Is Vitamin D Supplementation Useful for Weight Loss Programs? A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

The controversy about the impact of vitamin D supplementation on weight loss treatment was observed in several randomized controlled trials (RCTs). This meta-analysis investigates the effects of vitamin D supplementation (cholecalciferol or ergocalciferol) on weight loss through holistic measurements of Body Mass Index (BMI), weight and waist circumference. Google Scholar, WOS, PubMed and Scopus were explored to collect relevant studies. The selected articles focused on vitamin D supplementation in overweight and obese individuals with different conditions. Eleven RCTs were included into this meta-analysis with a total of 947 subjects, with a mean of the follow-up from 1 to 12 months and different vitamin D interventions (from 25,000 to 600,000 IU/monthly of cholecalciferol). The meta-analyzed mean differences for random effects showed that cholecalciferol supplementation deceases the BMI by -0.32 kg/m (CI95% -0.52, -0.12 kg/m, = 0.002) and the waist circumference by -1.42 cm (CI95% -2.41, -0.42 cm, = 0.005), but does not statistically affect weight loss -0.43 kg (CI95% -1.05, +0.19 kg, = 0.17). This meta-analysis lays the foundation for defining the potential clinical efficacy of vitamin D supplementation as a potential therapeutic option for weight loss programs, but further studies are needed to confirm the validity of these findings and delineate potential underlying mechanisms.