Vitamin d receptor fok-i polymorphism modulates diabetic host response to Vitamin D Intake

Abstract

OBJECTIVEdInterpopulation as well as interindividual variations in response to vitamin D intake commonly observed in subjects with type 2 diabetes may be related to genetic makeup. One of the candidate genes potentially responsible for this diversity is vitamin D receptor (VDR). This study aimed to investigate the interactive effect of VDR Fok-I polymorphism and vitamin D intake on diverse aspects of diabetic host response. RESEARCH DESIGN AND METHODSdGlycemic status, lipid profiles, inflammatory biomarkers, and VDR Fok-I genotypes were determined in diabetic subjects (n = 140) who participated in a randomized controlled trial. Participants consumed two 250-mL bottles per day of yogurt drink (doogh) fortified with 500 IU vitamin D/250 mL for 12 weeks. RESULTSdMean serum25(OH)Dincreased by ~30 nmol/L (P,0.001). The time3intervention effect was significant for 25(OH)D (P = 0.030),HDL (P = 0.011), high-sensitivity C-reactive protein (hsCRP) (P < 0.001), interleukin (IL)-4 (P = 0.008), and IL-6 (P = 0.017) among the genotypic groups. The alleles were defined as F or f depending on the absence or presence of the restriction site, respectively. The least increment in 25(OH)D was in ff (23.0 6 3.8 nmol/L) compared with Ff (31.2 6 3.4 nmol/L) and FF (35.6 6 2.7 nmol/L) (P for trend = 0.009), but only the difference between ff and FF was significant (P = 0.023). FF group had the largest decrement of both hsCRP and IL-6 compared with Ff (P < 0.001 and P = 0.038) and ff (P = 0.010 and P = 0.048), respectively. CONCLUSIONSdWe concluded that those of VDR ff genotype may be regarded as "low responders" to vitamin D intake in terms of response of circulating 25(OH)D and certain inflammatory biomarkers. A nutrigenetic approach may, therefore, be needed to protect diabetic patients from vitamin D deficiency. Copyright © 2013 by the American Diabetes Association.