Magnesiumsupplementation may reduce the risk of diabetes

Compared with a placebo, daily supplementation with magnesium for six months was shown to improve two of the three measures of insulin sensitivity, and to reduce fasting blood sugar by almost 7%.
In a study conducted by German researchers, 52 volunteers were given 365mg of magnesium a day, or a placebo, for a period of 6 months. The subjects had normal magnesium levels, were insulin-resistant and overweight but not diabetic.
The results echo those of a meta-analysis of observational studies published in 2007: researchers at the Karolinska Institute in Sweden, reported that for each increase of 100 mg magnesium, the risk of developing type II diabetes diminished by 15%.
It underlines the importance of optimising magnesium intake at an early stage to prevent insulin resistance and type II diabetes.

(Diabetes, Obesity and Metabolism, “accepted article” published online ahead of print, doi : 10.111/j.1463-1326.2010.01332.x)