Higher fat mass and fat mass accretion during the first six months of life in exclusively breastfed infants.

Background: Early nutrition influences infant growth and body composition, which may play a role in the infant's metabolic programming. Breastfed infants appear to have higher fat mass than formula-fed infants, but most comparisons have been cross-sectional, and evidence is scarce. The aim of this study was to describe fat mass and fat mass accretion during the first six months of life and evaluate differences by type of feeding (OMS).

Methods: Prospective cohort of healthy pregnant women and their infants (Mexico City, 2009-2014). At 1 (T1), 3 (T2) and 6 (T3) months of age, fat mass (FM) (PEAPOD) and type of feeding (feeding questionnaire) were evaluated.

Results: We included 109 healthy infants (mean ± SD age: 39 ± 1.1 weeks; birthweight: 2959 ± 294 g). Exclusive/predominant breastfed (EBF) infants had higher FM at T2 and T3 compared with non-EBF (%FM T3: 29.7 ± 5.9% vs 24.7 ± 5.6%, respectively) (p < 0.05). All infants increased their FM throughout time (p < 0.001). EBF infants showed a significant higher FM accretion (β: 3.61; 95% CI: 1.57-5.66, p < 0.01); the difference was maintained after controlling for confounding variables.

Conclusions: Exclusive/predominant breastfeeding promotes higher accretion of FM during the first six months of life which could have an important effect in the programming of health outcomes later in life.