Inositol supplementation and body mass index: A systematic review and meta-analysis of randomized clinical trials

Background Inositol is a sugar-alcohol and recognized as a key component of cell membrane phospholipids. It has crucial role in the cell signaling pathways and contribute to improving glycemic responses. Although some earlier studies have revealed the effect of inositol mediating glucose uptake by improving insulin sensitivity, the benefit of inositol supplementation in patients with overweight and obesity is not completely understood. This study aimed to assess the impact of inositol supplementation on body mass index (BMI) through a systematic review and meta-analysis of controlled clinical trials. Methods A systematic search was performed to August 2021 in the following databases: PubMed-Medline, Embase, Web of Science and Scopus. Fifteen controlled clinical trials investigating the effect of inositol on adult's BMI were finally included in the study. A random-effects model was employed to estimate the effect size. Subgroup analysis was performed by dose, duration, age, type of inositol. Meta-regression was used to investigate presence of any linear relationship. Begg's and Egger's tests were carried out to detect small study effect. Results The results of pooled analysis showed that inositol supplementation significantly decreased BMI scores (WMD = -0.41 kg/m(2); 95% CI: -0.78, -0.04; p = 0.028). Subgroup analysis was performed to identify the source of heterogeneity among studies (I-2 = 73.9%, p < 0.001), demonstrating supplementation duration, baseline BMI, mean age of participants, type of inositol and dosage were potential sources of heterogeneity. The effect of intervention was more clinically significant in participants with polycystic ovary syndrome (PCOS) and overweight/obesity. Inositol in the form of myo-inositol (MI) had stronger effect on BMI reduction. Conclusion The meta-analysis suggests that oral inositol supplementation has positive effect on BMI reduction. Inositol supplementation could be considered as an adjunct treatment to improve body mass index.