Vitamin D deficiency or insufficiency is common in obese people, with some studies suggesting that low vitamin D level might be an independent predictor of obesity. Thus, the purpose of the present randomized, double-blind, placebo-controlled study was to investigate the effect of oral spray vitamin D₃ 3000 IU supplementation along with personalized weight-loss diet on obesity markers in overweight and obese Caucasians with vitamin d deficiency or insufficiency. The impact of vitamin D receptor (VDR) and adrenergic receptors (ADRs) genetic variants on vitamin D levels and weight loss diet outcomes was also investigated. After signing informed consent, a total of 125 eligible volunteers were randomly assigned into vitamin D (vitamin D₃ 3000 IU/d oral spray supplementation, n = 76) or placebo (xylitol, water, mint, n = 49) group following a weight loss program (600 calories less than the total energy expenditure of each volunteer) for 3 months. Fat mass, BMI, REE and 25(OH)D serum level were monitored on baseline and each month. DNA samples were extracted from buccal swabs and genotyped for the rs2228570 (VDR), rs1544410 (VDR), rs731236 (VDR), rs1800544 (ADRA2A), rs1801252 (ADRB1), rs1042713 (ADRB2), and rs4994 (ADRB3) polymorphisms. Statistical analysis was performed using SPSS package (v.23). Between group comparisons revealed significant improvement in serum 25(OH)D level and greater reduction in weight, BMI and fat percentage in the vitamin D group compared to placebo group (p < 0.05). In the vitamin D group, carriers of the rs2228570 T allele tended to have greater vitamin D level improvement compared with the homozygous C allele (p = 0.067). Furthermore, heterozygous (CT) for the rs731236 tended to have lesser weight loss (p = 0.068) and for the rs1042713, a lower decline in fat percentage was observed for homozygous AA carriers compared to the heterozygous (p = 0.051). In the control group, differences in weight loss (p = 0.055) and BMI (p = 0.045) were observed between rs1544410 AA and GG homozygous. In conclusion, vitamin D oral spray supplementation seems to improve vitamin D status and decrease obesity markers during a weight-loss intervention in overweight/obese Caucasians with vitamin D deficiency or insufficiency. Also, the results of the present study indicate that VDR and ADRs genetic polymorphisms seem to influence vitamin D supplementation response and obesity markers.

Objectives: To evaluate the efficacy of a fixed-dose combination of berberine, white mulberry leaf extract, and chromium picolinate on body weight, body composition, and insulin sensitivity in Greek adults with obesity. Research Methodology/Design: This was a 12-week, randomized, double-blind, placebo-controlled trial. Adults with obesity and no diagnosed chronic disease were randomly assigned to receive either berberine (1000 milligrams), white mulberry leaf extract (400 milligrams standardized to 5% 1-deoxynojirimycin), and chromium picolinate (0.644 milligrams) or a matching placebo, administered in two daily doses before the main meals. Setting: The study was conducted in Greece among community-dwelling adults with obesity. Main Outcome Measures: The primary outcome was insulin sensitivity, assessed using the Matsuda Composite Insulin Sensitivity Index derived from a 75-g oral glucose tolerance test. Secondary outcomes included body mass index, total body fat mass, and visceral fat rating. Results: Ninety-three participants were randomized, with 46 assigned to the active intervention and 47 to placebo. Compared with placebo, the active intervention produced significantly greater reductions in body mass index (adjusted mean difference −1.24 kg per square meter; 95% confidence interval −2.15 to −0.33), total body fat mass (−2.35 kg; 95% confidence interval −4.12 to −0.58), and visceral fat rating (−0.92 units; 95% confidence interval −1.74 to −0.10). Insulin sensitivity improved significantly, with a 28% greater improvement in the active group than in the placebo group (adjusted geometric mean ratio 1.28; 95% confidence interval 1.14 to 1.44). Conclusions: The fixed-dose combination improved BIA-derived body-composition measures and OGTT-derived insulin sensitivity over 12 weeks compared with placebo. Because no single-agent arms were included, individual component contributions and synergy remain undetermined; confirmatory trials using direct metabolic and imaging methods are warranted.