Eat More Magnesium to Avoid Diabetes?

Summarized by Robert W. Griffith, MD
November 10, 2004

Introduction

It's well-known that an appropriate lifestyle (diet, exercise, etc) is likely to lower your risk of developing type 2 diabetes. In particular, eating plenty of whole grains and leafy vegetables has been shown to help. Some researchers have tried to find out whether magnesium, a mineral contained in such healthy foods, could be the (or an) important factor in this protective effect. Their results were published in the Diabetes Care, and we summarize them here.

What was done

The researchers from the Harvard School of Public Health followed 85,000 women and 42,500 men, who were free of diabetes, heart disease, and cancer at baseline, for 18 years (women) or 12 years (men). Information was obtained on weight and height (to give the BMI), physical activity, family history of diabetes, alcohol use, smoking, existence of high blood pressure and high cholesterol levels. Food questionnaires were sent out every 2-4 years, which allowed calculation of the subjects' magnesium intake.

The subjects were divided into five equal groups (called quintiles), depending on their magnesium intake levels. The frequency of occurrence of type 2 diabetes was determined for each group.

What was found

Adjustments were made to exclude any influence on the results of age or the other characteristics listed above. Then the frequency of diabetes in the quintile consuming the highest amount of magnesium was compared with that of the quintile consuming the lowest amount of magnesium. There was a clear-cut difference. The relative risk for diabetes was 0.66 (women) or 0.67 (men) in the high-magnesium group, compared with 1.0 in the low magnesium group. In other words, those consuming the most magnesium were about 2/3 as likely to develop diabetes as those eating little magnesium.

These analyses were repeated after further adjustments for dietary differences such as glycemic load, fat content, fiber content, and processed meats; the findings remained unchanged.

What this means

This study shows that eating foods that contain more magnesium appears to protect someone against developing diabetes, to a certain extent. Another study was reported in the same issue of Diabetes Care, with similar results: in 40,000 subjects from the Women's Health Study, the relative risk of diabetes after 6 years was 0.89 for the highest magnesium-intake quintile.¹ When only women with a BMI of 25 or above were considered, the relative risk sank to 0.78.

With two studies showing the benefits of a high-magnesium diet on the risk of diabetes, it makes sense to look for magnesium-rich foods. These include: whole grains, nuts, and green leafy vegetables. Many people will ask whether they shouldn't be taking magnesium supplements. It's probably better to get your added magnesium by eating a healthy diet containing plenty of magnesium-rich foods. If, however, you want to consider taking magnesium supplements, please look at the first link below.

Source

• Magnesium intake and risk of type 2 diabetes in men and women. R. Lopez-Ridaura, WC. Willet, EB. Rimm,  et al., Diabetes Care, 2004, vol. 27, pp. 134--140

Footnotes
1. Dietary magnesium intake in relation to plasma levels and risk of type 2 diabetes. Y. Song, JE. Manson, JE. Buring, S. Liu, Diabetes Care, 2004, vol. 27, pp. 59--65

Related Links
HealthandAge's Alternative Medicine: Magnesium
Nuts May Help Cut Diabetes Risk
Eat Walnuts for Your Arteries' Sake
Fruits and Vegetables: The Benefits Come From the Sum of Their Parts

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