Olive leaf extract effect on cardiometabolic risk factors: a systematic review and meta-analysis of randomized clinical trials

Abstract

Context Olive leaf extract (OLE) is rich in phenolic compounds, which are known for their health benefits. Cardiovascular diseases, primarily coronary heart disease and stroke, are leading causes of mortality globally. Objective This systematic review aimed to assess the impact of OLE on cardiometabolic risk factors in adults. The selection of studies was based on intervention and outcomes, using relevant search descriptors. Data Sources The databases PubMed, EMBASE, and Web of Science were systematically searched for pertinent studies published up to August 2021. Data Extraction Only randomized clinical trials, either cross-over or parallel, involving adult individuals aged ≥18 years, were considered. Additionally, trials that had a comparative or placebo group and used pure OLEs for oral treatment were included. Data Analysis Twelve randomized clinical trials (RCTs) met the inclusion criteria. These trials had follow-up periods ranging from 2 days to 12 weeks and involved 703 patients aged 18 years–79 years. The outcomes demonstrated a positive correlation between the intervention group and glucose metabolism (4 RCTs), blood pressure (2 RCTs), lipid profile (2 RCTs), and inflammatory markers (2 RCTs). The RoB2 tool and the GRADE system were used to evaluate the risk of bias and the quality of evidence in the studies. Conclusions In the meta-analysis, fasting glycemia, as evaluated in studies using a low dose of OLE, showed a significant result favoring the control group. To obtain more consistent results, further clinical studies in humans, using similar methodologies, are required. Systematic Review Registration PROSPERO registration no. CRD42020200877.

Safety classification of herbal medicine use among hypertensive patients: a systematic review and meta-analysis

“…The mechanism of action of O. europaea involves ACE inhibition, Ca 2+ channel blockade, vasodilation, and antioxidant effects of flavonoids such as quercetin and rutin. Clinical trials administering 500 mg/day of O. europaea leaf extract versus placebo or no treatment resulted in a significant reduction in systolic/diastolic BP of 11.5/4.8 mmHg over 8 weeks (EKİCİ et al, 2023;Álvares et al, 2024). The beneficial effects of 900 mg/day C. oxyacantha on HTN have been consistently reported, where significant reductions in both SBP and DBP of approximately 17.2 mmHg and 9.2 mmHg, respectively, have been observed, especially when used for at least 12 weeks.…”

Potential Therapeutic Properties of Olea europaea Leaves from Selected Cultivars Based on Their Mineral and Organic Profiles

“…Lately, olive leaves have become part of many diets in the form of an extract or as a whole herbal powder [ 16 , 17 , 18 ]. Olive leaves’ biological compounds yield cardiovascular-protective properties [ 19 ]. Not only do numerous studies confirm that olive leaves are able to decline blood pressure, improve blood flow in the coronary arteries [ 20 , 21 ], regulate arrhythmia, and prevent intestinal smooth muscle spasms [ 22 ], but their antimicrobial potential against bacteria, fungi, and mycoplasma has also been highlighted [ 23 , 24 , 25 , 26 , 27 ].…”