Kids who exercise can undo damage of maternal obesity

It's possible the detrimental health effects maternal obesity has on children can be avoided – or at least minimized – if kids are active during adolescence, a new study reports.

Researchers from Johns Hopkins used an animal model to examine rats whose mothers were fed a high-fat diet during pregnancy and nursing. Some of the offspring were given free access to running wheels in their cages, while others had to remain sedentary.

Despite the fact that both the active and sedentary rats weighed the same, the rats who exercised had fewer fat deposits – and also showed heightened sensitivity to hormones that regulate appetite, even after they stopped running on their exercise wheels.

Hunger hormones

To examine how exercise influenced appetite, the researchers injected the rats' brains with the appetite-suppressing hormone leptin when they were 14 weeks old. Leptin is secreted naturally by fat cells, helping the body to regulate hunger and maintain a healthy weight. In obese people, however, leptin levels are usually higher in the bloodstream, causing individuals to develop an insensitivity to the hormone. Eventually their brains stop responding to it, said study leader Kellie L. K. Tamashiro.

After being injected with leptin, the rats who had exercised tended to eat less, while the sedentary rats didn't show any changes in appetite.

"There was something about the exercise that improved their leptin sensitivity, even the equivalent in humans of years later," Tamashiro said.

Implications

The study suggests that exercise might enable human brains to respond better to lepton – and therefore help people to eat less, the researchers said.

Previous studies by Tamashiro and her team have shown that rats born to mothers fed high-fat diets can avoid obesity and related health disorders if the offpsring get normal levels of dietary fat right after birth.

"Our research suggests that efforts to increase activity in kids could have positive long-term effects, regardless of whether they continue to exercise into adulthood," Tamashiro concluded.

Source: Johns Hopkins Medicine