An inverse association between magnesium and type 2 diabetes has been reported from some studies. For example, researchers1 have used a cohort study of 17,592 Japanese subjects aged 40 to 65 years to investigate the association between magnesium intake and diabetes incidence. Dietary magnesium was estimated from a questionnaire and the incidence of diabetes was recorded from self reported diagnosis by a medical professional. During a 5 year follow-up, 459 cases of diabetes were recorded. The authors reported that dietary magnesium intake was inversely associated with age and incidence of type 2 diabetes (body mass index adjusted) for both men and women. Adjustments for cardiovascular disease during multivariate analysis resulted in a weaker association, but one that was still statistically significant. The odds ratio for diabetes were 0.83, 0.79 and 0.64 for the second, third and highest quartile of magnesium intake, respectively, when compared to the lowest quartile.
The size of this prospective study gives these figures statistical strength and suggests that the inverse association between magnesium intake and type 2 diabetes may be real. However, the possibility for confounding variables cannot be discounted because magnesium intake is associated with fibre intake, a known protective factor against type 2 diabetes. The mechanisms by which dietary magnesium may be protective of type 2 diabetes is thought be predominately through maintenance of correct insulin signalling. Magnesium is required for several enzymes involved in carbohydrate metabolisms and also regulates phosphorylation reactions. Some researchers have theorised that cellular magnesium deficiency may cause insulin disorders due to diminished tyrosine kinase activity on insulin receptors. Some evidence suggests that diabetics may have low magnesium status and supplementation of magnesium have been shown in meta-analysis to decrease fasting glucose levels in type 2 diabetes.
RdB
