To prevent colorectal cancer, calcium needs a little help
Old is New Again
What’s old is new again. Depending on who you are, that is.
If you’ve been practicing medicine for years and your methodology begins with nutrition, then you’re HSI Panelist Allan Spreen, M.D., and the “news” about magnesium and calcium is far from new.
But for the conventional doctor who routinely suggests that his patients take calcium supplements to promote healthy bones and prevent colorectal cancer, this news is probably a wake up call: Vitamins, minerals, and other nutrients are usually team players, not loners.
Like a horse and carriage
In previous e-Alerts, HSI Panelist Allan Spreen, M.D., has noted that dietary sources of calcium are typically accompanied by magnesium. So when supplementing with calcium, magnesium supplements should be taken as well. (Foods high in magnesium include leafy green vegetables, whole grains, bananas, apricots, meat, beans, and nuts.)
A new Vanderbilt University study underlines just how important the calcium/magnesium combo is.
The Vanderbilt team reviewed dietary data collected during the Calcium Polyp Prevention Study. I first told you about this research a few years ago. For four years, 930 subjects with colorectal polyps took a 1,000 mg calcium supplement daily or a placebo. Colonoscopy exams showed that subjects in the calcium group generally had fewer polyps compared to the placebo group. Calcium also significantly lowered the risk of advanced polyps.
Scrutinizing the dietary data along with the original results, researchers found that calcium reduced the risk of colorectal polyp recurrence only when the ratio of calcium to magnesium intake was low, before and during treatment.
There will never be another you
Dr. Spreen tells me that he’s always aimed for a calcium-to-magnesium ratio of 2:1, and he still subscribes to that. But he also notes that everyone is unique: “Biochemical individuality means it could vary quite a bit for different people. This one’s not black and white, to me.”
Add to that, most of us would be hard pressed to figure out our exact intake of any individual nutrient on a daily basis. And figuring out actual absorption of nutrients would be even harder. Bottom line: Ensuring an ample intake of dietary and supplemental calcium and magnesium is the key – provided your doctor agrees, of course.
In addition, a good multivitamin appears to help the cause.
A five-year American Cancer Society study of more than 145,000 subjects showed that regular multivitamin use for more than a decade reduced colorectal cancer risk by 30 percent, compared to subjects who didn’t take multis.
And in the e-Alert “Plant Life” (8/21/06), I told you about four flavonoids (plant compounds) that may significantly reduce colorectal cancer risk when intake is high:
1) Flavonols (tea, onions, and broccoli)
2) Anthocyanidins (blueberries and other berries)
3) Isoflavones (beans, lentils, chickpeas, and clove)
4) Flavones (citrus fruit)
Source:
“Abstract A62: Magnesium, Calcium, and Colorectal Adenoma Recurrence: Results from a Randomized Trial” Cancer Prevention Research 1 (7 Supplement), 11/1/08, cancerpreventionresearch.aacrjournals.org
