February 24th, 2014
Meta-Analysis Links Vegetarian Diet and Lower Blood Pressure
A new meta-analysis provides the strongest evidence yet that a vegetarian diet is strongly associated with lower blood pressure. Although various health benefits of a vegetarian diet have often been proposed, a rigorous examination of the effect on blood pressure has not been previously performed.
In a paper published in JAMA Internal Medicine, Japanese researchers analyzed data from seven clinical trials, including 311 participants, and 32 observational studies, including 21,604 participants. In the clinical trials the vegetarian diet was associated with a 4.8 mm Hg drop in the systolic blood pressure and a 2.2 mm Hg drop in the diastolic blood pressure. In the observational studies, the reductions were 6.9 mm Hg and 4.7 mm Hg.
The authors noted that the magnitude of the blood pressure-lowering effect was about half the size of typical antihypertensive drugs and roughly equivalent to commonly recommended lifestyle modifications such as a low-salt diet or weight reduction. Based on previous research the blood pressure reductions would be expected to lead to a 7% reduction in overall mortality, a 9% reduction in coronary heart disease, and a 14% reduction in stroke.
The authors speculated about possible explanations for the relationship between the vegetarian diet and blood pressure:
- Vegetarians are less likely to be obese and more likely to have a lower body mass index than nonvegetarians.
- Vegetarian diets are high in potassium.
- Some but not all studies have found that vegetarian diets contain less sodium.
- Vegetarians may drink less alcohol.