Abstract P329: Moderate Dietary Sodium Restriction Does Not Alter Insulin Sensitivity Or Secretion In Metabolic Syndrome

Abstract

We previously demonstrated that maximal dietary sodium restriction (10mmol/d) decreases insulin secretion and impairs insulin secretion. It is unclear if dietary changes other than NaCL account for this and if more moderate sodium restriction reflecting clinically achievable ranges would alter glucose metabolism. We therefore hypothesized that moderate diet-induced stimulation of the renin-angiotensin-aldosterone system would impair insulin secretion in participants with the metabolic syndrome. We conducted a randomized, double-blind cross-over study in 29 volunteers in which we provided a standardized 50mmol Na/day diet for 7 days. Participants were provided encapsulated NaCl 150 mEq/d (High Sodium, HS) or matching placebo capsule (Low Sodium, LS) for 7 days. Insulin sensitivity was assessed with hyperinsulinemic clamp and insulin secretion was assessed with hyperglycemic clamp at 5 and 7 days of diet, respectively. LS diet increased plasma aldosterone compared to HS diet (15.2±6.2 vs 10.8±3.2; P <0.001) but did alter blood pressure (126.5±13.6 vs 128.7±13.9 mmHg; P =0.49). Fasting glucose and insulin were similar during LS diet. As assessed by hyperinsulinemic clamps, insulin sensitivity was similar (0.2756 ± 0.0771 vs 0.2917 ± 0.0722 mg/kg/min per uU/mL Insulin; P =0.49). Insulin clearance tended to decrease during the LS period (980 ± 410 vs 1127 ± 366; P=0.10). There was no difference in glucose-stimulated insulin secretion assessed by hyperglycemic clamp (55.3 ± 47.7 vs 50.0 ± 36.7 uU/ml; P=0.7). Dietary sodium restriction achievable dose not alter glucose and insulin metabolism in the short term.