Effects of Olive Leaf Polyphenols on Blood Lipid Profiles and Cardiovascular Risk Markers in Healthy and At-Risk Populations: A Narrative Review

Abstract

Background: Cardiovascular diseases and metabolic syndrome are major contributors to global morbidity and mortality. Dyslipidaemia plays a central role in their pathogenesis. Olive-derived polyphenols, particularly oleuropein and hydroxytyrosol, have gained attention for their potential lipid-modulating and vascular-protective effects. Objective: This narrative review synthesizes clinical and mechanistic evidence on the effects of olive leaf and olive oil polyphenols on blood lipid profiles and cardiovascular risk markers in both healthy and at-risk populations. Methods: Clinical studies using standardized olive leaf extracts (OLE) or olive oil preparations with defined phenolic content were included. Multi-ingredient formulations containing additional bioactive compounds were excluded to isolate the effects of olive-derived polyphenols. Evidence was categorized by population (healthy, cardiovascular risk, overweight/obese, hyperlipidaemic) and complemented by mechanistic insights from animal and cell-based studies. Results: In healthy individuals, olive derived polyphenols mainly improved oxidative and vascular markers, with little effect on absolute lipid levels. In individuals with elevated cardiovascular risk, reductions in low-density lipoprotein cholesterol, total cholesterol, triglycerides, and oxidised low-density lipoprotein were more consistently observed. Overweight and obese participants showed no lipid changes at the studied doses, while postmenopausal and mildly hyperlipidaemic adults displayed modest short term improvements and larger lipid reductions with longer supplementation. Mechanistic studies indicate that olive polyphenols influence lipid metabolism and vascular function through AMPK activation, suppression of SREBP 1c, modulation of PPAR pathways, enhancement of antioxidant defences via Nrf2 signalling, and attenuation of inflammatory pathways including NF κB and MAPK. Conclusion: Overall, current evidence indicates that olive leaf and olive oil polyphenols can beneficially modulate lipid parameters, oxidative stress, inflammation, and vascular function. The strongest and most consistent lipid related effects are observed in individuals with elevated cardiovascular risk and in long duration interventions in hyperlipidaemic postmenopausal women. While mechanistic studies support multiple pathways relevant to lipid regulation, long-term standardized clinical trials with well-characterized polyphenol compositions are needed to confirm efficacy and identify optimal dosing strategies across different metabolic phenotypes.