Do oleic acid–enriched oil formulations improve health outcomes in metabolic disorders? A GRADE-assessed meta-analysis

Background: Oleic acid, a monounsaturated fatty acid (MUFA), exhibits beneficial properties in healthy subjects. However, it remains unclear whether these favorable effects extend to metabolically unhealthy individuals. Therefore, this study aimed to investigate the effect of an oleic acid-enriched oil formula on metabolic health outcomes. Methods: Our comprehensive systematic search was conducted in the following databases: PubMed, Scopus, Web of Science, and Google Scholar based on PRISMA guideline. The random-effect model was used to pool standardized mean differences (SMD). Results: Fifteen eligible studies met our inclusion criteria and were included in our systematic review and meta-analysis. Data analysis indicated that oleic acid consumption is not associated with improvement of lipid markers including total cholesterol (TC), low density lipoprotein cholesterol (LDL-c), high density lipoprotein cholesterol (HDL-c), and triglyceride (TG). In addition, it has been shown that subgroup analysis based on the BMI of participants, intervention duration, and oleic acid content could not modify the response to oleic acid intervention in term of lipid profile. Moreover, combined effect of studies evaluating the effect of the oleic acid on the glycemic control, obesity measures, and blood pressure illustrated that oleic acid is not potent enough to affect them in unhealthy individuals. Conclusion: The current meta-analysis indicated that oleic acid intervention exerts population specific responses; despite its beneficial properties, oleic acid does not improve health outcomes in metabolically unhealthy individuals.