, published in the scientific journal Nature on Monday (18), can help in the development of new treatments that lead to lasting weight loss.
Epigenetics is an area of biology that studies changes in gene expression that do not involve changes in the DNA sequence. This means that external factors — such as diet, stress, lifestyle and pollution — can influence the activation or repression of genes in DNA. These epigenetic changes affect how DNA is read and interpreted by cells.
Research in epigenetics is important to understand how these environmental factors and a person’s lived experiences can cause epigenetic changes that affect the risk of diseases such as cancer, diabetes, psychiatric disorders and, in the current case, obesity.
What did the study find?
Researchers at ETH Zurich looked for the molecular causes of the accordion effect. To do this, they carried out the study in mice, analyzing fat cells in overweight animals and in those who lost excess weight through diet.
Research revealed that obesity led to characteristic epigenetic changes in the nucleus of fat cells. According to researchers, these changes remained even after a weight loss diet.
“Fat cells remember the overweight state and can return to that state more easily,” explains Ferdinand von Meyenn, Professor of Nutrition and Metabolic Epigenetics at ETH Zurich in statement.
Scientists were able to show that mice with these epigenetic markers regained weight more quickly when they were given access to a high-fat diet again. “This means we have found a molecular basis for the accordion effect,” says von Meyenn.
In other words, it is as if the DNA of the fat cells with this epigenetic marker have a “memory” . Even after the mice lose weight, this “memory” causes them to regain weight when they return to a high-fat diet or the usual diet they ate before starting a calorie-restricted diet for weight loss.
“Because of this memory effect, it is very important to avoid being overweight in the first place”, highlights Fernando Von Meyenn.
Same mechanism was found in humans, researchers say
Although the study was carried out in mice, the researchers found evidence of this same mechanism in humans. Scientists analyzed biopsies of adipose tissue from previously overweight people who had bariatric or gastric bypass surgery.
The tissue samples came from several studies carried out at the Karolinska Institutet in Stockholm and at hospitals in Leipzig, Dresden and Karlsruhe. In these samples, the researchers looked at gene expression rather than epigenetic markers. However, the results are consistent with those in mice.
On the other hand, researchers have not investigated how long fat cells maintain this “memory” of obesity.
“Fat cells are long-lived cells. On average, they live for ten years before our body replaces them with new cells”, says Laura Hinte, a doctoral student in the group of researchers.
Furthermore, it is not yet possible to alter these epigenetic changes in the cell nucleus with medications, “erasing the memory”. Researchers are hopeful that this will be possible in the future.
“It is precisely because of this memory effect that it is so important to avoid being overweight in the first place. Because this is the simplest way to combat the accordion phenomenon”, says von Meyenn.
The researchers also highlight that other cells may be involved in weight recovery, as they also have “epigenetic memories”. They say it is “quite conceivable” that cells in the brain, blood vessels or other organs also remember obesity and contribute to the accordion effect. The next step for scientists is to find out if this really happens.
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This content was originally published in “Efeito accordiona”: researchers discover what could be behind the CNN Brasil website.
Source: CNN Brasil
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