Baby Formula Linked to 'Obesity Hormone' Levels
Tue Jun 4, 1:31 PM ET

NEW YORK (Reuters Health) - Premature babies fed a nutrient-enriched formula have higher levels of the "obesity hormone" leptin as teenagers than similar children fed breast milk or standard formula, study findings indicate.

While the results are preliminary and do not show that such infant formula raises the risk of obesity, they suggest a mechanism by which concentrations of leptin, a hormone released by fat cells and other tissues that regulates appetite, may be set early in life.

The teens who were fed a nutrient-enriched formula in infancy were no more likely to be overweight than teens fed other types of food as babies. However, they did produce about 30% more leptin as their peers with similar amounts of fat tissue.

"Infancy, at least in preterm infants, could be a critical window for programming later leptin physiology and by inference the risk of obesity," Dr. Atul Singhal from the MRC Childhood Nutrition Research Centre in Cambridge, UK, and colleagues write.

The findings also contribute to a growing body of research into the relationship between prenatal and early childhood nutrition and the risk of obesity in adulthood.

Some studies have shown that inadequate nutrition in the first and second trimesters of pregnancy may increase the risk of obesity for offspring later in life, and others have reported a lower risk of obesity among adults who were breast-fed as infants.

Few studies have looked into the relationship between preterm infant formula, which is higher in calories than standard infant formula, and breast milk.

To investigate, the researchers measured leptin concentrations in 197 adolescents aged 13 to 16 years who had been born preterm, or before 37 weeks gestation. The adolescents weighed less than 1,850 grams (or 4 pounds) at birth and had taken part in an earlier study in which they had received a nutrient-enriched preterm formula or donated breast milk, or a preterm formula or regular infant formula, for one month.

The teenagers who had received the preterm formula had leptin concentrations that were higher relative to fat mass than those of their peers who had received breast milk or regular formula irrespective of age, overall body fat and social class. Breast milk in particular was associated with lower leptin levels from similar amounts of fat, the researchers report in the American Journal of Clinical Nutrition (news - web sites).

"Programming of relative leptin concentrations by early diet may be one mechanism that links early nutrition with later obesity," Singhal and colleagues conclude.

SOURCE: American Journal of Clinical Nutrition 2002;75:993-999.

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