Effect of Dietary and Supplemental Lycopene on Cardiovascular Risk Factors: A Systematic Review and Meta-Analysis

ABSTRACT
Cardiovascular disease (CVD) is the leading cause of death globally and the presence of ≥1 cardiovascular risk factors elevates total risk. Lycopene, a carotenoid with high antioxidant capacity, may be protective. The aim of this systematic review and meta-analyses is to determine the efficacy of consuming dietary and/or supplemental lycopene on cardiovascular risk factors. Using the PRISMA guidelines, 4 databases were systematically searched from inception: Medline, Cinahl, Proquest, and Scopus. Intervention trials assessing dietary or supplemental lycopene on CVD outcomes were included. The Cochrane Risk-of-Bias tool was used to assess the quality of the included papers. Pooled analysis was conducted using outcomes with available data. Forty-three studies were included. Lycopene interventions were highly variable (supplement with or without food, based as tomato juice/paste/raw product, or combined with olive oil), the dose ranged from 1.44 to 75 mg lycopene/d and was not reported in 11 of 43 included studies. Studies reported conflicting findings for the effect of lycopene on cardiovascular risk factors, This was supported by meta-analyses where there were no significant differences between lycopene intervention and control groups for blood pressure and lipids (total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides). This was observed for overall groups and in subgroup analyses for individuals with elevated risk factor concentrations at baseline. Lycopene interventions for cardiovascular risk factors were highly variable across studies in both the dosage provided and the mode of delivery (supplement or food based). As such, there are conflicting findings regarding the efficacy of lycopene to improve cardiovascular risk factors. This systematic review was registered with PROSPERO as CRD42018112174.