Excess calories during development of brain-altering reduce cravings for unhealthy food
Washington,US: In Molecular Metabolism, a Rutgers study found that early overnutrition rewires developing brains to seek unhealthy food in children whose mothers are overweight during pregnancy and nursing.
In an experiment that started by allowing some mice to become obese on an unlimited supply of high-fat food during pregnancy and breastfeeding while keeping other mice slim on an unlimited supply of healthy food, Rutgers researchers were able to demonstrate this link between mother and child in mice. When given access to unlimited good food, mice born to obese moms maintain their slimness as adults, but when provided access to poor food, they eat more than mice born to lean mothers.
The findings indicate that while people whose mothers were overweight during pregnancy and nursing may struggle to moderate their consumption of treats, they could safely eat their fill of healthy foods.
The study may also help inform the development of brain-altering drugs that reduce cravings for unhealthy food.
"People born to overweight or obese mothers tend to be heavier in adulthood than people born to leaner mothers, and experiments like this suggest that the explanation goes beyond environmental factors such as learning unhealthy eating habits in childhood," said Mark Rossi, a professor of psychiatry at Rutgers Robert Wood Johnson Medical School and senior author of the study.
"Overnutrition during pregnancy and nursing appears to rewire the brains of developing children and, possibly, future generations."
In the experiment, researchers gave the high-fat food to three sister mice and the healthy chow to another three of their sisters. Once breastfeeding was complete, the researchers turned their attention to the nearly 50 pups -- who predictably started at heavier or lighter weights, depending on their mom's diet.
Their weights converged (at healthy levels) after all the pups received several weeks of unlimited healthy chow, but they diverged again when the researchers offered them constant access to the high-fat diet. All the mice overate, but the offspring of overweight mothers overate significantly more than the others.
Further analysis indicated that the differing behaviors probably stemmed from differing connections between two parts of the brain -- the hypothalamus and the amygdala -- that arose because of differing maternal nutrition during pregnancy and breastfeeding.
The study has mixed implications for people born to overweight mothers who struggle with their own weight. On the one hand, it suggests the possibility of staying lean while eating healthy food to satiety and avoiding junk entirely. On the other hand, it suggests that efforts to eat moderate quantities of unhealthy treats may spur overconsumption and obesity.
Looking forward, the study's finding about disrupted brain circuits in the two groups of mice may help inform the creation of drugs that would block the excess desire to consume unhealthy foods.
"There's still more work to do because we don't yet fully understand how these changes are happening, even in mice," Rossi said. "But each experiment tells us a little more, and each little bit we learn about the processes that drive overeating may uncover a strategy for potential therapies."