Vitamin D reduces high-fat diet induced weight gain and C-reactive protein, increases interleukin-10, and reduces CD86 and caspase-3.

Obesity can be associated with dysfunction of the immune system. An increased risk of obesity has been reported among individuals with low levels of vitamin D. However, much is still unknown about the link between vitamin D and dysfunction of the spleen and immune system in obesity. Therefore, the objectives of this study were to evaluate the effects of a high-fat diet (HFD) on the spleen and immune system and to determine the protective effects of chronic treatment with vitamin D in reversing the detrimental effects of HFD. Body weight (BW) gain, the serum levels of calcium, C-reactive protein (CRP), and interleukin-10 (IL-10), and the expression of both CD86 and caspase-3 in the spleen were investigated. Twenty-four adult male Wistar rats were divided into three equal groups: the control (C) group received a control diet for 10 weeks, the HFD-C group received a HFD for 10 weeks, and the HFD-treated group received a HFD co-administered with oral vitamin D (1μg/kg) daily for 10 weeks. Administration of vitamin D in combination with HFD significantly decreased BW gain, decreased the serum levels of both calcium and CRP, increased the serum level of IL-10, improved the general histological appearance of the spleen, and decreased the expression of both CD86 and caspase-3 in the spleen in comparison with results seen in the HFD-C group. Our data suggest that vitamin D supplementation holds promise as an adjunct treatment to alleviate the dysfunction of the spleen and immune system commonly seen in HFD-induced obesity.