LLLI Center for Breastfeeding Information

Journal Abstract of the Month for June 2001

JAMA 01-5-06; 285(19):2461-67.

Title: "Risk of Overweight Among Adolescent Who Were Breastfed as Infants"

Author: Matthew W. Gillman et al.

The population of children who were the sons and daughters of subjects in the ongoing Nurses' Health Study II, a cohort study of over 116,000 female registered nurses, resulted in 15,341 participating boys and girls. Adolescents who were mostly or only fed breast milk vs mostly or only fed infant formula in the first six months were at an approximately 22% lower risk of being overweight. Inverse associations were also present between duration of breastfeeding and risk of overweight. Those breastfed for at least 7 months were approximately 20% less likely to be overweight than those breastfed for no more than 3 months. In addition, the apparent protective effects were larger with increasing duration of breastfeeding. The mechanisms which may explain this: It is possible that during infancy bottle feeding promotes more parental control and less self-regulation than breastfeeding. Another reason could be a lower serum concentration of insulin, a hormone that promotes fat storage, in breastfed infants than in infants fed cow's milk-based formula. Also, 80-90% of breast milk is consumed in the first 4 minutes, with the richer hindmilk consumed at the end of the feeding. Infancy may be a critical period for long-term effects of feeding and breastfeeding may program the infant to defend against later energy imbalance.

Keywords: Obesity/Weight Concerns, Advantages, Extended BF, Recall, BF-Duration, Long-term Advantages.