Study 2: All mothers received 400 IU of vitamin D₃/day. Group 1 infants received 300 IU of vitamin D₃ daily; mothers received no additional supplement Group 2 mothers a received + 6000 IU of vitamin D₃ daily.

Study 3: Group 1 Maternal supplement 2000 IU vitamin D₂/day. Group 2 Maternal supplement 60,000 IU D₂ monthly. Infants were not supplemented or tested in study 3.

Study 4: Mothers and infants supplemented simultaneously at undefined levels.

consuming a daily intake of vitamin D up to 10 times the daily recommended intake. Study 2: There were significantly higher increases in maternal serum 25(OH)D levels for the high-dose-supplemented mothers than those taking 400 IU daily (p < 0.0028). The mean maternal 25(OH)D levels in the 6400 IU group rose quickly within the first month and stabilized after 3 months. Maternal 25(OH)D levels of those receiving 400 IU daily rose slightly, but still within the insufficient range. There was no significant difference between groups with infant mean 25(OH)D. Both groups of infants had increases from baseline 25(OH)D means, but still at insufficient levels. Considering levels were similar, this suggests that maternal supplementation of 6400 IU of vitamin D daily is equally effective as supplementing the infant with 300 IU of vitamin D daily. Human milk ARA correlated with the mother’s 25(OH)D level. Those taking 6400 IU/day showed significantly increased ARA (p < 0.0003). There was no evidence of toxicity in either group, based on serum calcium, phosphorus levels, and urine calcium/creatinine ratios. Study 3: Lactating women had significantly lower baseline 25(OH)D means compared to nulliparous women (p < 0.001). Although the serum 25(OH)D levels in lactating women increased significantly in both intervention groups (p < 0.001), the 25(OH)D levels reached greater than or equal to 50 nmol/L in only 35% of the daily dosage group and 20% of the monthly intervention group. Nulliparous women had similar results for sufficient levels of 25(OH)D (36% in the daily group and 33% in the monthly group). Monthly doses, with a spike of milk vitamin D levels within 24 hours of maternal dosing and then a rapid decrease of milk vitamin D levels, are significantly efficacious than daily dosing for maintaining adequate milk vitamin D levels. Monthly dosing may still be preferred in an extremely noncompliant patient population versus no supplementation at all. Study 4: 94% of infants were deficient at baseline. Combined maternal and infant supplementation increased the infant mean 25(OH)D levels by 33.2 nmol/L. A 64% reduction of vitamin D deficiency (p < 0.0001) was demonstrated without adverse effects. Mean 25(OH)D remained considerably below the insufficient level of 32 ng/mL. Mean ARA at baseline was undetectable (<20 IU/L) and increased to a median vitamin D level of 50.9 IU/L after 3 months of supplementation.

Taylor SN, Wagner CL, Hollis BW. Vitamin D supplementation during lactation to support infant and mother. J Am Coll Nutr. 2008, 27:690-701.

Reference [7]

Narrative Review

Negative

3 studies reviewed

Study 1: Group 1: 2000 IU vitamin D₃ maternal intake, Group 2: 400 IU vitamin D₃ infant intake.

Study 2: Group 1: 1600 IU vitamin D₂ + 400

Study 1 showed equivalent vitamin D status in the 2 infant comparison groups. Maternal supplementation of 1000 IU/day vitamin D₃ did increase serum 25(OH)D concentrations in infants to levels considered sufficient to avoid rickets. Study 2 found that mothers experienced significant increases in total circulating 25(OH)D concentrations and 25(OH)D₂, but there were decreases in 25(OH)D₃. The significant