The effect of phytochemicals in prediabetic patients: A systematic review of randomized controlled trials

This study aimed to perform a systematic review to evaluate the effect of phytochemical consumption on the cardiometabolic parameters of prediabetic patients. A comprehensive search was conducted in PubMed, Scopus and ISI Web of Science, and Google Scholar up to June 2022 to find randomized controlled trials investigating the effects of phytochemicals alone or in combination with other nutraceuticals on prediabetic patients. Twenty-three studies with 31 treatment arms comprising 2177 individuals were included in this study. Totally, in 21 arms, phytochemicals had positive effects on at least one measured cardiometabolic factor. In 13 out of 25 arms, fasting blood glucose (FBG) and in 10 out of 22 arms, hemoglobin A1c (HbA1c) significantly decreased compared with the control group. Furthermore, phytochemicals had beneficial effects on 2-h postprandial and postprandial glucose, serum insulin, insulin sensitivity, and insulin resistance as well as inflammatory factors including high-sensitivity C-reactive protein (hs-CRP), tumor necrosis factor alpha (TNF-alpha), and interleukin 6 (IL-6). Triglyceride (TG) was the abundant improved factor in the lipid profile. However, no sufficient evidence for notable positive effects of phytochemicals on blood pressure and anthropometry indices was observed. Phytochemical supplementation may have beneficial impacts on prediabetic patients by ameliorating glycemic status.