Father's diet before conception affects offspring's body fat in mice

(Press-News.org) SAN FRANCISCO—- When fathers eat a high-fat diet before conception of offspring, the male offspring have increased body weight after weaning and high body fat in midlife despite eating a low-fat diet, a new study in mice finds. The results were presented Sunday at The Endocrine Society's 95th Annual Meeting in San Francisco.

"Many researchers have studied the effects of maternal diet on the risk of obesity in their children. We found that the father's diet also affects the offspring in ways that are inherited," said the study's principal investigator, Felicia V. Nowak, MD, PhD, associate professor of molecular endocrinology at Ohio University in Athens.

The inherited differences in metabolism in the offspring of obese fathers appear to be epigenetic—changes in how genes are expressed that are "not hardwired" into the genes, meaning that they are modifiable by internal and external environmental factors, Nowak said. The cause of these changes was not behavioral because the offspring did not observe what their fathers ate nor did they have access to a high-fat diet, she noted.

In their study, the researchers fed male mice a 13-week diet that was either high fat (45 percent of calories derived from fat) or low fat (10 percent of calories from fat; control mice) but contained the same number of calories. The mice that ate the high-fat food became obese. All mice were mated with females that had received the matched low-fat diet. All their offspring received standard laboratory mouse chow.

The mouse pups underwent testing of their body weight and fat at various ages: 20 days, which was right after weaning and is similar in age to human infants or toddlers, according to Nowak; 6 weeks, which is roughly equivalent to adolescence; 6 months, or young adulthood; and finally 12 months, or older adulthood.

Compared with offspring from control mice, the male offspring of paternal mice with diet-induced obesity had higher body weight starting at 6 weeks of age, and the increased weight was still present at 6 and 12 months, the authors reported. In addition, at 6 months, the male offspring of the obese paternal mice had a higher percentage of total body fat than control offspring did. There were, however, no observed differences in the amount of brown fat, the calorie-burning fat that both rodents and humans have.

Surprisingly, male offspring of the high-fat-fed paternal mice also showed increases in voluntary running at 6 weeks. Female offspring ran more than male offspring at 6 months and 12 months, Nowak said. She said they are studying possible causes for this behavior, which might offset the increased body fat and reduce the offspring's risk of metabolic disease such as diabetes and heart disease.

"Increasing numbers of children and adolescents are affected by obesity," Nowak said. "It is essential that we identify markers for early detection and prediction of obesity and diabetes. This will enable individuals to make healthy lifestyle choices and receive targeted health care interventions to delay or prevent the related disabilities and increase life expectancy."

Ohio University and its Heritage College of Medicine provided grant funding for this study.

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Founded in 1916, The Endocrine Society is the world's oldest, largest and most active organization devoted to research on hormones and the clinical practice of endocrinology. Today, The Endocrine Society's membership consists of over 16,000 scientists, physicians, educators, nurses and students in more than 100 countries. Society members represent all basic, applied and clinical interests in endocrinology. The Endocrine Society is based in Chevy Chase, Maryland. To learn more about the Society and the field of endocrinology, visit our site at http://www.endocrine.org. Follow us on Twitter.