Why is Overeating While Breastfeeding a Negative Risk?

A new study done with mice suggests mothers who overeat while breastfeeding may have children who have a higher risk of becoming obese and going through puberty early.

Early puberty can be a perilous situation. It may lead to experiencing diabetes or reproductive issues later on in life.

The research from the study was presented at ENDO 2018, the Endocrine Society’s 100th annual meeting that took place in Chicago.

Lead researcher Mengjie Wang, a graduate research assistant at the University of Toledo College of Medicine and Life Sciences in Toledo, Ohio, said, “Formula feeding is well known to increase the risk of obesity in children. Our findings suggest, however, that when breastfeeding mothers do not eat a moderate and healthy diet, there can also be increased risks of various health problems in the offspring, including obesity, diabetes, advanced puberty and reduced fertility.”

She reiterated that this idea must be studied in humans to know whether it applies to our species.

Wang also noted that rates of early puberty are increasing all over the world. “Childhood obesity, a common health issue, is one of the risk factors for early puberty,” she said. “Previous evidence from animals has revealed that post-weaning overeating advances the timing of puberty, but we lack knowledge of how nutrition before weaning influences metabolism and reproduction.”

To test how obesity affects the timing of puberty, Wang gave one group of mice a high-fat diet starting from the date they gave birth and began breastfeeding their young until they weaned their pups.

She gave a second group of mother mice a regular, healthy diet for the same amount of time.

Wang found that overfeeding the mice during the breastfeeding period can cause obesity in the pups, which significantly alters the start time of their puberty. She concluded, “These results show that the breastfeeding phase is a critical window that influences when puberty happens.”

Later on when they reached adulthood, the pups underwent fertility tests. It was found that females had decreased litter size and both sexes had impaired pregnancy rates and increased risk of developing diabetes.

These results reinforced Wang’s conclusions that childhood obesity causes advanced puberty and metabolic disorders in adulthood. She said, “Correct treatment and follow-up are both important for patients with early puberty. Patients with early puberty should be aware that other health problems may arise after they become adults.”