Dietary Magnesium Linked to Lower Colon Cancer Rates


A new study again casts the spotlight on magnesium, an often-overlooked mineral thats now getting noticed for health benefits ranging from diabetes to stroke prevention. (See our Special Report on magnesium in the September newsletter.) In the latest research, British and Dutch scientists report a possible link between greater magnesium from the diet and lower risk of colorectal cancer.

Petra A. Wark, MSc, PhD, of Imperial College London and colleagues compared dietary magnesium intake among 768 patients with colorectal adenomas (polyps) and 709 healthy control subjects. For every 100-milligram increase in magnesium from foods-about the amount in a cup of beans or two potatoes-the risk of adenomas dropped 19%. That association was limited, however, to people with a BMI of 25 or over or those who were at least 55 years old, or to advanced adenomas.

The scientists also analyzed data from nine previous studies. In that review, every additional 100 milligrams of magnesium from the diet per day was linked to a 12% lower risk of colorectal cancer and a 13% decrease in the risk of adenomas.

But Wark cautions, The association observed in the case-control study was not statistically significant, and we cannot therefore be confident that theres an association in this study (it may well have been due to chance). In the meta-analysis, the associations were statistically significant-but as there were only nine studies, we also require further studies to learn more. The consumption of magnesium-rich foods may be a new avenue to explore further in the search for cancer-prevention strategies.

Foods high in magnesium include:

Wheat bran




White potatoes

Pinto beans

Brown rice


Bananas This information is very interesting and very provocative and therefore deserves a lot more attention on the part of future investigators, comments Joel B. Mason, MD, director of Tufts HNRCA Vitamins and Carcinogenesis Laboratory, but I believe it would be premature to use this to make dietary recommendations. All the data, including the new case-control study as well as the studies integrated into the meta-analysis, are epidemiological studies and therefore can not prove causality.

TO LEARN MORE: American Journal of Clinical Nutrition, September 2012; abstract at


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