In the United States, 64 percent of women of reproductive age are overweight and 35 percent are obese. New research at the Oregon National Primate Research Center (ONPRC) links an unhealthy diet during pregnancy to mental health disorders, such as anxiety and depression, in children.

The study, led by Dr. Elinor Sullivan, an assistant professor in the Division of Neuroscience at ONPRC at OHSU in Portland, Oregon, tested the effect of a maternal high-fat diet on nonhuman primates, tightly controlling their diet in a way that would be impossible in a human population. The study revealed behavioral changes in the offspring associated with impaired development of the central serotonin system in the brain. Further, it showed that introducing a healthy diet to the offspring at an early age failed to reverse the effect.

Previous observational studies in people had correlated maternal obesity with a range of mental health and neurodevelopmental disorders in children. The new research demonstrates for the first time that a high-fat diet, increasingly common in the developed world, caused long-lasting mental health issues for the offspring of nonhuman primates. “It’s not about blaming the mother,” said Dr. Sullivan.

“It’s about educating pregnant women about the potential risks of a high-fat diet in pregnancy and empowering them and their families to make healthy choices by providing support. We also need to craft public policies that promote healthy lifestyles and diets.”

Researchers assigned a total of 65 female Japanese macaques into two groups, one given a high-fat diet and one a control diet during pregnancy. Then they measured and compared anxiety behavior among 135 offspring and found that both males and females exposed to a high-fat diet during pregnancy exhibited greater incidence of anxiety compared with those in the control group. The scientists also examined physiological differences between the two groups, and found that exposure to a high-fat diet in early development impaired the development of neurons containing serotonin, a neurotransmitter that’s critical in developing brains.

Sullivan believes the findings provide evidence that mobilizing public resources to provide healthy food and pre- and post-natal care to families of all socioeconomic classes could reduce mental health disorders in future generations.