New research examining the relationship between infant feeding and childhood obesity suggests that breastfeeding may have a protective effect.
Using data from approximately 15,000 participants in the Nurses Health Study II, Harvard researchers found that those children who were exclusively or mostly fed on breastmilk for the first six months of life had a significantly lower risk of being overweight when they reached adolescence (ages 9-14 years) (J Am Med Assoc, 2001; 285: 2461-67).
Another survey in the same journal failed to find such a strong association between breastfeeding and obesity. However, the accompanying editorial noted that this latter study may not be as conclusive since the size of the sample population (2685 children) and the number of women who breastfed exclusively for six months (31 per cent) were relatively small.
Also, this survey measured the effects on obesity at a younger age at three to five years. The protective effect of breastfeeding, say the authors, may take longer than that to become apparent (J Am Med Assoc, 2001; 285: 2453-60).