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Leptin Targeted in Research on Obesity, Pregnancy

Intent on helping Americans fight obesity, Agricultural Research Service scientists are probing the role that leptin--a protein--plays in regulating appetite and weight gain. Janet C. King and Ratna Mukherjea at the ARS Western Human Nutrition Research Center, Davis, Calif., are using results from their preliminary study of leptin levels in breastfeeding moms to design an expanded investigation with pregnant and lactating women.

Their earlier study showed that mothers who ate more carbohydrates in relation to fat during the months they were breastfeeding had higher levels of leptin in their blood. That's in contrast to lactating moms who ate more fats than carbs--the exact opposite of what's recommended in U.S. Department of Agriculture's dietary guidelines.

Higher leptin levels may help trim pounds gained during pregnancy. Leptin, made by the body's fat cells, is thought to help contribute to satiety, a feeling of fullness.

King and Mukherjea's findings are based on their statistical review, known as a multivariate analysis, of food records and blood leptin levels of 47 volunteers, aged 20 to 40. The scientists collaborated with researchers from the University of California, Davis, and University of Maryland, College Park.

Their results about fats, carbs and leptin agree with those from a study led by physiologist Peter J. Havel of the University of California, Davis. Havel analyzed food choices and leptin levels of 19 normal-weight, nonpregnant females, aged 20 to 43. But the lactating moms experiment that King and Mukherjea led apparently is the first to look at leptin levels in postpartum women.

Women who, during pregnancy, exceed the rate and total amount of weight gain recommended in guidelines from the National Academy of Sciences' Institute of Medicine are more likely to have complications just before or after delivery, and to retain the excess weight. Overweight has been linked to increased risk of diabetes, heart disease, stroke and certain cancers.

ARS is the U.S. Department of Agriculture's chief research arm.