DOUBLE-BLIND STUDY OF THREE SODIUM INTAKES AND LONG-TERM EFFECTS OF SODIUM RESTRICTION IN ESSENTIAL HYPERTENSION

doi:10.1016/S0140-6736(89)91852-7

The Lancet

Volume 334, Issue 8674, 25 November 1989, Pages 1244-1247

https://doi.org/10.1016/S0140-6736(89)91852-7 Get rights and content

Abstract

20 patients with mild hypertension (average supine blood pressure without treatment, 164/101 mm Hg) reduced their salt intake to 50 mmol (3 g) per day for a month. They then entered a 3 month double-blind randomised crossover study of three levels of sodium intake: 200, 100, and 50 mmol per day. Blood pressure was significantly reduced on the middle and lowest sodium intakes. The average fall in blood pressure from the highest to the lowest sodium intake was 16/9 mm Hg. Patients continued to restrict their sodium intake for a further year. In 16 of the 20 patients blood pressure remained well controlled with salt restriction alone. Supine blood pressure at 1 year was 142/87 (SE 3/2) mm Hg with a 24 h urinary sodium excretion of 54 (7) mmol. These results show a progressive blood pressure fall as salt intake is reduced and that, in many patients with mild essential hypertension, blood pressure can be controlled without the need for drug therapy.

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We hypothesize that the major environmental determinant of the expression of essential hypertension in America and other Westernized countries is dietary imprudence in respect of the consumption of daily combinations of foods containing suboptimal amounts of potassium and blood pressure-lowering phytochemicals, and supraphysiological amounts of sodium. We offer as premise that Americans on average consume suboptimal amounts of potassium and blood pressure-lowering phytochemicals, and physiologically excessive amounts of sodium, and that such dietary imprudence leads to essential hypertension through oxidative stress-induced vascular endothelial and smooth muscle dysfunction. Such dysfunctions restrict nitric oxide bioavailability, impairing endothelial cell-mediated relaxation of the underlying vascular smooth muscle, initiating and maintaining inappropriately increased peripheral and renal vascular resistance. The biochemical steps from oxidative stress to vascular endothelial dysfunction and its pernicious cardiovascular consequences are well established and generally accepted.
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Citation Excerpt :
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DOUBLE-BLIND STUDY OF THREE SODIUM INTAKES AND LONG-TERM EFFECTS OF SODIUM RESTRICTION IN ESSENTIAL HYPERTENSION

Abstract

Lancet

Clin Chim Acta

Life Sci

Fall in blood pressure with modest reduction in dietary salt intake in mild hypertension

Lancet

Nutritional therapy for high blood pressure: final report of a four-year randomized controlled trial. The hypertension control program

JAMA

Determination of aldosterone in biological fluids

Clinical experience with use of ultrasound sphygmomanometer

Br Heart J