This is a guest post thanks to Dr Arya Sharma, Professor of Medicine & Chair in Obesity Research and Management at the University of Alberta, Edmonton, Canada. Visit his Obesity Notes website at http://www.drsharma.ca/
Regular readers may recall a recent post on the efforts to increase breast feeding in Canada. Notably, a recent media report had NYCs Mayor Bloomberg (of banning oversize pop fame) to demand that clinics lock up baby formula in an attempt to increase breast feeding, as a further measure to prevent obesity.
But how long should infants be breast fed to prevent obesity?
This question was addressed in a paper by Hunsberger and colleagues from 8 European countries (Italy, Estonia, Cyprus, Belgium, Sweden, Hungary, Germany and Spain) published in Public Health Nutrition.
The researchers assessed the potential impact of exclusive breast-feeding on childhood overweight in cross-sectional datathe longitudinal cohort study IDEFICS. The analysis included 14 726 children aged 2-9 years for whom early feeding practices were reported by parents in standardized questionnaires.
After controlling for education, income and other potential confounders, breast-feeding exclusively for 4-6 months were about 30% less likely to be overweight when compared with children never exclusively breast-fed. This association could not be explained by socio-economic characteristics or maternal overweight.
Thus, the authors conclude that exclusive breast-feeding for 4-6 months may confer protection against overweight in addition to other known benefits. Exclusive breast feeding beyond 6 months did not appear to have any additional benefit in this regard.
While association studies do not prove causality, there are certainly a number of biologically plausible hypotheses that would explain the beneficial effect of breast feeding on the development of childhood obesity, so certainly this is a finding that should not be simply dismissed.
I wonder though how feasible exclusive breastfeeding for 4-6 months would actually be in most settings.