Effects of tart cherry juice consumption on cardio-metabolic risk factors: A systematic review and meta-analysis of randomized-controlled trials

Background: Tart cherries are rich in bioactive compounds, such as anthocyanins and other phytochemicals known to have antioxidant properties and exert cardiovascular protective effects. However, there is no definitive consensus on this context. The present systematic review and meta-analysis aimed to investigate the effect of tart cherry juice consumption on cardio-metabolic risk factors. Methods: A systematic search was conducted on electronic databases, including PubMed, Web of Science, Scopus, and Google Scholar from inception up to December 2021 to identify eligible RCT studies. A random-effect model was utilized to estimate the weighted mean difference (WMD) and 95% confidence (95% CI). Results: Ten RCTs were included in the present meta-analysis. The pooled analysis revealed that tart cherry juice consumption led to a significant reduction in the fasting blood sugar (FBS) levels (WMD =-0.51 mg/dl [95% CI:-0.98,-0.06]). This lowering effect of FBS was robust in subgroups with cross-over studies, participants with age range >= 40, duration of follow-up <= 4 weeks, and baseline BMI >= 30. In contrast, tart cherry juice had no effect on total cholesterol (TC), triglycerides (TG), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), insulin, body mass index (BMI), fat mass, systolic and diastolic blood pressure. However, in the subgroup analysis, some significant effects were observed for insulin, TG, TC, LDL-C, and HDL-C.Conclusion: In summary, this meta-analysis showed that tart cherry juice mostly had a favorable effect on FBG levels. However, further RCTs with long-term intervention with different doses of administration are needed.