In a double-blind, placebo controlled study, researchers divided 69 type-2 diabetics into four groups. The research was published in Diabetes Care (2005; 28(10):2458-64). One group received 200 milligrams of magnesium and 30 milligrams of zinc each day for three months. Another group received 200 milligrams of vitamin C per day and 100 IU of vitamin E for the three months. Another group received both the minerals and the vitamins for the three months, and a fourth group received a placebo. Two tests of kidney function, urinary albumin excretion and N-acetyl-beta-d-glucosaminidase activity (NAG) in urine were determined at the beginning and at the end of the trial.
After three months of supplementation, the albumin excretion decreased in both the group receiving vitamins C and E and in the group receiving the combination of vitamins and minerals. The NAG did not change in any of the groups. The authors concluded that taking vitamins C and E and taking the combination of magnesium, zinc, and vitamins C and E improved glomerular but not tubular renal function in type 2 diabetic patients. The group taking both the vitamins and minerals enjoyed the benefits of higher HDL (good cholesterol) and lower fasting blood sugar.