HEALTH NEWS

Study Title:

Junk Food Begets Junk Food, Generation to Generation

Study Abstract

Individuals exposed to high-fat, high-sugar diets before birth have an increased risk of obesity in later life. Recent studies have shown that these offspring exhibit increased preference for fat, leading to suggestions that perinatal exposure to high-fat, high-sugar foods results in permanent changes within the central reward system that increase the subsequent drive to overconsume palatable foods. The present study has determined the effect of a maternal “junk-food” diet on the expression of key components of the mesolimbic reward pathway in the offspring of rat dams at 6 wk and 3 mo of age. We show that offspring of junk-food-fed (JF) dams exhibit higher fat intake from weaning until at least 3 mo of age (males: 16±0.6 vs. 11±0.8 g/kg/d; females: 19±1.3 vs. 13±0.4 g/kg/d; P<0.01). mRNA expression of μ -opioid receptor (Mu) was 1.6-fold higher (P<0.01) and dopamine active transporter (DAT) was 2-fold lower (P<0.05) in JF offspring at 6 wk of age. By 3 mo, these differences were reversed, and Mu mRNA expression was 2.8-fold lower (P<0.01) and DAT mRNA expression was 1.9-fold higher (P<0.01) in the JF offspring. These findings suggest that perinatal exposure to high-fat, high-sugar diets results in altered development of the central reward system, resulting in increased fat intake and altered response of the reward system to excessive junk-food intake in postnatal life.—Ong, Z. Y., Muhlhausler, B. S. Maternal “junk-food” feeding of rat dams alters food choices and development of the mesolimbic reward pathway in the offspring.

From press release:

A new research report published online in The FASEB Journal suggests that pregnant mothers who eat high sugar and high fat diets have babies who are likely to become junk food junkies themselves. According to the report, which used rats, this happens because the high fat and high sugar diet leads to changes in the fetal brain's reward pathway, altering food preferences.

Not only does this offer insight into the ever-increasing rate of human obesity, but it may also explain why some people easily resist fatty and sugary foods, while others seem hopelessly addicted.

"These results will help us to better help women about diet during pregnancy and breastfeeding for giving their infants the best start in life," said Beverly Muhlhausler, Ph.D., co-author of the study from the FOODplus Research Centre in the School of Agriculture Food and Wine at the University of Adelaide in Adelaide, Australia.

To make this discovery, Muhlhausler and colleagues studied two groups of rats, which during pregnancy and lactation, were either fed standard "rat chow" or a junk food diet made up of a selection of common human foods high in fat and high in sugar. After the baby mice were weaned, the pups from both groups were allowed to select their own diets from either the same range of junk food or the standard rat chow. Brains from some of the pups also were collected at different times after birth and measured for the levels of the "feel good" chemicals (dopamine and opioids) and the receptors that these chemicals act upon. The scientists found that the group of rats whose mothers had eaten the junk food diet had higher levels of the receptor for opioids after they were weaned. This group also chose to eat more of the fatty foods as compared to the pups whose mothers ate the standard rat chow. This suggests that infants whose mothers eat excessive amounts of high-fat, high-sugar junk foods when pregnant or breastfeeding are likely to have a greater preference for these foods later in life.

"How ironic that your mother nags you to eat your fruits and vegetables, but it could have been her actions that helped you to prefer junk food!" said Gerald Weissmann, M.D., Editor-in-Chief of The FASEB Journal. "Perhaps in the future, studies like these will convince pregnant moms to go heavier on the green vegetables and a little lighter on the ice cream and Twinkies."

Study Information

.Z. Y. Ong, B. S. Muhlhausler
Maternal "junk-food" feeding of rat dams alters food choices and development of the mesolimbic reward pathway in the offspring.
The FASEB Journal,
2011 March
Sansom Institute for Health Research, School of Pharmacy and Medical Science, University of South Australia, Adelaide, South Australia, Australia