Colon Cancer Incidence Reduced by Magnesium Rich Foods?

Medical study finds an inverse link between magnesium intake and colon cancerYet more studies have provided evidence that magnesium rich foods may reduce the risks of colon cancer. No surprises here, though more work needs to be done in this area.

The Journal of Nutrition published a study by doctors at the National Cancer Center in Tokyo, Japan involving 40,000 men and 46,000 women, an reassuringly large sample for testing.
The 40,830 men and 46,287 women were followed up for 8 years. This study did not include an analysis of supplement use among participants. It focused strictly on magnesium intake from foods and dietary sources.

The study showed that higher intake of dietary magnesium was strongly associated with a decreased risk of colorectal cancer (colon cancer) in men. The study, however, showed no such correlation among the women. Investigators speculate that this discrepancy between the genders may be partly due to differences in alcohol consumption. Japanese men consume nearly four times as much alcohol as women, and that magnesium may counteract the oxidate stress of alcohol.

The investigators acknowledge that beneficial associations between magnesium intake and CRC risk may include the influence of other nutrients from foods, as participants with higher intakes of magnesium also tended to consume higher intakes of foods rich in calcium, zinc, fiber, folate, B-6 and vitamin D. Researchers conclude by stating “Increased intake of magnesium-rich foods is recommended if other studies, including randomized control trials, confirm our findings.”

The findings show a strong 52% reduction in colon cancer among men whose daily intake of magnesium was 327mg or greater, as opposed to the group whose intake was 238mg or less.

This was the latest of several studies suggesting a link between insufficient magnesium intake and colon cancer, including a Swedish study that showed magnesium reducing the chances of colon cancer in women. This study included supplements, and readers should note that Swedish women and Japanese women have very different genetic predispositions and diets.

Two things that are worth repeating here…

One is that increased consumption of magnesiumĀ  rich foods almost guarantees that you will be getting more of all kinds of good nutrition. Again, foods that are high in magnesium tend to be very healthy and nutritious foods to begin with. So, by targeting more magnesium in your diet, you are in fact improving your diet in countless ways that you do not even know of.

The second point is the relation between alcohol and magnesium. While not mentioned by the doctors in the study above, alcohol consumption is know to decrease the magnesium levels in your cells. Obviously, eating A Japanese man who drank too much, a common sight at train stations in the eveninga magnesium rich diet would help to counteract this. This may have also played a role in the Japanese study, as Japanese men do tend to drink much more than Japanese women (though many Japanese women are surprisingly strong drinkers as well).

Keep this in mind if you drink more than you should, and at least try to balance it out with a healthy diet of foods high in magnesium.

Magnesium Absorption and Effects of Other Supplements

Magnesium and fat from pork - what's the deal?The good news is, the fat you eat may be giving you more magnesium – even though it may not be a magnesium rich food itself.

At least sometimes.

This shouldn’t be a surprise, despite the demonization of fat, it has been a staple part of the human diet dating back to dawn of hunting and fire. Indeed, insufficient fat was a much bigger concern throughout most of history. As always, abundance turns the world upside down, and fat got on the wrong side of many dieticians, not to mention dieters.

Well, here’s a reason to make sure you have at least some fat in your diet. But, before you get too exited, evidence has shown that excess fat can actually block the absorption of magnesium.

So here goes – things that help you absorb more magnesium:


A study by the American Journal of Clinical Nutrition (Vol. 80, No. 2, 396-403, August 2004) looked at a small group of people to compare their absorption of carotenoids when eating salads with fat-free dressing as opposed to regular salad dressing with oil. Lo and behold, those who went fat-free absorbed almost no carotenoids, suggesting that the fat was needed for the body to access the nutrients.

I am very much opposed to “fat-free” concoctions for a number of reasons, not least being the manufactured crap they use to trick your body into tasting fat. Here’s another. If you’re worried about too much fat, do the old fashioned thing and reduce your portions. Your portions may be small, but at least they’ll be real, delicious and healthy.


Often cited as assisting magnesium absorption, there is very little evidence either way. But, since vitamin C is generally good for you, I’d rather err on the side of taking my supplements.


A 1972 study in the International Urology and Nephrology Journal in the Netherlands suggested that vitamin D could be helpful in assisting patients who needed greater absorption of magnesium through the intestine. This has been backed up by other studies, including “The Journal of Nutrition” study published in 1991.

However, and this is a big “however,” the 1991 study showed that vitamin D greatly increased the excretion of magnesium through the urine!

Easy come, easy go.

The jury is out on Vitamin D, but at the very least vitamin D supplements would seem to be unnecessary for magnesium absorption.


This is a biggy. Many websites will tell you that calium is a magnesium antagonist, inhibiting its entry into cells. Other sites will tell you that they need each other. Magnesium helps calcium to work, and vice versa. They are in fact friends.

Not to confuse you, but all of the above appears to be true. Maybe it’s best to think of calcium of magnesium as a turbulent married couple (or even Tweedledee and Tweedledum)- not always helpful to each other, yet they both needCalcium and Magnesium are Tweedledum and Tweedledee the other. There’s a fine balance between the blow out fights, the affairs, and the love and support.

In the case of magnesium and calcium, many people have decided that the ration of 2 parts calcium to one part magnesium is this perfect ration.

This 2 to 1 ratio appears to be plucked out of thin air.

In fact, in Japan, which has a very low rate of heart disease, the ration is closer to 1/1.

The only thing I can say here is to take it easy on the calcium supplements.


Long term, and massive doses, of oral vitamin B6 appear to boost magnesium levels. Since massive doses of anything should only be administered by a competent physician, just put this in the back of your mind. B6 shots will temporarily boost magnesium levels, and at the same time crash your calcium levels. So while B6 does encourage magnesium retention, it’s not something you’d want to try lightly.


If you’re getting your magnesium from mineral water, a 2002 study published in the American Journal of Clinical Nutrition showed that, while 50% of the water’s magnesium was absorbed when drunk without food, that amount greatly increased when the water was taken with a meal. To which we say “bon apetit!”

Going back to the fat, since most magnesium rich nuts, such as almonds and cashews, contain oil, you’re probably better off munching on them. So far as other supplements to boost your magnesium absorption, just forget it. Keep your consumption of alcohol, caffeine and carbonated drinks to a minimum, eat fresh foods, and especially green leafy things. Don’t go into mad scientist mode trying to make the perfect supplement concoction. Eat foods high in magnesium and enjoy life!