MODERATE DIETARY SALT RESTRICTION DOES NOT ALTER INSULIN-RESISTANCE OR SERUM-LIPIDS IN NORMAL MEN

Dietary salt restriction lowers blood pressure and has been advocated as a population-based strategy to reduce the cardiovascular morbidity associated with hypertension. However, the effect of lowering salt int ake on metabolic vascular risk factors such as insulin resistance and levels of atherogenic lipids and fasting insulin is uncertain. We have studied the short-term effect of moderate dietary salt restriction on insulin resistance and serum lipids in 34 nonobese (body mass index [ mean +/- SD] 23.4 +/- 1.8 kg/m(2)), normotensive young white men. Subj ects were maintained on a low salt diet (<80 mmol/day) for the 2-week study period. In a randomized, cross-over, double-blind fashion, each subject also received 120 mmol of sodium chloride per day during one o f the study weeks, and a matching placebo during the other. Insulin re sistance, serum insulin, lipids, and blood pressure were measured in t he fasting state at the end of each study week. Urinary sodium excreti on (185 +/- 46 v 52 +/- 25 mmol/day, P < .001), serum sodium (141.2 +/ - 1.2 v 140.1 +/- 1.3 mmol/L, P < .001) and body weight (75.4 +/- 9.1 v 75.0 +/- 9.3 kg, P < .05) were higher during the high salt than the low salt period. Serum creatinine was higher during the low salt perio d (100 +/- 8 v 90 +/- 9 mu mol/L P < .01). There was no difference in blood pressure, insulin resistance, serum insulin, C-peptide, total ch olesterol, low density lipoprotein cholesterol, high density lipoprote in cholesterol or its subfractions, triglycerides, apolipoprotein A1, or apolipoprotein B between the high salt and low salt periods. We con clude that short-term, moderate dietary salt restriction does not adve rsely affect insulin sensitivity or levels of atherogenic lipids in no rmotensive nonobese men.