New research suggests that a high-fat maternal diet during pregnancy and while breastfeeding could have significant and lasting detrimental effects on the brain function and behavior of children. The study is one of few basic science studies conducted to measure the direct effect of a high-fat maternal diet on the cognitive functioning on offspring. Results from this study, and others related to obesity and pregnancy, will be presented today during an oral presentation by author Kellie Tamashiro, PhD, Associate Professor of Psychiatry and Behavioral Sciences at Johns Hopkins University at 3:30pm ET at The Obesity Society Annual Meeting at ObesityWeekSM 2014 in Boston, Mass.

"Our results using an animal model suggest that a maternal high-fat diet during pregnancy and lactation could have significant and lasting effects on the brain, behavior and cognition of rat pups," said Dr. Tamashiro. "Rat offspring born to mothers on a high-fat diet not only have a strong preference for foods high in fat and weigh more, but also have impaired glucose tolerance and are less responsive to a standard appetite suppressant."

The study was conducted in rats, which included 24 pregnant subjects; 12 were fed standard chow and 12 were fed a high-fat diet, similar to the typical American diet. Researchers evaluated the behavior of the offspring through a variety of tests. The offspring of mothers fed the high-fat diet also weighed more, ate more, and had a stronger preference for high-fat foods. Further, they were less active, less responsive to amphetamine, and had impaired object recognition. The male offspring of mothers fed the high-fat diet showed altered gene expression in the hippocampus which persisted through adulthood. The researchers found similar effects in female rat offspring in the tests used.

"We know that high-fat diets are tied to increased risk for metabolic syndrome and obesity, which in turn are associated with decreased brain function," said TOS spokesperson Kelly Allison, PhD, Director of Education, Center for Weight and Eating Disorders and Associate Professor of Psychology in Psychiatry at the Hospital of the University of Pennsylvania Health System. "However, this is a rare study measuring the direct effect of high-fat diets of pregnant rats on the brain function of their offspring, and it provides further incentive for childbearing women to eat a varied and nutritious diet."

Dr. Tamashiro reinforced that more research is needed before extending these findings to humans. "While the data suggests we need to exercise caution when considering the implications of high-fat diets during pregnancy, we can't yet make that leap to apply these findings in animal models directly to humans," said Dr. Tamashiro. "More studies are needed in pregnant women to confirm what this research implies."

A second study to be presented at ObesityWeek looks further into the impact of maternal obesity and its influence on child body composition during the first six years of life, beginning at age three months. Aline Andres, PhD, Associate Professor in the Department of Pediatrics, Section of Developmental Nutrition at the University of Arkansas for Medical Sciences and researcher in the Arkansas Children's Nutrition Center and Arkansas Children's Hospital Research Institute in Little Rock, Ark., along with her colleagues, used technology that estimates both body fat percentage and bone mineral density to evaluate how both boys and girls born to mothers with obesity were impacted over the six-year evaluation period.

"Our findings confirm in humans what has been shown in animal models -- that maternal obesity has a more significant impact on the body composition of boys than girls," said Dr. Andres. "Boys born to women with obesity have on average 4 to 5% higher body fat from age two to six years as compared to boys born to lean or overweight mothers. This difference was not observed among girls. To our knowledge, this is the first study to identify this sexual dimorphism of body composition in a long-term clinical study."

According to the researchers, if future studies confirm these preliminary results, childhood obesity interventions may need to be different for boys and girls. Further, more research is needed with additional longitudinal measurements of offspring body composition to determine if these trends continue into adulthood.