Urinary sodium and blood pressure in vegetarians

Abstract

Urinary sodium, potassium, urea, creatinine, uric acid, plasma urea, creatinine, cholesterol, blood pressures, height, weight, and skinfold thickness were measured in some or all of 106 matched pairs of vegetarians (mainly Seventh-Day Adventists) and nonvegetarians. Mean blood pressures were lower in vegetarians (141.9/88.9 mm) than nonvegetarians (148.0/90.9 mm) but the urinary excretion of sodium was higher, although not significantly, in the vegetarians (mean of 169.7 compared with 161.2 mmole/day). The vegetarians also had a higher urinary potassium excretion (62.9 mmole/day) than the nonvegetarians (54.8 mmole/day) thus giving them a lower mean sodium to potassium ratio (3.0 compared with 3.3). Both systolic and diastolic blood pressures correlated positively with plasma cholesterol levels which were less in vegetarians (6.0 mmole/liter) than nonvegetarians (6.6 mmole/liter). They also correlated positively with the urinary sodium to potassium ratio, but only in nonvegetarians. It was concluded that dietary sodium does not explain the blood pressure differences between vegetarians and nonvegetarians.