![]() ![]() To ensure a daily intake of 400 IU/day, the amount known to prevent rickets, it has for many years been recommended that breastfed infants receive 400 IU/day of supplemental vD ( 9). But total antirachitic activity is typically <100 IU/l and is often quite negligible ( 4, 5, 6, 7, 8). Breast milk provides native vitamins D 3 and D 2 as well as the respective 25-hydroxylated compounds. Infants are at risk of vD deficiency when endogenous production of vD is limited by dark skin pigmentation or by residence at a northern latitude. Exogenous (dietary) sources of vD 3 and vD 2 (ergocalciferol) can fully replace endogenously produced vD, and thus, play an important role in situations where endogenous production of vD is limited or absent. ![]() Genetic factors also exert strong effects on the vD status ( 3). This endogenous production is strongly influenced by environmental factors, such as the extent of sun exposure, geographic latitude and season of the year, and by subject characteristics such as skin pigmentation ( 1, 2). Vitamin D (vD) is produced (cholecalciferol, vD 3) in the skin upon exposure to uvB radiation. The findings support the recommended dose of 400 IU/d, and stress the need to start supplementation at birth. ![]() The higher doses were somewhat more efficacious in maintaining vD sufficiency in breastfed infants. The four doses of vD produced different plasma levels of 25(OH)D. Low levels were common, with 7.8% of levels being <50 nmol/l and 15 infants having 2 to 4 low levels. There were no effects of vD on illness incidence or growth. Overall, levels of 25(OH)D differed significantly in proportion to vD dose. ![]() Most infants had low (<50 nmol/l) 25(OH)D levels at 1 mo, but with supplementation levels rose. The study was conducted during winter at 41° N. The primary endpoint was plasma 25(OH)D level, and secondary outcomes were plasma parathyroid hormone and calcium, and illness incidence. The supplements provided daily 200 IU, 400 IU, 600 IU, or 800 IU of vD. Methods:Įxclusively breastfed infants ( N = 213) were randomized at 1 mo to one of four doses, which they received through 9 mo while receiving no formula. This double blind trial evaluated four different doses of vD. Breastfed infants require supplementation with vitamin D (vD), but little is known about the necessary dose. ![]()
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