Hypothesis: low dietary K may lead to renal failure in blacks with hypertension and severe intimal thickening.

Hypertension can precipitate renal failure in blacks. The key hypertensive lesion in the renal vasculature is severe intimal thickening in interlobular arteries without fibrinoid necrosis. Hypertensive endothelial injury is the likely cause of the intimal thickening. High K diets prevent wall thickening of small renal arteries and arterioles in hypertensive Dahl S rats and greatly reduce both medial and intimal thickening of the aorta and mesenteric and carotid arteries in hypertensive stroke-prone SHRsp rats. In view of this, it is likely that the low K diet characteristically consumed by blacks exaggerates their hypertensive intimal thickening. A high K diet could possibly preserve these arteries and avert much renal failure.