Consumption of vitamin D-fortified yogurt drink increased leptin and ghrelin levels but reduced leptin to ghrelin ratio in type 2 diabetes patients: a single blind randomized controlled trial.

PURPOSE: This study aimed to evaluate the effect of daily consumption of vitamin D-fortified yogurt drink (doogh) in comparison with plain doogh on appetite-regulating hormones including leptin and ghrelin in type 2 diabetes (T2D) patients.

METHODS: In a single blind randomized clinical trial, subjects with T2D were randomly allocated to one of the two groups and received either vitamin D3-fortified doogh (FD; containing 170 mg calcium and 500 IU/250 mL, n 2  = 50) or plain doogh (PD; containing 170 mg calcium and no vitamin D/250 mL, n 1  = 50) twice a day for 12 weeks. Leptin and ghrelin were evaluated at the beginning and after 12 weeks of intervention.

RESULTS: The intervention resulted in a significant improvement of circulating 25(OH)D, fasting glucose, Quantitative Insulin Check Index (QUICKI), hs-CRP, in FD compared with PD group. A significant rise in both serum leptin (+1.3 ± 7.2 mg/L; p = 0.013) and ghrelin (10.1 ± 26.1 ng/L; p = 0.012) was observed in FD group. A between-group difference for ghrelin changes (p = 0.029) remained significant after adjusting for changes QUICKI (p = 0.039), body mass index (p = 0.034) and hs-CRP (p = 0.022). Despite an increase in both leptin and ghrelin, leptin to ghrelin (L/G) ratio actually decreased in FD. Changes of L/G ratio showed a significant between-group difference (p = 0.036), which remained significant even after adjusting for changes of hs-CRP (p = 0.028) and fat mass (p = 0.047) but disappeared after adjusting for changes of QUICKI (p = 0.42).

CONCLUSIONS: Daily intake of vitamin D-fortified doogh may increase circulating leptin and ghrelin but L/G ratio may actually decrease. Our results suggest that improving vitamin D may result in an improvement in insulin sensitivity which may finally regulate beneficially appetite hormones. Further studies with adequate power are needed to confirm the results.