High potassium diets markedly protect against stroke deaths and kidney disease in hypertensive rats, a possible legacy from prehistoric times

Abstract

Male spontaneously hypertensive stroke-prone (SHRsp) rats were fed 4% NaCl diets containing either 0.75% (normal) K or2.11% (high) K, starting at 6 weeks of age. After 8 months on these diets, 40 out of 58 SHRsp rats on the 0.75% K diet had died(69% mortality) versus 2 dead out of 95 on the 2.11% K diet (2% mortality), a 97% reduction in mortality, p < 0.00001. After 20weeks on the diets, the daytime and night time blood pressures of each rat were measured intraarterially under light ether anesthesia. Using these accurate blood pressures, we selected two groups precisely matched for blood pressure. One matched SHRsp group (BP 182) ate the 0.75% K diet and 30 out of 47 rats died (64% mortality). The other matched SHRsp group (BP 182) ate the 2.11% K diet and 2 out of 35 died (6% mortality), a 91% reduction of mortality, p < 0.0001. Seemingly, this striking reduction in mortality rate with the 2.11% high K diet does not depend on a lowering of blood pressure. High K diets do not change body Na or K. Dry weight of mesenteric arterioles was reduced 29% on the 2.11% K diet versus the 0.75% K diet (5.43 vs. 7.66 mg) (p < 0.0001), indicating a greatly reduced hypertensive hypertrophy. In nine surviving SHRsp rats on the 0.75% K diet, 13 of 36 brain hemisphere slides (4 slides per rat) showed infarcts (36%). In 11 surviving SHRsp rats on the 2.11% K diet, 1 of 44 brain slides showed infarcts (2%), a 94.5% reduction, p < 0.0001. High K diets allow cerebral arteries to carry very high blood pressures without sustaining damage to the artery wall, thereby drastically reducing brain infarcts and lowering the death rate.