Aim: Several studies suggest a link between vitamin D and obesity. Vitamin D may play a role in obesity. Ghrelin is an orexigenic peptide which induces obesity by central and peripheral mechanisms. Administration of ghrelin promotes food intake and decreased fat utilisation in rodents. Ghrelin levels are decreased in obese individuals.The aim of this study was to evaluate the relationship between vitamin D status and ghrelin levels.
Methods: All subjects applying to our clinic between December 2011 and February 2012 for whom 25 OH vitamin D3 (25(OH)D) levels measured were enrolled to this cross-sectional study. Those with a history of any metabolic disorder and those of any form of medication effect on obesity and vitamin D status were excluded. Patients were classified into two groups based on levels of 25(OH)D as group 1 (25(OH)D <20 ng/ml, n=65, and group 2 (25(OH)D ≥20 ng/ml, n=30.
Results: A total of 95 patients mean aged 35.06 (range, 1857) years were enrolled in the study. Age and sex were similar between groups (P>0.05). BMI and waist circumference were found significantly higher in patients with group 1 than group 2 (P<0.01). HDL-C levels were also lower in patients with group 1 than group 2 (P=0.05). Also ghrelin levels were significantly higher in patients with group 1 than group 2 (P<0.05). On the other hand a significant positive correlation was established between 25(OH)D and BMI, HDL-C (respectively r=−0.262, P=0.01 r=0.253, P=0.03). However, a similar correlation was not found for the other metabolic parameters.
Conclusion: Vitamin D deficiency effects the ghrelin levels and ghrelin might contribute to the pathogenesis of weight gain and obesity in vitamin D deficient individuals. Further prospective clinical studies are needed to establish the relationship between ghrelin and vitamin D to clarify the pathogenesis of human obesity.