Effects of Vegetarian Diets on Blood Pressure Lowering: A Systematic Review with Meta-Analysis and Trial Sequential Analysis.

Kai Wei Lee, Hong Chuan Loh, Siew Mooi Ching, Navin Kumar Devaraj, Fan Kee Hoo

Journal: Nutrients 2021;12(6):1604

PMID: 32486102

Plain Language Summary

High blood pressure or hypertension is defined as systolic blood pressure of 140 mmHg or higher, and diastolic blood pressure of 90 mmHg or higher. It is an independent and major risk factor for cardiovascular disease and chronic kidney failure. The aim of this study was to determine the effect of a vegetarian diet on the reduction of blood pressure. This study is a systematic review together with trial sequential analysis. A total of 15 studies involving 856 individuals met the eligibility criteria and were included in the final analyses. Results show that a vegetarian dietary pattern significantly reduced systolic and diastolic blood pressure. Furthermore, dietary patterns based solely on plant sources are more effective in reducing blood pressure than other types of vegetarian diet which still include animal products or by-products, such as eggs and dairy products. Authors conclude that vegetarian diets, especially vegan diets, reduce blood pressure when compared with omnivorous diets. Thus, suggesting that they may be crucial in the primary prevention and overall management of hypertension.

Abstract

The beneficial effects of a vegetarian diet on blood pressure (BP) control have been reported in previous systematic reviews; however, so far, their relative effectiveness is not well established. Here, we performed a systematic review together with trial sequential analysis to determine the effect of a vegetarian diet on the reduction of blood pressure. We searched the randomized controlled trial (RCT) through Medline, PubMed and Cochrane Central Register. Fifteen eligible RCTs with 856 subjects were entered into the analysis. The pooled results demonstrated that vegetarian diet consumption significantly lowered the systolic blood pressure (weighted mean difference (WMD), -2.66 mmHg (95% confidence interval (CI) = -3.76, -1.55, < 0.001) and diastolic BP was WMD, -1.69 95% CI = -2.97, -0.41, < 0.001) as compared to an omnivorous diet. In subgroup analysis, a vegan diet demonstrated a greater reduction in systolic BP (WMD, -3.12 mm Hg; 95% CI = -4.54, -1.70, < 0.001) as compared with a lacto-ovo-vegetarian diet (WMD, -1.75 mm Hg, 95% CI -5.38, 1.88, = 0.05). The vegan diet has showed a similar trend in terms of diastolic blood pressure reduction (WMD, -1.92 mm Hg (95% CI = -3.18, -0.66, < 0.001) but those with a lacto-ovo-vegetarian diet showed no changes in diastolic BP reduction (WMD, 0.00, 95% CI = 0.00, 0.00), =0.432). In conclusion, vegetarian diets are associated with significant reductions in BP compared with omnivorous diets, suggesting that they may play a key role in the primary prevention and overall management of hypertension.

Address: Department of Family Medicine, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia.; Clinical Research Centre, Hospital Seberang Jaya, Ministry of Health Malaysia, Perai 13700, Penang, Malaysia.; Department of Family Medicine, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia.; Malaysian Research Institute on Ageing, University Putra Malaysia, Serdang 43400, Selangor, Malaysia.; Department of Medical Sciences, School of Healthcare and Medical Sciences, Sunway University, Bandar Sunway 47500, Selangor, Malaysia.; Department of Family Medicine, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia.; Malaysian Research Institute on Ageing, University Putra Malaysia, Serdang 43400, Selangor, Malaysia.; Department of Medicine, Faculty of Medicine and Health Sciences, University Putra Malaysia, Serdang 43400, Selangor, Malaysia.

DOI: 10.3390/nu12061604