Scientists from the US Department of Agriculture's Agricultural Research Service (ARS) are probing the role that the protein leptin plays in regulating appetite and weight gain, in a bid to stem the worrying rise in obesity among Americans.
Researchers at the ARS Western Human Nutrition Research Center in Davis, California are using results from their preliminary study of leptin levels in breastfeeding mothers 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. This contrasts to lactating mothers who ate more fats than carbohydrates - the exact opposite of what is recommended in the US 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.
The findings are based on the researchers' 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, carbohydrates 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, non-pregnant females, aged 20 to 43. But the initial lactating mothers experiment is apparently 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.
The ARS is the US Department of Agriculture's chief research arm.