Is the "breast is best" mantra an oversimplification?

A 2015 meta-analysis of 23 high-quality studies with a sample size >1500 children and controlled for important confounders showed a pooled reduction in the prevalence of overweight or obesity of 13% (95% CI, 6-19).⁵⁷ The protection in this meta-analysis showed a dilution of the effect as the participants aged and an inverse relationship of the effect with sample size.

Breastfeeding is, therefore, unlikely to play a significant, if any, role in combatting the obesity epidemic.

Hypertension. A meta-analysis of high-quality trials demonstrates a <1 mm Hg reduction in systolic blood pressure and no significant difference in diastolic pressure in breastfed infants.⁵⁷ Similarly, no significant effect of breastfeeding on blood pressure has been demonstrated in trials of preterm infants.⁵¹

Type 2 diabetes. Available data are limited and heterogeneous for the association between breastfeeding and later development of type 2 diabetes. Only 2 high-quality trials were identified in the 2013 WHO meta-analysis, and their results conflict.⁵¹ A 2015 meta-analysis identified only 3 high-quality studies, without a statistically significant relationship.⁵⁷

Dyslipidemia. Although earlier data suggested an association between breastfeeding and reduced cholesterol levels later in life, the 2013 WHO meta-analysis and a 2015 meta-analysis concluded that no association exists. The limited data available for preterm infants conflict.^51,57

Growth. There is no evidence that feeding method has a short- or long-term effect on weight gain or length gain in preterm or term infants.^35,36,58

Death. No clear association has been found between mortality and breastfeeding status in developed countries, except for the association with SIDS.³⁵

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