The Effect of Herbal Supplements on Blood Pressure: Systematic Review and Meta-Analysis

Herbal supplements rich in phenolic compounds are evidenced to have a protective effect against cardiovascular diseases. Therefore, they are suggested to be included in diets for people with hypertension (HT). HT is a global health problem and is estimated to affect billions of people until the end of 2025. For this reason, every possible and effective solution preventing HT should be considered. The aim was to perform an updated meta-analysis and review of recently published studies to evaluate the effect of selected herbal supplements on blood pressure reduction. We searched the PubMed database with specified selection criteria, analysing the RCT studies from 2011 to 2021. A total of 31 studies were included in the analysis, and the meta-analysis was conducted on the data from 16 of them. The general effect size of all the supplements via placebo was d = 1.45, p < 0.05 for systolic blood pressure (SBP) and d = 0.31, p < 0.05 for diastolic blood pressure (DBP). The meta-analysis and review of the literature demonstrated that herbal supplements, such as resveratrol, cherry juice, beetroot juice, bergamot extracts, barberry, and pycnogenol, can be effective in blood pressure reduction and cardiovascular prevention, but attention should be paid to their appropriate dosage due to the possibility of side effects from the digestive system.