An observational study appearing in the Journal of the American College of Nutrition (2006; 25(6): 486-92) examined dietary magnesium intake in 1,223 men and 1,485 women without diabetes participating in the Framingham Offspring Study. Dietary intake was assessed using food frequency questionnaires. Subjects in the highest quintile of magnesium intake demonstrated significantly better insulin sensitivity than those in the lowest quintile, suggesting that magnesium intake plays a role in glucose handling even before the development of overt diabetes.
Support for this association comes from a double-blind, placebo-controlled study published in the American Journal of Clinical Nutrition (1992;55:1161-1167), which evaluated the relationship between magnesium status and glucose tolerance. The study involved 25 young healthy men and 12 elderly men who received either the equivalent of 360 mg of magnesium per day or a placebo for four weeks. Subjects receiving magnesium showed increases in red blood cell magnesium levels and improvements in red blood cell membrane microviscosity. Magnesium influences insulin secretion, is required for glucose transport, and plays a critical role in cellular energy production as a cofactor in phosphorylation reactions.
