Background and Objectives: Emerging data suggest an association between low serum concentrations of 25(OH)D and central obesity. This study aimed to investigate the effect of daily intake of vitamin D-fortified yogurt drink (doogh) on central obesity indicators in subjects with type 2 diabetes (T2D) and the possible modulation of this effect by vitamin D receptor (VDR)-Cdx-2 genotypes.

Materials and Methods: Sixty T2D subjects were randomly allocated into two groups to receive either plain doogh (PD; n=29, containing 170 mg calcium and no vitamin D/250 mL) or vitamin D3-fortified doogh (FD; n=31, containing 500 IU/250 mL) twice a day for 12 weeks. 25(OH)D, glycemic and adiposity indicators were evaluated before and after the intervention. VDR genotypes in the extended number of T2D subjects were determined in the FD group (n=60).

Results: After 12 weeks, in the FD compared to the PD group, serum 25(OH)D increased (+35.4 nmol/L vs. -4.8 nmol/L, p<0.001) and mean changes of waist circumference (WC; -1.3 vs. +1.6 cm, p=0.02), body fat mass (FM; -5.1 vs. +0.60 %, p<0.001), truncal fat (TF; -1.1 vs. 0.13%, p=0.003) and visceral adipose tissue (VAT; -0.80 vs. +0.37 a.u., p<0.001) decreased significantly. Circulating 25(OH)D was raised only in AA group (34.8 nmo/L in the AA group vs. -6.4nmol/L in the AG and -1.6nmol/L in the GG groups, p<0.001). This difference was accompanied by a significant decrease in the changes of WC (p=0.004), FM% (p<0.001) and TF% (p<0.001) in AA genotype.

Conclusions: Daily intake of 1000 vitamin D-fortified doogh for 12 weeks improved the central obesity indices in the T2D subjects, and the improvement was more pronounced in the carriers of the AA genotype of VDR-Cdx-2.

Keywords: Vitamin D, Adiposity, Fat mass, Visceral fat, Type 2 diabetes