The Journal: Epidemiology

The Study: Breast-fed babies are less likely than bottle-fed infants to become fat when they grow up. In a new study of 5,614 youngsters between the ages of 9 and 14, investigators at the Harvard School of Public Health found that the longer children were breastfed in infancy, the less likely they were to become overweight or obese by adolescence. For every additional 3.7 months a child was breast fed, he or she had a 6% lower risk of ending up heavy.

What it means: Previous studies have suggested that breastfeeding may protect against later obesity. But results have been inconsistent and the association between breastfeeding and obesity could often be explained by underlying socio-cultural factors, like education and income. For example, well-educated, wealthy mothers tend to breastfeed, and their children also tend not to be obese. Is it the breastfeeding or the fact they are part of a well-to-do environment?

In this study, however, researchers controlled for such factors by comparing children with their own brothers and sisters—the 5,614 subjects were siblings from 2,709 families—and found that breastfeeding had the same protective effect within families and in the general population.

Bottom line: Most health organizations recommend that babies should be breastfed exclusively for the first 6 months of life.

From Our Archive:
03/07/2000 Is the Breast Connected to the Brain?
09/17/2001 Pumping it Up