Vitamin D Supplementation and Its Relationship with Loss of Visceral Adiposity

An inverse relationship between vitamin D (VD) nutritional status and obesity is frequent, and the distribution of body fat is an important aspect to assess the risks of obesity-related metabolic dysfunction. The purpose of the study was to evaluate the relationship between serum VD concentrations and body fat reduction after 12 months of bariatric surgery, using two different vitamin D3 (VD3) supplementation protocols.

A randomized controlled trial consisted of 41 patients divided into G1 (800 IU/day) and G2 (1800 IU/day) according to the VD3 supplementation. At baseline (T0) and follow-up (T1), 25(OH)D, waist circumference (WC), visceral adiposity index (VAI), body adiposity index (BAI), and waist/height ratio (WHtR) were evaluated.

In T0, the mean of 25(OH)D was lower in G2 compared to that in G1 (22.6 vs 23.6 ng/mL; p = 0.000). At T1, it had a significant increase in G2 (32.1 vs 29.9 ng/mL; p = 0.000), with 60% sufficiency. A significant negative correlation was observed between VAI, BAI, and WHtR with 25(OH)D in G2 (r =  - 0.746, p = 0.024; r =  - 0.411, p = 0.036; r =  - 0.441, p = 0.032) after surgery. Higher mean changes from baseline of visceral fat loss, represented by VAI, were observed in G2 (176.2 ± 149.0-75.5 ± 55.0, p = 0.000).

Patients submitted to the 1800 IU/day protocol, 12 months after the surgical procedure, had a higher percentage of sufficient vitamin D levels compared to those submitted to the 800 IU/day protocol. Additionally, higher dose supplementation promoted a significant improvement in VAI.