The impact of oleuropein, hydroxytyrosol, and tyrosol on cardiometabolic risk factors: a meta-analysis of randomized controlled trials

The so-called Mediterranean diet, with olive oil as a key component, is effective in reducing cardiometabolic disease risk. Olive oil consumption improves blood pressure, insulin levels and resistance, supporting heart health and glycemic control. Its phenolic compounds, including oleuropein (OLE), hydroxytyrosol (HT), and tyrosol (TYR) are hypothesized to likely contribute to these benefits. Thus, this meta-analysis evaluated the clinical effects of dietary supplementation with OLE, HT, and TYR on cardiometabolic outcomes. Fourteen human intervention studies with 594 participants were included. The analysis using a random-effects model showed that OLE, HT, and TYR significantly reduced total cholesterol (SMD = −0.19, CI: −0.37 to −0.01, p = 0.04, I2 = 35%), triacylglycerol (SMD = −0.32, CI: −0.60 to −0.03, p = 0.03, I2 = 73%), and insulin (SMD = −0.42, CI: −0.82 to −0.01, p = 0.04, I2 = 78%). Subgroup analysis showed that, in certain contexts, interventions may be more beneficial for BMI <30, non-Mediterranean, and cardiometabolic disease individuals, while intervention compound, type of intervention, and duration might have differential effects regarding considered outcomes. Overall, the meta-analysis suggests that supplementation with OLE, HT, and TYR may beneficially impact some cardiometabolic parameters, though further studies are needed to confirm these findings.