The effect of olive leaf use on blood pressure; A systematic review and meta-analysis

Abstract

Context: Hypertension has been identified as the world’s third leading cause of death. Due to their cost-effectiveness and lack of adverse effects compared to antihypertensive medications, medicinal plants have gained popularity in most countries. The olive leaf is one of these plants. As a result, the purpose of the current systematic review and meta-analysis was to determine the effect of olive leaf consumption on systolic and diastolic blood pressure. Evidence acquisition: The following domestic and international databases were searched in order to retrieve relevant studies: PubMed, Scopus, Web of Science, Embase, Cochrane, ProQuest, and Google Scholar search engine, the ClinicalTrials.gov Protocol Registration and Results System (PRS), the ISRCTN registry administered by BioMed Central, and the World Health Organization’s (WHO) International Clinical Trials Registry Platform. The data collected were analyzed using STATA software (version14) at a significance level of P<0.05. Results: Olive leaf consumption had a significant effect on systolic blood pressure [-0.87 (95% CI: -1.09, -0.64)] and diastolic blood pressure [-0.39 (95% CI: -0.57, -0.21)] in five studies with a sample size of 145 people (mean age range of 33.30 ± 5.25 years). Consumption of olive leaves also decreased cholesterol levels [-0.52 (95% CI: -0.81, -0.22)], low-density lipoprotein (LDL-c) levels [-0.35 (95% CI: -0.58, -0.12)], and triglycerides levels [-0.67 (95% CI: -1.19, -0.16)]. Nonetheless, the olive leaf had no statistically significant effect on reducing highdensity lipoprotein levels. Conclusion: We observed that olive leaf consumption significantly reduced the levels of systolic and diastolic blood pressure, cholesterol, triglycerides, and LDL-c. Registration: The current protocol was also registered on PROSPERO (ID: 221277, Date: 16.04.2022).

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“…7 Similar results were reported by Fatahian et al in a metaanalysis of five human studies (n = 145 participants), SBP and DBP being found to decrease by 0.87 and 0.39 mmHg, respectively, after olive leaf consumption. 24 In contrast, another metaanalysis found a reduction only in SBP of 11.5 mmHg after daily supplementation with 500 mg of OLE, but no significant effect on either SBP or DBP was observed after administering higher daily doses (1000 mg). 17 The possibility that OLE is more beneficial in hypertensive patients, as concluded by Razmpoosh et al, 7 indicates a mechanism of action that affects blood pressure together with other cardiovascular risk factors.…”

“…In addition, possible interactions between different bioactive compounds in the by-products have not been investigated. A further limitation, as highlighted by Razmpoosh et al and Fatahian et al, 7,24 is that most of the clinical trials covered in this review had short intervention periods, typically 4-8 weeks, which may not be sufficient to assess long-term effects on cardiometabolic and inflammatory markers, especially in healthy subjects.…”

“…Similar results were reported by Fatahian et al . in a meta‐analysis of five human studies ( n = 145 participants), SBP and DBP being found to decrease by 0.87 and 0.39 mmHg, respectively, after olive leaf consumption 24 . In contrast, another meta‐analysis found a reduction only in SBP of 11.5 mmHg after daily supplementation with 500 mg of OLE, but no significant effect on either SBP or DBP was observed after administering higher daily doses (1000 mg) 17 .…”

“…A further limitation, as highlighted by Razmpoosh et al . and Fatahian et al ., 7,24 is that most of the clinical trials covered in this review had short intervention periods, typically 4–8 weeks, which may not be sufficient to assess long‐term effects on cardiometabolic and inflammatory markers, especially in healthy subjects. Nor did most studies consider potential confounding variables such as body mass index (BMI), dietary intake, physical activity, alcohol consumption, and smoking.…”