Recommendation for 6 months of exclusive breastfeeding examined

A controversial new analysis suggests that introduction of solid foods before 6 months of age may reduce the risk of allergies and iron deficiency anemia compared with exclusive breastfeeding. The researchers suggest that weaning should occur as early 4 months.

Experts in infant and child nutrition in the United Kingdom reviewed the evidence for and against exclusive breastfeeding for 6 months as recommended by the World Health Organization (WHO) in 2001. Results of their analysis were published in the British Medical Journal.

A review of 14 observation and 2 randomized studies (7 of which were from developing countries) served as the basis for the WHO’s 2001 recommendation. WHO concluded that babies who were breastfed exclusively for 6 months had fewer infections, with no harm on growth but with a potential risk of iron deficiency anemia.

From this, the investigators of the new analysis support that the recommendation for exclusive breastfeeding for 6 months is appropriate in developing countries, but they note that another review of 33 studies, conducted at the same time that WHO did its review, found “no compelling evidence to support change from the then-existing recommendation to introduce solids at 4 to 6 months.”

Evidence since the 2001 WHO recommendation indicates that longer durations of exclusive breastfeeding reduced the risk of hospital admission for infant infections and that infants who were breastfed exclusively for longer than 6 months had fewer cases of pneumonia and recurrent otitis media.

Other data imply that 6 months of breastfeeding may not provide adequate nutrition. A 2007 study in the United States found an increased risk of anemia among infants breastfed for 6 months compared with those in whom solids were introduced at 4 to 5 months.

Swedish researchers found that the incidence of early onset celiac disease increased after a recommendation to delay introduction of gluten until age 6 months but fell back to previous levels after the recommendation reverted to 4 months.

A study with 6.5 years of follow-up found higher levels of fatness in babies breastfed exclusively for 6 months versus 3 months, with no differences between groups in cognition, blood pressure, dental cavities, and atopy.

Fewtrell M, Wilson DC, Booth I, Lucas A. Six months of exclusive breastfeeding: how good is the evidence? BMJ. 2011;342:c5955.