Salt intake and insulin sensitivity in healthy human volunteers

Clin Sci (Lond). 2007 Aug;113(3):141-8. doi: 10.1042/CS20060361.


The literature on salt intake and insulin sensitivity presents a mixed picture, as some studies have shown an increase, whereas others have shown a decrease, in insulin action as sodium intake is enhanced. In some cases, this may relate to the study of salt intake in patients with co-morbidities such as hypertension or diabetes. In the present study, we selected healthy normotensive lean volunteers who underwent a euglycaemic clamp following 6 days of a low-salt diet (20 mmol sodium daily) and, subsequently, 6 days of a high-salt diet (200 mmol sodium daily). Our results show an increase in insulin-mediated glucose disposal during euglycaemic clamp conditions that was significantly higher following the high-salt diet compared with the low-salt diet (7.41+/-0.41 compared with 6.11+/-0.40 mg x kg(-1) of body weight x min(-1) respectively; P=0.03). We measured calf blood flow before and during insulin infusion (no significant change after the two dietary salt interventions was detected) and plasma non-esterified fatty acids (also no significant differences were detected). We observed the expected increases in renin concentration and aldosterone activity in subjects on the low-salt diet, and also observed a significantly less increase in plasma noradrenaline concentration during euglycaemic insulin infusion following the high-salt compared with the low-salt diet. We propose that the 4-5-fold increase in serum aldosterone and the greater increase in plasma noradrenaline concentration following the low-salt intervention compared with the high-salt period may have contributed to the differences in insulin sensitivity following the adjustment in dietary sodium intake.

Publication types

  • Randomized Controlled Trial
  • Research Support, N.I.H., Extramural

MeSH terms

  • Adult
  • Aldosterone / blood
  • Blood Glucose / metabolism
  • Blood Pressure / drug effects
  • Body Weight / drug effects
  • Calorimetry / methods
  • Diet, Sodium-Restricted
  • Fatty Acids, Nonesterified / blood
  • Female
  • Glucose Clamp Technique
  • Heart Rate / drug effects
  • Humans
  • Insulin Resistance / physiology*
  • Leg / blood supply
  • Male
  • Norepinephrine / blood
  • Regional Blood Flow / drug effects
  • Sodium Chloride, Dietary / administration & dosage*
  • Sodium Chloride, Dietary / pharmacology


  • Blood Glucose
  • Fatty Acids, Nonesterified
  • Sodium Chloride, Dietary
  • Aldosterone
  • Norepinephrine