The Effect of Vegan Diets on Blood Pressure in Adults: A Meta-Analysis of Randomized Controlled Trials

Vegan diets are increasing in popularity and have beneficial effects on glycemia and blood lipids, but the evidence is inconclusive regarding their effect on blood pressure. The purpose of this study was to review the effect of vegan diets on blood pressure in adults. We searched MEDLINE, EMBASE, CENTRAL, and ClinicalTrials.gov for records that compared a vegan diet with any less restrictive diet and reported pre- and postintervention systolic and diastolic blood pressures. Two reviewers independently screened abstracts for randomized, controlled clinical trials in individuals ≥18 years of age and older. We used the PRISMA guidelines to select 11 clinical trials from 1673 records. Data synthesis was performed through a random-effects model. The pooled data included 983 participants. Compared with less restrictive diets, a vegan diet did not result in a significant change in systolic (−1.33 mm Hg; 95% confidence interval [CI], −3.50-0.84; P = .230) or diastolic (−1.21 mm Hg; 95% CI, −3.06-0.65; P = .203) blood pressure. A prespecified subgroup analysis of studies with baseline systolic blood pressure ≥130 mm Hg revealed that a vegan diet resulted in a mean decrease in the systolic (−4.10 mm Hg; 95% CI, −8.14 to −0.06; P = .047) and diastolic (−4.01 mm Hg; 95% CI, −5.97 to −2.05; P = 0.000) blood pressures. The changes in blood pressure induced by a vegan diet without caloric restrictions are comparable with those induced by dietary approaches recommended by medical societies and portion-controlled diets.