Diets rich in oleic acid have been proposed as a strategy to modify cardiometabolic risk. Evidence from randomized controlled trials (RCTs) remains inconsistent, particularly for glucose-related outcomes. To assess the effects of high-oleic dietary interventions compared with lower-oleic diets on lipid profiles, and glycemic indices in adults. PubMed, Embase, Web of Science, and Scopus were searched from inception to July 2025 in accordance with PRISMA 2020 guidelines. RCTs were eligible if the intervention diet provided at least 70% of total fatty acids as oleic acid, justified based on prior monounsaturated fat intervention literature, and differed from the comparator by at least 5% points. Random-effects meta-analyses were performed using weighted mean differences. Certainty of evidence was evaluated using the GRADE framework with outcome-specific assessments reported in a Summary of Findings table. Twenty-six trials involving 1,244 participants were included. High-oleic diets were associated with modest reductions in total cholesterol (WMD: -0.14; 95% CI: -0.28 to -0.01; I2 = 80.8%), and LDL-C (WMD: -0.13; 95% CI: -0.24 to -0.03; I2 = 64.6%). No significant effects were observed for HDL-C, triglycerides, fasting blood glucose, fasting insulin, or HOMA-IR. Lipid-lowering effects were more evident in trials with higher oleic acid proportions (≥ 80%). High-oleic dietary interventions result in small but consistent improvements in selected lipid outcomes without effects on glycemic indices. Benefits are dose-dependent and most pronounced when oleic acid constitutes a substantial portion of dietary fat. Absolute changes are modest, highlighting the complementary role of high-oleic diets in cardiometabolic risk management.
Han et al. (2026) studied this question.