Fit kids set stage for sweet life

Muscular youngsters become adults with a lower risk of diabetes, UH researchers find

Muscle growth during early childhood development can help fight fat and prevent obesity at older ages, University of Hawaii scientists concluded from experiments with mice.

They found that mice with enhanced muscle mass in early development accumulated less fat than those without muscle mass and were normal with no diabetes when given a high-fat diet in adult stages.

The research indicates that children need exercise in early development years to get muscle growth and sufficient nutrients to support muscle growth, Jinxing Yang said in an interview.

Yang and Baoping Zhao, molecular scientists in the Department of Human Nutrition, Food and Animal Sciences, College of Tropical Agriculture and Human Resources, did the research with Dr. Robert Wall, who is with the U.S. Department of Agriculture's research service in Beltsville, Md.

Yang said he and Wall were able to manipulate the myostatin gene, which inhibits muscle growth, to generate transgenic mice with increased skeletal muscle.

After a high-fat feeding trial for two months, the nonmuscular mice showed signs of beginning stages of diabetes, insulin resistance and glucose intolerance, the scientists reported.

But enhanced muscle mass helped to prevent obesity in mice even on high-fat diets, they said.

Physiological effects, such as increased insulin sensitivity, glucose utilization and metabolic hormone changes occurred when increased muscle growth reduced fat accumulation in adult ages, they reported.

Yang said the physiological changes resulting from muscle mass during the growing stages take dietary fat away from connective tissue serving as the major storage site for fat.

A national study shows 15 percent of 6- to 19-year-olds are overweight, and the number is increasing, compared with 5 percent 20 years ago, Dr. Anne Shovic, UH-Manoa associate professor of human nutrition and a registered dietitian, said in a news release on the mice research.

Children have a sedentary lifestyle with fewer opportunities for physical activity, and there is a 90 percent chance that an overweight child will be an overweight adult, she said.

Yang said the mice research suggests buildup of muscle mass in childhood "is extremely important in handling extra food consumption during adulthood."

Muscle is built up naturally to about 18 years of age, and more energy is required to maintain the muscle mass, as opposed to fat, he said.

Yang said the group is continuing research to try to understand mechanisms involved in fat reduction through skeletal muscle buildup. They are also studying how increased muscle changes two critical hormones, which could help to understand obesity and diabetes, he said.