Effects of Vitamin D3 and Calcium Supplementation on Serum Levels of Tocopherols, Retinol, and Specific Vitamin D Metabolites

Abstract

γ-Tocopherol (γT) protects against DNA-damaging effects of nitrogen oxides, yet its physiologic regulation in vivo is unknown. Observational studies indicate inverse associations of 25[OH]-vitamin D with γT and leptin. To determine whether vitamin D3 supplementation alters levels of lipid-soluble micronutrients, serum samples (N = 85 subjects) from a randomized, double-blind, placebo-controlled clinical trial of vitamin D3 (800 IU) and calcium (2 g), alone and in combination, were analyzed for lipid micronutrients and specific vitamin D metabolites at baseline and after 6 mo of supplementation. Serum 25[OH]-vitaminD3 levels increased 55% (P < 0.0001) and 48% (P = 0.0005), whereas 25[OH]-vitaminD2 levels were lower by 48% (P = 0.26) and 21% (P = 0.36) in the vitamin D3 and vitamin D3 plus calcium groups, respectively. At baseline, γT levels were inversely associated with 25[OH]D (r = −0.31, P = 0.004). With vitamin D3 plus calcium treatment, serum α-tocopherol decreased 14% (P = 0.04), whereas similar changes in γT (19% lower, P = 0.14) were observed. No significant effects were observed for D3 supplementation on leptin or retinol levels. These results are consistent with the hypothesis that vitamin D3 ± calcium affects serum tocopherol and 25[OH]D2 levels; however, studies using larger, more homogeneous populations are warranted.