Association of 6 months of exclusive breastfeeding with higher fat-free mass in infants in a low-resource setting with high HIV prevalence in South Africa.

Exclusive breastfeeding for 6 months is recommended by the World Health Organisation (WHO) for optimal health and growth of infants, but it is not a common practice in South Africa. A breastfeeding counselling programme was run to inform, encourage and support mothers to exclusively breastfeed their infants for 6 months, and mother-infant pairs were invited to participate in a research project to determine breast milk intake volumes using the dose-to-mother deuterium dilution stable isotope technique. This technique yields objective measurements of breast milk intake volumes and also enables determination of exclusivity of breastfeeding, which is most frequently determined by maternal recall and can be subject to bias. Exclusivity of breastfeeding at 6 weeks, 3 months and 6 months following birth of the infants was correlated with infant fat-free mass at 12 months, which was determined by the dose-to-infant deuterium dilution stable isotope technique. Results showed that infants who were exclusively breastfed for 6 months had a higher per cent fat-free mass at 12 months compared with infants who were not exclusively breastfed for 6 months (P < 0.05). This objective determination of both breastfeeding patterns and infant body composition gives weight to the WHO recommendation of exclusive breastfeeding for 6 months as it demonstrated adequate fat-free mass in infants at 12 months, even in an area with high HIV prevalence.