Genetic Variations in VDR could Modulate the Efficacy of Vitamin D3 Supplementation on Inflammatory Markers and Total Antioxidant Capacity among Breast Cancer Women: A Randomized Double Blind Controlled Trial

Abstract

Background: Low levels of vitamin D are found in a great part of breast cancer women. Study subjects using vitamin<br />D3 supplement had lower rates of cancers and fewer markers of inflammation. Additionally, recent studies demonstrate<br />the power of vitamin D supplementation to lower inflammation and oxidative stress biomarkers associate with VDR<br />polymorphism to reduce inflammation. This study was aimed to assess the impact of vitamin D3 supplementation on<br />the serum concentration of inflammatory markers and antioxidant capacity with regard to VDR polymorphism in the<br />VDR gene in breast cancer women. Methods: A randomized, double-blind, placebo-controlled trial was conducted on 56<br />breast cancer women. Participants were assigned to 2 treatment arms: placebo and vitamin D3 for 2 months intervention.<br />Supplementation group received 50,000 IU of vitamin weekly. Blood samples were collected at baseline and after<br />the intervention to measure the 25(OH) D3, TNF-α, TGF- β and TAC. Genotyping was performed for FokI, BsmI, ApaI,<br />and TaqI polymorphism. Results: After eight weeks supplementation, the intervention group showed a significant increase<br />in the serum concentration of 25(OH) D3 (28±2.6 to 39±3.5; p=0.004 and TAC (48.9±13.3 to 63.5±13.3; p= 0.017).<br />Changes in TNF-α, TGF- β1 were not significant. Serum TAC levels of participants with the TT/Tt, Ff genotypes were<br />more responsive to supplementation. Conclusions: Supplementation with a vitamin D3 increased the TAC in breast<br />cancer women, although it had no effect on inflammatory markers. Serum TAC in the TT/Tt, Ff were more responsive to<br />vitamin D supplement compared with those with the FF/ff and tt genotypes.