Location: Children's Nutrition Research CenterTitle: Association of infant feeding with trajectories of body composition and growth
|BELL, KATHERINE - Boston Children'S Hospital|
|WAGNER, CAROL - Medical University Of South Carolina|
|FELDMAN, HENRY - Boston Children'S Hospital|
|SHYPAILO, ROMAN - Children'S Nutrition Research Center (CNRC)|
|BELFORT, MANDY - Brigham & Women'S Hospital|
Submitted to: The American Journal of Clinical Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/6/2017
Publication Date: 6/6/2017
Citation: Bell, K.A., Wagner, C.L., Feldman, H.A., Shypailo, R.J., Belfort, M.B. 2017. Association of infant feeding with trajectories of body composition and growth. American Journal of Clinical Nutrition. doi:10.3945/ajcn.116.151126.
Interpretive Summary: Formula-fed infants gain more weight out of proportion to length in the first year of life than breastfed infants. This results in a higher weight-for-length and BMI. Understanding the relation between breastfeeding and body fat gain during infancy may provide insight into the link between breastfeeding and a reduced risk of later-life obesity. To our knowledge, there are no large contemporary longitudinal studies comparing gains in fat and lean mass between formula-fed infants and breastfed infants. We studied data collected during a randomized trial of maternal vitamin D supplementation. 214 breastfed infants and 62 formula-fed infants were measured at 1, 4, and 7 months of age. We determined infant body composition using DXA. DXA provided measurements of fat and lean mass, and body fat percentage. Compared to breastfed infants, formula-fed infants gained more in weight and BMI through 7 months of age. There was no difference in linear growth. Formula-fed infants gained more lean mass than breastfed infants, but not fat mass. Our study demonstrates that compared with predominantly breastfed infants, formula-fed infants have substantially greater lean mass. This is detectable as early as 3 months of age. This lack of excess body fat gain in formula-fed infants contradicts the idea that accumulating excess body fat during infancy is behind the association of infant formula feeding with later-life obesity. Overall, there appears to be very little if any association of infant feeding mode with body fat gains during early infancy. Thus, the link between early formula feeding and later obesity may need to be explained by reasons other than excess body fat gain.
Technical Abstract: The extent to which breastfeeding is protective against later-life obesity is controversial. Little is known about differences in infant body composition between breastfed and formula fed infants, which may reflect future obesity risk. We aimed to assess associations of infant feeding with trajectories of growth and body composition from birth to 7 mo in healthy infants. We studied 276 participants from a previous study of maternal vitamin D supplementation during lactation. Mothers used monthly feeding diaries to report the extent of breastfeeding. We measured infants’ anthropometrics and used dual-energy X-ray absorptiometry to assess body composition at 1, 4, and 7 mo. We compared changes in infant size (z scores for weight, length, and body mass index [BMI (in kg/m2)]) and body composition (fat and lean mass, body fat percentage) between predominantly breastfed and formula-fed infants, adjusting in linear regression for sex, gestational age, race/ethnicity, maternal BMI, study site, and socioeconomic status. In this study, 214 infants (78%) were predominantly breastfed (median duration: 7 mo) and 62 were exclusively formula fed. Formula-fed infants had lower birth-weight z scores than breastfed infants (-0.22 ± 0.86 and 0.16 ± 0.88, respectively; P < 0.01) but gained more in weight and BMI through 7 mo of age (weight z score difference: 0.37; 95% CI: 0.04, 0.71; BMI z score difference: 0.35; 95% CI: 0, 0.69), with no difference in linear growth (z score difference: 0.05; 95% CI: -0.24, 0.34). Formula-fed infants gained more lean mass (difference: 303 g; 95% CI: 137, 469 g) than breastfed infants, but not fat mass (difference: -42 g; 95% CI: -299, 215 g). Formula-fed infants gained weight more rapidly and out of proportion to linear growth than did predominantly breastfed infants. These differences were attributable to greater accretion of lean mass, rather than fat mass. Any later obesity risk associated with infant feeding does not appear to be explained by differential adiposity gains in infancy.