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Effect of Daily Vitamin D Supplementation During Pregnancy on Vitamin D Status and Markers of Immune Function

Posted:  Friday, September 30, 2016

Impact of Prenatal Vitamin D Supplementation on Markers of Immune Function, Inflammation, and Clinical Outcomes

Inferior prenatal vitamin D status has been linked to adverse pregnancy and infant health outcomes. Vitamin D enhances both innate and adaptive immunity by promoting the development of FoxP3+ regulatory T (Treg) cells and IL-10+ CD4+ T cells. Vitamin D deficiency during pregnancy and its effects on immune function may result in conditions such as bacterial vaginosis, periodontal disease, preeclampsia, and preterm birth. This study published in The Journal of Nutrition investigated the effect of daily vitamin D supplementation during pregnancy on maternal vitamin D status and immune function markers linked to adverse pregnancy outcomes.

In this study, 57 pregnant women were randomised to receive either 2000 IU/d vitamin D3 (treatment group) or 400 IU/d vitamin D3 (control group) from <20 weeks until delivery. Parameters such as vitamin D status, markers of innate immunity and systemic inflammation, regulatory and inflammatory T cells, and clinical outcomes such as birth weight and maternal blood pressure were evaluated at 27 and 36 weeks of pregnancy.

At 36 weeks, the increase in vitamin D status was greater in the treatment group (from 81.1 nmol/L at baseline to 116 nmol/L) compared to the control group (from 69.6 nmol/L at baseline to 85.6 nmol/L). There was an increase in the levels of IL-10+ CD4+ T cells in the treatment group (36%) compared to the control group at 36 weeks. The increase in diastolic blood pressure was 1.3-fold lesser in the treatment group compared to the control group. In addition, an 8.6% increase in birth weight was seen in the treatment group. However, the differences in blood pressure and birth weight were not statistically significant.

The study concluded that daily supplementation with vitamin D at a dose of 2000 IU/d was effective in improving the vitamin D status in pregnant women compared to supplementation with vitamin D at a dose of 400 IU/d. In addition, higher vitamin D dosage is linked to an increase in regulatory T cell immunity that may subsequently prevent adverse outcomes related to excess inflammation.

News Source: Zerofsky MS, Jacoby BN, Pedersen TL, et al. Daily Cholecalciferol Supplementation during Pregnancy Alters Markers of Regulatory Immunity, Inflammation, and Clinical Outcomes in a Randomized Controlled Trial. The Journal of Nutrition. 2016:jn231480.