Infants with plasma 25-hydroxyvitamin D [25(OH)D] over 75 nmol/L have a leaner body phenotype. The objective was to assess fat and lean mass accretion in infants with low vitamin D (LOW-D) status.
Term-born, breastfed infants from a dose-response study (Montreal, Canada) were categorized as LOW-D status (n=19) < 50 nmol/L at 1 mo of age and receiving 400, 800 or 1200 IU/d of vitamin D; and compared to a reference group with 25(OH)D > 50 nmol/L and receiving 400 IU/d of vitamin D. At 1 and 3 mo, measurements were anthropometry, body composition (dual-energy x-ray absorptiometry), plasma 25(OH)D (LC-MS/MS) and insulin like growth factor-1 (IGF-1; ELISA). Demographic and pregnancy information were surveyed.
At 1 mo, anthropometry and maternal characteristics were not different among groups. Plasma 25(OH)D at 1 mo was 37.0 (9.3) nmol/L in the LOW-D vs. 73.9 (19.1) nmol/L in the reference group. LOW-D infants that received 400 (n=7) to 800 IU/d (n=5) of vitamin D/d did not reach 75 nmol/L by 3 mo whereas 1200 IU/d (n=7) elevated 25(OH)D to above 75 nmol/L. Accretion of fat mass was greater, and lean mass lower, in LOW-D infants compared to the reference group; unless provided 1200 IU/d of vitamin D. IGF-1 declined more rapidly (LOW-D -31.2 vs reference -23.1 % change) in the LOW-D group.
Enhancing vitamin D status early in infancy may support a leaner body phenotype. Trials using higher dose vitamin D supplementation for neonates with low vitamin D status are required to confirm this hypothesis.