BACKGROUND. An effect of diet in determining blood pressure is suggested by epidemiological studies, but the role of specific nutrients is still unsettled.

METHODS AND RESULTS. The relation of various nutritional factors with hypertension was examined prospectively among 30,681 predominantly white US male health professionals, 40-75 years old, without diagnosed hypertension. During 4 years of follow-up, 1,248 men reported a diagnosis of hypertension. Age, relative weight, and alcohol consumption were the strongest predictors for the development of hypertension. Dietary fiber, potassium, and magnesium were each significantly associated with lower risk of hypertension when considered individually and after adjustment for age, relative weight, alcohol consumption, and energy intake. When these nutrients were considered simultaneously, only dietary fiber had an independent inverse association with hypertension.

For men with a fiber intake of < 12 g/day, the relative risk of hypertension was 1.57 (95% confidence interval, 1.20-2.05) compared with an intake of > 24 g/day. Calcium was significantly associated with lower risk of hypertension only in lean men. Dietary fiber, potassium, and magnesium were also inversely related to baseline systolic and diastolic blood pressure and to change in blood pressure during the follow-up among men who did not develop hypertension. Calcium was inversely associated with baseline blood pressure but not with change in blood pressure.

No significant associations with hypertension were observed for sodium, total fat, or saturated, transunsaturated, and polyunsaturated fatty acids. Fruit fiber but not vegetable or cereal fiber was inversely associated with incidence of hypertension.

CONCLUSIONS. These results support hypotheses that an increased intake of fiber and magnesium may contribute to the prevention of hypertension.