What are the effects of N-acetylcysteine supplementation on anthropometric indices? A systematic review and meta-analysis of clinical trials

Abstract Background N-acetyl cystatin (NAC) potentially can contribute to weight changes due to its antioxidant activities. Aim of the review we carried out a systematic review and meta-analysis of randomized clinical trials in order to examine whether NAC consumption can result in any changes in anthropometric indices. Methods Using appropriate keywords, we searched online databases of PubMed-Medline, SCOPUS, Web of Science, Embase databases and Google Scholar, published for relevant articles up to Nov 2019. Random-effect model was employed to report weighted mean differences. Sensitivity and subgroup analyses were carried out. Results A number of 7 eligible studies were identified. The results indicated no significant effect of NAC on BMI, weight and WC [(SMD=-0.08 Kg/m2 ; CI: -0.25, 0.08; P = 0.335, I2 = 0.0 %, P = 0.967), (SMD= -0.38 Kg; 95 % CI: -2.11, 2.87; P = 0.766, I2 = 0.0 %, P = 0.691) and (SMD= -0.22 Cm; 95 % CI: 0.52, 0.08; p = 0.153, I2 = 0.0 %, P = 0.826), respectively. No effect of sensitivity and subgroup analyses were observed. Conclusion There was no significant effect of NAC supplementation on obesity indices. As far as we assessed anthropometric factors mainly as the secondary outcome in these studies rather than the main outcome, more specific trials are suggested to assess this relationship precisely.