Adverse effects of short-term, very-low-salt diets in subjects with risk-factor clustering.

Obesity is associated with risk-factor clustering, including risk factors for hypertension, hyperinsulinemia, resistance to insulin's lowering of glucose and fatty acid concentrations, and a complex dyslipidemia. Obese hypertensive subjects are presumed to be salt sensitive because of the antinatriuretic actions of insulin. However, in our studies obese hypertensive subjects aged < 45 y were not more salt sensitive than were lean individuals. Subjects with the greatest evidence for risk-factor clustering had higher renin and aldosterone concentrations, which increased with salt restriction. The greater rise of fatty acids and activation of the renin-angiotensin system may explain the larger elevations of blood pressure, insulin, and triacylglycerol with salt restriction in high-risk subjects than in low-risk subjects. Regardless of mechanism, the adverse effects of short-term, very-low-salt diets in high-risk subjects suggest that continued moderation in advice for universal salt restriction is appropriate.