Breastfeeding in the Modern World.

BACKGROUND

Social changes in the 20th century resulted in substantial reductions in the prevalence of breastfeeding in many countries but especially in those with high and increasing wealth. Concerns about this decline prompted widespread research to quantify the benefits of breastfeeding and the mechanisms by which it exerts protective effects for mothers and children. Pro-breastfeeding advocacy resulted in the WHO International Code of Marketing of Breastmilk Substitutes in 1981 and the Innocenti Declaration on Breastfeeding in 1990, which, together with numerous other initiatives, have helped to turn the tide.

SUMMARY

A tranche of recent meta-analyses of dozens of individual studies provide very strong evidence that breastfeeding has substantial benefits to babies, infants, and young children. The benefits and strengths of association vary according to the background environmental and hygiene conditions in different settings. In low-income settings, the chief measurable benefits for the child are in respect of reductions in diarrhea and respiratory infections, and in mortality. In high-income settings, breastfeeding protects against otitis media, likely protects against type 2 diabetes and overweight and obesity, and possibly protects against type 1 diabetes. It likely improves IQ by 2-3 percentage points. In mothers, breastfeeding reduces a mother's likelihood of breast and ovarian cancers. Feeding these data into the Lives Saved Tool suggests that these benefits could prevent 823,000 deaths in children and 22,000 among women.