Formula-fed infants have significantly higher fat-free mass content in their bodies than breastfed babies

Aim Early nutrition may affect body composition development. This study assessed body composition changes in healthy term infants in the first four months of life, comparing the results for breastfed and formula-fed babies. Methods A longitudinal, observational study was conducted with healthy term infants, who had a birth weight of more than 2500 g and were aged up to 3 weeks at enrolment. Infants were either exclusively breastfed or formula-fed. Growth and body composition were assessed by air-displacement plethysmography at enrolment and 4 months. Results A total of 158 infants were enrolled (72 exclusively breastfed and 86 exclusively formula-fed). Body composition was similar between the two feeding groups at enrolment, but fat-free mass (4831 ± 538 g vs 4641 ± 461 g; p = 0.036) at 4 months and the fat-free mass changes between enrolment and 4 months (80.3 ± 16.4% vs 67.6 ± 18.4%; p < 0.001) were higher in formula-fed infants than breastfed ones. Conclusions Our findings suggest that formula-fed infants show different body composition development during the first 4 months of life to breastfed ones, with higher fat-free mass content. ©2014 Foundation Acta Pædiatrica. Published by John Wiley & Sons Ltd.