Breastfeeding infants during the first 4-6 months of life may offer some protection against overweight in childhood. This finding comes out of the European-wide study IDEFICS (Identification and prevention of Dietary- and lifestyle-induced health EFfects In Children and infantS), and supports current recommendations for breastfeeding.
The World Health Organization recommends that mothers breastfeed exclusively – that is, nourish their child with breast milk only – for the first six months of life. This is based on evidence that breastfed infants have a lower risk of disease, including gastrointestinal disorders and lower respiratory tract infections. The link between breastfeeding and overweight, however, remains unclear.
To elucidate the effect exclusive breastfeeding has on a child’s risk of becoming overweight, researchers looked at data from the IDEFICS study on 14,726 children from eight European countries. There were roughly equal numbers of boys and girls, aged between 2 and 9 years. Researchers assessed the children’s body mass indices, waist-to-height ratios, and body fat percentages. They also collected information on breastfeeding duration, and on variables such as maternal overweight, maternal education, household income, and family structure.
Their analysis of this data suggests that exclusive breastfeeding for 4-6 months can lower the risk of childhood overweight, with a full 6 months’ breastfeeding offering the greatest protection. This relationship holds true even after adjusting for variables such as age, gender, country, and maternal and familial factors. A shorter duration of breastfeeding (1-3 months) did not offer any significant protection against overweight, and a longer duration (7-12 months) did not provide any additional protection.
A number of possible explanations exist for why breastfeeding may lower the risk of overweight in childhood. First, it has been proposed that breastfeeding allows infants to respond to internal hunger cues rather than external ones. Second, breastfeeding may influence levels of hormones such as insulin which, in turn, may have an effect on obesity later on in childhood. Finally, research suggests that gut function and with it nutrient utilisation is modulated by diet. Given that the composition of breast milk is different to formula, and changes according to the period of lactation, this may explain part of the observed variation. However, all this does not mean that having to rely on formula destines a child to become overweight.
The authors recognise some limitations to their research; namely, the reliance on parental recall of feeding practices, and the fact that their findings are not representative on a country level. However, they used a large and diverse population and were able to control for a large number of variables. Their study provides some interesting insight into the link between breastfeeding and childhood overweight, and supports current recommendations to exclusively breastfeed infants for the first six months of life.
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