EFFECTS OF DIETARY-SODIUM SUBSTITUTION WITH POTASSIUM AND MAGNESIUM IN HYPERTENSIVE TYPE-II DIABETICS - A RANDOMIZED BLIND CONTROLLED PARALLEL STUDY

We have previously demonstrated that modest sodium restriction has a h ypotensive effect in hypertensive diabetic subjects, A randomised blin d controlled study has therefore been performed to study the effect of replacement of added salt intake using a salt substitute (50% NaCl, 4 0% KCL, 10% Mg2+, supplied by Cederroth, Sweden), compared to added wh ole salt intake over a 9 month period of 40 hypertensive Type II diabe tic subjects (mean age 62.5+/-7.8 years; 24 males and 16 females). Aft er 3 months, there was a significant reduction in systolic blood press ure (SEP) in the salt substitution group (163.2+/-24.2 to 153.6+/-20.8 mm Hg; P < 0.03) which was maintained at 9 months, when compared to t he whole salt group (151.5+/-20.6 vs 173+/-18.9 mm Hg; P < 0.05), No s ignificant changes were observed in mean weight, fasting lipid or insu lin levels or diabetic control (measured by glycosylated haemoglobin). A greater number of patients were withdrawn during the study period o wing to consistent BP > 160/95 in the whole salt group (n=10) compared to salt substitute (n=4), No significant changes were observed in dia stolic pressure, 24-h urine sodium or magnesium excretion, but urine p otassium was significantly increased in the salt substitute group (58. 8 to 77.3: P < 0.05). The results of this study suggest that substitut ion of sodium, by potassium and magnesium, produces a clinically signi ficant reduction in SEP in hypertensive Type II diabetic patients, and should be a useful antihypertensive therapy in this patient group.