High sodium chloride diets injure arteries and raise mortality without changing blood pressure

Abstract

High NaCl diets often increase blood pressure and thereby accelerate lesions in arterial walls. Could high NaCl diets increase arterial lesions without raising blood pressure? To test this, 100 uninephrectomized Dahl salt-resistant (DR) rats (highly resistant to NaCl hypertension) were administered deoxycorticosterone acetate (DOCA) (250 mg/kg) in silicone implants and drinking water containing 1% NaCl for 6 weeks. Then the DOCA and saline were removed, and the rats were allowed to recover for 4 weeks. Intra-arterial mean blood pressures on all rats allowed division of the rats into two matched groups, each group with an average blood pressure of 160 mm Hg. One group continued on a 0.3% NaCl diet, whereas the other group began an 8% NaCl diet for 8 weeks. After 5 weeks on these two diets, the intra-arterial blood pressure averaged 158 mm Hg in both groups. Thus, the 8% NaCl diet produced no further increase in blood pressure in the DR rats. Nevertheless, alter 8 weeks on the 8% NaCl diet, 53% of the rats (26 of 49) had died; whereas in the group on the 0.3% NaCl diet, not one rat (0 of 51) had died (p<0.000001). After 7 more weeks on the 8% NaCl diet, all the rats in this group had died. The chief cause of death in the group of rats on the 8% NaCl diet was likely cerebral infarction because small cerebral infarcts were observed in rats that died on this diet. Uremia, congestive failure, cerebral hemorrhage, and arrhythmia were not likely causes of death. Thus, it appears that a high NaCl diet in mildly hypertensive DR rats can greatly accelerate cerebral arterial disease with brain infarction and very high mortality, even when the high NaCl diet causes no increase in blood pressure whatsoever. Seemingly, salt's infamy goes beyond blood pressure. It is even possible that “salt-resistant” hypertensive humans could reduce vascular complications by adhering to a low NaCl diet. © 1990 American Heart Association, Inc.