Effect of tomato consumption on fasting blood glucose and lipid profiles: A systematic review and meta-analysis of randomized controlled trials

Tomato (Solanum lycopersicum) phytochemicals, which include phytoene, phytofluene, beta-carotene, flavonoids, lycopene, and polyphenols, have been shown to improve the effects of fasting on plasma triglyceride (TG), low-density lipoprotein cholesterol (LDL), high-density lipoprotein cholesterol (HDL), total cholesterol (TC), and fasting blood sugar (FBS). The aim of this study was to systematically evaluate the effects of Tomato TC, TG, HDL, LDL, and FBS in humans. A systematic literature search was conducted in PubMed/MEDLINE, Web of sciences, and SCOPUS databases by two researchers for studies published until August of 2019 without language and time limitations. Results were combined with random effect models. Six studies were included in this meta-analysis. Combined results reveal a significant reduction in cholesterol (weighted mean difference [WMD]: -4.39 mg/dl, 95% CI: -7.09, -1.68, I-2 = % 48, p heterogeneity: .05), TG (WMD: -3.94 mg/dl, 95% CI: -7.67, -0.21, I-2 = % 90, p heterogeneity: .001), LDL levels (WMD: -2.09 mg/dl, 95% CI: -3.73, -0.81, I-2 = % 78, p heterogeneity: .001), and increasing in HDL levels (WMD: 2.25 mg/dl, 95% CI: 0.41, 4.10, I-2 = % 97, p heterogeneity: .001). Tomato was found to have a higher reduction effect on TG and LDL in younger participants. While pooled results indicate no significant effect on FBS levels (WMD: 0.59 mg/dl, 95% CI: -0.28, 1.46, I-2 = % 95, p heterogeneity: .001). In conclusion, the results indicate a significant reduction in total cholesterol, TG, and LDL and increase in HDL levels that is caused by tomato consumption.