Vitamin D supplementation decreases visceral adiposity and normalizes leptinemia and circulating TNF-α levels in western diet-fed obese rats.

Aims: Vitamin (Vit) D regulates various organic processes, including adipose tissue morphofunction and lipid metabolism. Studies indicate that Vit D bioavailability is reduced in obesity, which could contribute to obesity development; however, the effects of Vit D supplementation on increased adiposity in western diet (WD)-obese rats (an experimental model that better resembles the obesogenic human obesity condition) have not been studied, to date. Thus, we hypothesized that Vit D supplementation following the induction of obesity in WD rats might reduce their body weight (BW) and adiposity.

Main Methods: Male Wistar rats were fed on a standard chow [control (CTL) group] or a WD to induce obesity (WD group), from 21 to 59 days of age. Subsequently, from 60 to 90-days, half of the CTL and of the WD rats were randomly submitted, or not, to oral Vit D supplementation (CTL-VD and WD-VD groups, respectively).

Key Findings: At 91 days of age, WD rats were obese, displaying higher abdominal circumference and white fat stores, dyslipidemia, hyperleptinemia and greater plasma levels of tumor necrosis factor (TNF)-α. Vit D supplementation decreased BW gain, abdominal fat deposition and ameliorated the plasma lipid profile in WD-VD rats. These effects were accompanied by reductions in leptinemia and in circulating TNF-α levels in these rodents.

Significance: Vit D supplementation, following the induction of obesity, may represent a good strategy to attenuate BW gain and abdominal adiposity, and ameliorate the plasma lipid profile in WD rats. These effects may be mediated, at least in part, by reductions in circulating levels of leptin and TNF-α.