Cancer
Low magnesium, high calcium boosts colorectal cancer risk
By Sarah Han
Nov 29, 2008 - 9:08:02 PM

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Saturday Nov 29, 2008 (foodconsumer.org) -- Some researchers believe that drinking milk or eating dairy products is a risk factor for colorectal cancer.   A new study has found additional evidence to support the notion.

The study showed that people whose diet had a higher ratio of calcium to magnesium were more likely to have colorectal cancer. The ratio of calcium to magnesium in milk is high.

Early studies showed that Asian people have low incidence of colorectal cancer than American people even though they have similar intake of magnesium.    And Asians who immigrated to the U.S. became more susceptible to the disease years later.

Both observations together prompted researchers to speculate that there might have something to do with intake of calcium because milk with high calcium is far much more commonly used in the U.S. than Asian countries.

Dai Q and colleagues of Vanderbilt University School of Medicine wanted to examine if there is an association of colorectal polyps with intake of calcium, magnesium, or both and a gene mutation called The1482Ile in the gene TRPM7 is modified by the minerals.

The study involved 688 adenoma cases, 210 hyperplastic polyp cases, and 1306 polyp-free controls from the Tennessee Colorectal Polyp Study.

The researchers found total intake of magnesium was correlated to a significantly reduced risk of colorectal adenoma, particularly in those who used a diet with low calcium and high magnesium.   There was an inverse association between the ratio of calcium to magnesium for hyperplastic polyps.

They also found that of participants who had a high ratio of calcium to magnesium in their diet, those who carried the gene variant were 60 percent more likely to have adenoma and 85 percent more likely to have hyperplastic polyps.

In a word, a high calcium and low magnesium diet may increase risk of colorectal cancer.   The most abundant sources of calcium are milk and dairy products although beans and green vegetables are also calcium-rich.   Magnesium is found abundantly in 100% bran cereal, oat bran, shredded wheat, brown rice, almonds, hazelnuts, peanuts, lima beans, frozen chopped spinach, and Swiss chard.