MAGNESIUM SUPPLEMENTATION REDUCES DEVELOPMENT OF DIABETES IN A RAT MODEL OF SPONTANEOUS NIDDM

We examined the effects of a magnesium-supplemented (Mg-S) diet in the male obese Zucker diabetic fatty rat, a model of non-insulin-dependen t diabetes mellitus (NIDDM). Obese rats were maintained on either a co ntrol (0.20% Mg) or magnesium-supplemented (Mg-S; 1% Mg) diet for 6 wk beginning at 6 wk of age. The rats maintained on the Mg-S diet had ma rkedly lower fasting and fed-state blood glucose concentrations and an improved glucose disposal. By 12 wk of age, all of the eight animals on the control diet became diabetic, whereas diabetes developed in onl y one of eight animals on the Mg-S diet. Insulin and C-peptide concent rations, in addition to pancreatic GLUT-2 and insulin mRNA expression, were higher in the male obese Mg-S rats than in their control-fed cou nterparts. A subgroup of rats on the control diet with established dia betes was switched to a Mg-S diet for an additional 4 wk. The Mg-S die t did not reverse diabetes once already established. These data indica te that an increased dietary Mg intake in male obese rats prevents det erioration of glucose tolerance, thus delaying the development of spon taneous NIDDM.