Saed News: Previous studies have shown that obesity in either the mother or father can cause metabolic changes in offspring and increase the risk of diseases; however, the exact mechanism of this transmission has not been clear until now.
According to SAEDNEWS, researchers have found that a father’s obesity is transmitted to the embryo through sperm and leads to metabolic dysfunction in offspring. The good news is that weight loss in the father can reverse these effects.
According to the scientific group of IRNA, MedicalXpress reported that previous studies have shown that obesity in either parent can cause metabolic changes in offspring and increase the risk of disease; however, the exact mechanism behind this transmission has remained unclear.
A new study from the University of Southern Denmark (SDU), published in the journal Nature Communications, has demonstrated the mechanism of this transmission through the father’s sperm to the embryo.
Researchers conducted experiments on mice. They observed that the offspring of obese males were born with normal weight but gradually developed impaired glucose uptake and insulin resistance (meaning body cells do not respond properly to insulin, leading to high blood sugar), which can lead to type 2 diabetes. This condition is referred to as silent metabolic dysfunction. Interestingly, male offspring were more affected than females.
Professor Jan-Wilhelm Kornfeld, head of the research group, said: “We also observed a tendency toward metabolic disorders in females, but it was not as severe as in males. Similar to humans, where women are metabolically more resilient.”
Researchers found that in mice made obese through a high-fat diet, a signaling molecule called “let-7” was excessively produced in their fat tissue. These molecules were also found in the sperm of obese animals and were transferred to the egg during fertilization.
In embryos, these excess molecules disrupted mitochondrial function (the cell’s energy-producing “powerhouses”), and this disturbance permanently altered how offspring store and use energy.
Researchers returned obese male mice to a normal diet. After about nine weeks, once their weight returned to normal, excess let-7 molecules disappeared from their fat tissue and sperm. When these mice reproduced, their offspring were born completely healthy.
To confirm these findings in humans, researchers studied 15 severely obese men (average body mass index close to 40) who were preparing for fertility treatment. Initial analyses showed elevated levels of let-7 in both fat tissue and sperm.
After six months of lifestyle intervention and dietary improvement, the levels of this signaling molecule significantly decreased.
Professor Marcelo Mori, a professor in the Department of Biochemistry and Tissue Biology at the State University of Campinas, said: “The results show that the greater the weight loss, the lower the level of let-7 in sperm.”
Professor Kornfeld said: “There is strong evidence that sperm partly reflects a man’s health. It seems that conceiving a child under conditions of stress, infection, poor nutrition, or any other health issue is not ideal. Children conceived under such imbalanced conditions are generally less healthy.”
