Magnesium Lowers Colon Cancer Risk

Researchers from the Vanderbilt Epidemiology Center, Vanderbilt University School of Medicine investigated the importance of serum magnesium and calcium levels on colon cancer risk. They found that serum magnesium levels were significantly lower – and that the ratio of calcium to magnesium was significantly higher – among men with high-grade or more aggressive colon cancer compared to men without colon cancer.

Serum calcium levels alone were not significantly associated with high or low-grade colon cancer.

The findings reported that magnesium affects colon cancer risk, perhaps through its interactions with calcium, and may provide an important path to the prevention of colon cancer.


According to Qu Dai, MD, PhD, Americans have a high calcium intake, but also a high incidence of colorectal cancer. “If calcium levels were involved alone, you’d expect the opposite direction. There may be something about these two factors combined – the ratio of one to the other – that might be at play,” said Dai.

“The risk of colorectal cancer adenoma recurrence was reduced by 32 percent among those with baseline calcium to magnesium ratio below the median in comparison to no reduction for those above the median,” said Dai.

Research Study

Am J Clin Nutr. 2007 Sep;86(3):743-51.

The relation of magnesium and calcium intakes and a genetic polymorphism in the magnesium transporter to colorectal neoplasia risk.
Dai Q, Shrubsole MJ, Ness RM, Schlundt D, Cai Q, Smalley WE, Li M, Shyr Y, Zheng W.
Vanderbilt Epidemiology Center, Vanderbilt University School of Medicine, Nashville, TN 37203-1738, USA.



Mean magnesium intake in the US population does not differ from that in East Asian populations with traditionally low risks of colorectal cancer and other chronic diseases, but the ratio of calcium to magnesium (Ca:Mg) intake is much higher in the US population. Transient receptor potential melastatin 7 (TRPM7) is a newly found gene essential to magnesium absorption and homeostasis.


We aimed to test whether the association of colorectal polyps with intake of calcium, magnesium, or both and Thr1482Ile polymorphism in the TRPM7 gene is modified by the Ca:Mg intake.


Included in the study were a total of 688 adenoma cases, 210 hyperplastic polyp cases, and 1306 polyp-free controls from the Tennessee Colorectal Polyp Study.

We found that total magnesium consumption was linked to a significantly lower risk of colorectal adenoma, particularly in those subjects with a low Ca:Mg intake. An inverse association trend was found for hyperplastic polyps. We also found that the common Thr1482Ile polymorphism was associated with an elevated risk of both adenomatous and hyperplastic polyps. Moreover, this polymorphism significantly interacted with the Ca:Mg intake in relation to both adenomatous and hyperplastic polyps. The subjects who carried >or=1 1482Ile allele and who consumed diets with a high Ca:Mg intake were at a higher risk of adenoma (odds ratio: 1.60; 95% CI: 1.12, 2.29) and hyperplastic polyps (odds ratio: 1.85; 95% CI: 1.09, 3.14) than were the subjects who did not carry the polymorphism.


These findings, if confirmed, may provide a new avenue for the personalized prevention of magnesium deficiency and, thus, colorectal cancer.

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