We studied the effects of a known amount of total-body ultra-violet-B light irradiation (1.5 M.E.D. equivalent to 30′ of sunshine at noon on a clear summer day in fair-skinned women) on both serum and breast milk concentrations of vit D3, vit D2, 25-OH vit D3, 25-OH vit D2 and 1,25(OH)2 vit D in 5 lactating Caucasian women. By 48 hrs post UV-E exposure, serum vit D3 increased from 1.0±0.2 (SEM) ng/ml to 22.9±5.4 ng/ml (p<0.01, paired t test), remaining increased up to 14 days (2.30±0.12 ng/ml, p<0.01). Simultaneously, breast milk vit D3 rose from 6 to 71 IU/L (p<0.02, range 34-148 IU/L) within 48 hr. of irradiation, remaining elevated up to 14 days (12 IU/L, p<0.05). Breast milk vit D3 correlated with serum vit D3 (r=0.91). 48 hrs post irradiation serum 25-OH vit D3 increased from 13.9±2.7 to 17.6±3.3 ng/ml (p< 0.05), peaking at 7 days (20.5±3.0 ng/ml, p<0.02) and remaining elevated at 14 days (20.3±3.2 ng/ml, p<0.05). There was no change in 25-OH vit D3 in breast milk post irradiation. There was no change in serum or milk vit D2, 25-OH vit D2, or 1,25(OH)2 vit D following irradiation. There was no correlation between breast milk fat (mean 3.4±2.4 [SD] g/dl) and milk vit D3 or its metabolites. We conclude that maternal UVB irradiation (and thus sunshine exposure) significantly increases vit D3 in human milk. Despite a rise in serum 25-OH vit D3, vit D3 is the only vitamin form which is readily transferred into human milk from maternal serum following maternal irradiation.
About this article
Cite this article
Greer, F., Hollis, B. & Tsang, R. THE EFFECTS OF MATERNAL ULTRAVIOLET-B IRRADIATION ON VITAMIN D CONTENT OF HUMAN MILK. Pediatr Res 18 (Suppl 4), 197 (1984). https://doi.org/10.1203/00006450-198404001-00623