Efficacy and safety of oral and inhalation commercial beta-glucan products: Systematic review of randomized controlled trials

Background & aims: Beta-glucans are advertised as biologically active compounds, with various health claims. We aimed to summarize results about efficacy and safety of commercial oral and inhalation betaglucan products on human health from randomized controlled trials (RCTs). Methods: We conducted systematic review of RCTs. We searched MEDLINE, CENTRAL and ClinicalTrials.gov . Any commercial product, any types of participants and any health-related outcomes were eligible. Two authors independently screened studies and extracted data. Cochrane risk of bias tool was used. This review did not have any extramural funding. Registration: PROSPERO record no. 42016043539. Results: We included 30 RCTs that were conducted on healthy or ill participants. Most of the trials reported beneficial effect of beta-glucan, but among the 105 different outcome domains and measures that were used, only three could be considered clinically relevant, while others were various biomarkers and surrogate outcomes such as complete blood count. Included studies on average had 33 participants per study arm, high or unclear risk of bias of at least one domain, and only half of them reported data for safety. More than half of trials that reported source of funding indicated commercial sponsorship from producers of beta-glucan. Only five RCTs reported trial registration. Conclusions: Commercial beta-glucan products were studied in a number of RCTs whose results can be considered only as preliminary, as they used small number of participants and surrogate outcomes. The quality of many studies was poor and further research and trials on bigger population should be performed before a final conclusion can be made. (C) 2019 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.