Associations between Vitamin D Deficiency and Carbohydrate Intake and Dietary Factors in Taiwanese Pregnant Women.

This cross-sectional observation study investigated the vitamin D (VD) status in Taiwanese pregnant women and the effects of VD supplementation and macronutrient intake on serum 25-hydroxy-vitamin D (25[OH]D) level. Data on VD intake, daily sunlight exposure, and carbohydrate intake were obtained from 125 pregnant women at 30−37 weeks' gestation. Serum 25[OH]D level was measured before delivery in all enrolled women; and the mean 25(OH)D level was 43 nmol/L or 17.2 ng/mL. The 25(OH)D level was significantly correlated with total VD intake of pregnant women (r = 0.239; p = 0.007). The severe VD deficiency group (n = 16; mean of 25(OH)D level = 8.5 ng/mL) had significantly lower total VD intake and supplementation than the groups with VD deficiency (n = 69), insufficiency (n = 32), and sufficiency (n = 8). Those with ≥400 IU/day total VD intake (including VD from food and supplementation) had significantly higher 25(OH)D concentration than those with <400 IU/day total VD intake. Those with 400 IU/day VD supplementation could significantly increase serum 25(OH)D concentrations for pregnant women. Among 85 pregnant women with carbohydrate intake of ≥300 g/day, serum 25(OH)D levels were negatively correlated with carbohydrate intake (p = 0.031). In conclusion, VD deficiency was highly prevalent in Taiwanese pregnant women. VD supplementation was the most effective method for increasing 25(OH)D concentration in pregnant women. Higher carbohydrate intake might reduce 25(OH)D levels.

Effect of Oral Vitamin D3 Supplementation in Exclusively Breastfed Newborns: Prospective, Randomized, Double-Blind, Placebo-Controlled Trial.

Exclusively breastfed infants are at a high risk of vitamin D deficiency. Few studies have evaluated the effects of vitamin D supplementation. Hence, we conducted a prospective randomized controlled trial investigating the effects of oral vitamin D3 400 IU/d supplementation in exclusively breastfed newborns. Serum 25-hydroxy-vitamin D (25[OH]D) levels in pregnant women and their newborns were evaluated. Breastfed newborns were randomized to one of two regimens at age 10 days. One group received vitamin D3 supplementation at a dose of 400 IU/d (vD-400 group), whereas the placebo group received a liquid product without vitamin D3. Outcomes were assessed at 4 months of age. A total of 92 pregnant women and their infants were enrolled, and the data of 72 infants (37 in the vD-400 group and 35 in the placebo group) who completed the study at 4 months of age were assessed. The results showed severe vitamin D deficiency in 15.2% of mothers before delivery, while 54.3% had vitamin D deficiency. Moreover, 15.2% of newborns presented with severe vitamin D deficiency at birth, while 52.2% had vitamin D deficiency. Maternal vitamin D levels were significantly correlated with infant vitamin D levels at birth (r = 0.816, p < 0.001). At 4 months of age, weight, head circumference, serum 25(OH)D, phosphorus, and intact parathyroid hormone levels significantly differed between the vD-400 and placebo groups. However, the body length and bone mineral density of the two groups did not differ significantly. Regardless of vitamin D supplementation, participants with severe vitamin D deficiency had significantly higher intact parathyroid hormone levels and lower bone mineral content. In conclusion, among exclusively breastfed infants, oral supplementation with vitamin D3 at a dose of 400 IU/d from age 10 days increased 25(OH)D concentrations at 4 months of age, but it did not affect bone mineralization. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Metagenomic analysis of the gut microbiome composition associated with vitamin D supplementation in Taiwanese infants.

Early childhood is a critical stage for the foundation and development of the gut microbiome, large amounts of essential nutrients are required such as vitamin D. Vitamin D plays an important role in regulating calcium homeostasis, and deficiency can impair bone mineralization. In addition, most people know that breastfeeding is advocated to be the best thing for a newborn; however, exclusively breastfeeding infants are not easily able to absorb an adequate amount of vitamin D from breast milk. Understanding the effects of vitamin D supplementation on gut microbiome can improve the knowledge of infant health and development. A total of 62 fecal sample from healthy infants were collected in Taiwan. Of the 62 infants, 31 were exclusively breastfed infants and 31 were mixed- or formula-fed infants. For each feeding type, one subgroup of infants received 400 IU of vitamin D per day, and the remaining infants received a placebo. In total, there are 15 breastfed and 20 formula-fed infants with additional vitamin D supplementation, and 16 breastfed and 11 formula-fed infants belong to control group, respectively. We performed a comparative metagenomic analysis to investigate the distribution and diversity of infant gut microbiota among different types of feeding regimes with and without vitamin D supplementation. Our results reveal that the characteristics of infant gut microbiota not only depend on the feeding types but also on nutrients intake, and demonstrated that the vitamin D plays an important role in modulating the infant gut microbiota, especially increase the proportion of probiotics in breast-fed infants.