There are four simple steps you can take to reduce your risk of colorectal cancer, according to studies I've discussed in other alerts:
1) Take a daily multivitamin
2) Get plenty of vitamin D (preferably from short periods of daily sun exposure)
3) Eat ample amounts of fresh fruits and vegetables
4) Get a colonoscopy
Okay, I admit, that last one isn't so simple, but it's extremely effective because colonoscopy not only looks for cancer polyps, it also removes them, sharply reducing cancer risk. With today's alert we'll add one more item to that list. And the good news: Like the first three items, it's simple and easy - and non-invasive. In previous alerts we've looked at the many benefits of adequate magnesium intake. Studies have shown that magnesium may promote bone flexibility while helping to prevent heart disease and type 2 diabetes. As if that scorecard wasn't impressive enough, animal studies indicate that dietary magnesium may also provide protection against colorectal cancer. With research in this area relatively unexplored with humans so far, scientists at the Karolinska Institute in Stockholm, Sweden, prepared a population-based study using information from the Swedish Mammography Cohort. The Karolinska team gathered dietary and medical records on more than 61,000 women, aged 40 to 75 years, who were cancer-free at the outset of the study. Over a follow up period of nearly 15 years, about 800 cases of colorectal cancer were diagnosed. Analysis of the data showed that women with the highest dietary intake of magnesium reduced their risk of colorectal cancer by 40 percent, compared to women who had the lowest magnesium intake. This association held true when data was broken down to reflect cases of colon cancer or rectal cancer. Dietary magnesium is easy to come by. The mineral is naturally present in green leafy vegetables, avocados, nuts and seeds, and whole grains, but usually in small amounts, so you need to eat a wide variety of these foods regularly to get all the magnesium you need. In a previous alert I told you about research indicating that as many as half of the adults in North America may not be getting enough magnesium in their diets. This is largely due to the stresses on the body that deplete stores of magnesium. Starch, for instance, depletes magnesium, as does stress. You may also be at increased risk for magnesium deficiency if you regularly consume alcohol or diuretics because both can increase urinary excretion of the mineral. Prescription medications, like the antibiotics Gentamicin, Amphotericin, and Cyclosporin, can increase magnesium excretion as well. When I asked panelist Allan Spreen, M.D., to give us his thoughts on magnesium supplementation, he shared some information from the National Institutes of Health, which recommends 420 mg daily for men over the age of 31, and 320 mg daily for women of the same age group. But it's not quite that cut-and-dried, because, as Dr. Spreen points out, there are other questions to be considered: "I've always recommended 500 milligrams/day, since absorption of most forms isn't that great anyway, and I like to let people get the cheapest and easiest sources they can. "My limit for oral magnesium is that which causes any loosening of the stools (and there's always a distinct dose that will do it...in fact, it works like a charm for constipated people by taking a known dose at bedtime, plus it helps them sleep!). I'm careful to warn people not to go over that limit for the simple reason that food is moved through the GI tract too quickly with too much magnesium, and that cuts down on absorption of nutrients (both from foods and supplements). However, that amount is usually between 400 and 1500 milligrams/day. "The new RDI (as of 2002, anyway) in the US is 400 mg/day. Now, bear in mind that that's ELEMENTAL magnesium. In a supplement, such as magnesium oxide (a poor form, but wouldn't you know that's what a drug company uses for low magnesium levels in the official Physician's Desk Reference), the tablet that is sold as a 400 milligram tablet only has 241.3 milligrams of elemental magnesium. So, when you take a '400 milligram' tablet, you aren't getting 400 milligrams of magnesium anyway. Plus, even the label says you can take 2/day, or 800 milligrams." If you're concerned that you might have a magnesium deficiency, ask your doctor to test your blood for magnesium levels. A normal range is anywhere between .66 and 1.23 mmol/L (millimoles per liter). Then you can be reassured that your magnesium intake is getting absorbed to deliver all the benefits from this essential nutrient.