A Systematic Review and Meta-Analysis to Evaluate the Effects of Chitosan on Obesity Indicators.

Chitosan, a commonly used dietary supplement, is believed to have the potential to decrease body weight by binding to dietary fats and decreasing their absorption. However, due to conflicting results from various studies, this review aimed to investigate the effects of chitosan supplementation on obesity indicators in adults. To find appropriate randomized clinical trials (RCTs), a thorough search was conducted across electronic databases like PubMed/Medline, Scopus, and ISI Web of Science. The random-effects method was employed to combine the data, and the outcomes were presented as the weighted mean difference (WMD) with 95% confidence intervals (CIs). In total, 19 RCTs with 21 effect sizes were included in the meta-analysis. The combined analysis showed that chitosan supplementation significantly reduced body weight (WMD = -0.79 kg; 95% CI, -1.30 to -0.29;  = 0.002) and body-fat percentage (BFP) (WMD = -0.41%; 95% CI, -0.50 to -0.32;  < 0.001). Additionally, there was a notable increase in fat-free mass (FFM) (WMD = 0.20 kg; 95% CI, 0.06-0.34;  = 0.005). However, no significant impact of chitosan on body mass index (BMI) (WMD = -0.35 kg/m, 95% CI: -0.71, 0.00;  = 0.054) and waist circumference (WC) (WMD = -0.71 cm, 95% CI: -1.49, 0.05;  = 0.069) was observed. Overall, chitosan supplementation shows promise in improving obesity indicators by reducing BFP and increasing FFM. However, further well-designed studies with larger sample sizes are needed to confirm these findings.