Hormone May Explain African-American Girls' Higher Metabolism

African-American teen-age girls tend to be taller and heavier and to mature faster than their peers in other ethnic groups. A newly published study of 136 healthy, 8- to 17-year old girls suggests one possible reason for this. African-American girls in the study had higher blood levels of leptin, a hormone that helps cue “fullness.”

Manufactured in fat tissue, leptin is a biochemical cue for curbing appetite and burning calories. It and another hormone--neuropeptide-Y, which triggers hunger--help control the cycle of hunger and satiety.

Leptin levels in blood may be higher in some individuals, so their bodies require more to “hear” its biochemical message, according to pediatric researcher William W. Wong at the Children's Nutrition Research Center in Houston, Texas. The center is administered by the Agricultural Research Service and Baylor College of Medicine. ARS is the chief research agency of the U.S. Department of Agriculture.

The new study helps fill gaps in data on energy metabolism in the African-American population. Wong expressed gratitude to the 79 white and 57 African-American girls--all Houston area students--who participated as volunteers.

Medical research has suggested that higher leptin levels may speed sexual maturity and make the body better at conserving energy. Higher energy efficiency could help explain why African- American girls grow faster than peers in other ethnic groups.

This metabolic efficiency can backfire in adulthood by contributing to obesity and increased health risk. But the new study adds further evidence that establishing healthy life styles in childhood can have lasting beneficial effects into adulthood.

The study was published in the October Journal of Clinical Endocrinology and Metabolism.

Scientific contact: William W. Wong, ARS Children's Nutrition Research Center, Houston, Texas, phone (719) 798-7168, fax (719) 798-7119, wwong@bcm.tmc.edu