Lower blood pressure may be one dividend of an all-vegetarian diet, according to a recent meta-analysis.
A plethora of lifestyle choices and dietary recommendations, including the DASH diet and more recently, the Mediterranean diet, have been shown to improve cardiovascular outcomes. In a recent study published in JAMA Internal Medicine, Yokoyama et al, examined whether consuming an all-vegetarian diet could alter blood pressure (BP) control.
This study comprised a meta-analysis of 32 observational studies (N=21,604) and 7 clinical trials (N=311) that met prespecified inclusion criteria (subjects >20 years of age, vegetarian diet was the intervention and BP was an outcome). The primary outcome was the net difference in both systolic and diastolic BP. The mean age of participants was approximately 47 years, reflecting a relatively young population. Not surprisingly, a vegetarian diet was associated with an approximate 5 to 7 mm Hg reduction in mean systolic BP and an approximate 2 to 5 mm Hg reduction in mean diastolic BP compared with a normal diet.
The strengths of this study are a very large sample size, even though most of the sample population is derived from observational studies. Because of this, there may be residual confounding in the observational dataset whereby those patients who consumed a vegetarian diet also adopted other comparatively healthy lifestyle behaviors. Although the BP reductions were somewhat modest and the mean age of the participants reflected a younger population, the take-home message of this study is consistent with previous studies: eliminating meat and consuming a diet rich in fruits and vegetables offers many health benefits, including lower BP.
Your patients with hypertension or pre-hypertension would benefit from knowing these results; the study could be used to start a conversation about the benefits of this non-pharmacologic intervention that may be relatively simple to apply.
Yokoyama Y, Nishimura K, Barnard ND, et al. Vegetarian diets and blood pressure: a meta-analysis. JAMA Intern Med. 2014;174:577-587. doi:10.1001/jamainternmed.2013.14547.