Lancet. 1983 Jan; 1(8314-5): 5-10.

Blood-pressure-lowering effect of a vegetarian diet: controlled trial in normotensive subjects.

Rouse IL, Beilin LJ, Armstrong BK, Vandongen R.

59 healthy, omnivorous subjects aged 25-63 years were randomly allocated to a control group, which ate an omnivorous diet for 14 weeks, or to one of two experimental groups, whose members ate an omnivorous diet for the first 2 weeks and a lacto-ovo-vegetarian diet for one of two 6-week experimental periods. Mean systolic and diastolic blood pressures did not change in the control group but fell significantly in both experimental groups during the vegetarian diet and rose significantly in the experimental group which reverted to the omnivorous diet. Adjustment of the blood-pressure changes for age, obesity, heart rate, weight change, and blood pressure before dietary change indicated a diet-related fall of some 5-6 mm Hg systolic and 2-3 mm Hg diastolic. Although the nutrient(s) causing these blood-pressure changes are unknown, the effects were apparently not mediated by changes in sodium or potassium intake.