Background: Early feeding choices may affect long-term health outcomes. Therefore, understanding body composition changes in healthy breastfed infants has become an important research focus.
Objectives: The aims of this review were to investigate the body composition changes that occur during weight loss in breastfed term newborns and to examine body composition differences between exclusively/predominantly breastfed and exclusively formula-fed infants in the first 6 months of life.
Methods: We performed a review of the existing literature using PubMed. We searched for studies published in English since January 1, 2000, that involved human infants ranging in age from birth to 6 months. We used the following MEDLINE Medical Subject Headings: ((breastfeeding) OR (infant formula)) AND ((body composition) OR (bioelectrical impedance) OR (absorptiometry, photon) OR (total body potassium) OR (isotope dilution) OR (air-displacement plethysmography)). Our search yielded 6 studies.
Results: Two studies reported that newborn weight loss was due to a reduction in the quantity of both fat mass and fat-free mass. Three out of 4 articles that evaluated body composition changes according to method of feeding reported no differences in body composition between exclusively/predominantly breastfed and exclusively formula-fed infants in the first 4.5 months of life. One study reported that exclusively breastfed infants at 3 months of age and exclusively breastfed boys at 6 months of age had higher fat mass contents compared to exclusively formula-fed infants.
Conclusion: Because of the limited number of studies available, larger studies are needed to clarify the differences in body composition between exclusively/predominantly breastfed and exclusively formula-fed infants.
Keywords: body composition; breast milk; breastfeeding; full-term infants; growth.