Wednesday 13 June 2012

Should you take extra vitamin D and calcium?


Here’s the problem if, as most people do, when you run across a medical news story that might affect you, you read only headlines or at most a paragraph or three: you often get a totally wrong impression of what that study or report was really about.

That’s certainly what’s going to happen to a lot of people who only cursorily read a recent report about vitamin D and calcium supplements, a report that affects millions and millions of people.

This report was a draft recommendation from the U.S. Preventive Services Task Force, a government body with a mandate to review current preventive strategies and recommendations, and the experts on this body often swim against the popular tide, as they did in coming out recently with a recommendation against routine screening for prostate cancer.

So in their most recent recommendation, the USPSTF has really roiled some experts because it has come out strongly opposed to low-dose supplementation with vitamin D and calcium for the prevention of fractures in post-menopausal women.

Please note: that’s low-dose supplementation, which the PSTF defined as 400 IU of vitamin D and 1,000 mg of calcium.

When it comes to higher doses, such as the one so many experts think may be appropriate for such women, namely 800 IU of vitamin D, the PSTF says there is not enough evidence either for or against this dose; in other words, it might work, it might not.

Yet nearly every news story about this recommendation came out with a headline like this one: USPSTF Says No to Vitamin D, Calcium for Older Women.

Well, no, it didn’t.

It said no to a low dose, maybe to a higher one, so women taking a higher dose may be doing the right thing although we need way more data about that choice.

Equally interesting, the PSTF came out very strongly opposed to recommending the use of vitamin D for cancer prevention, which flies in the face of recommendations from many authoritative groups like the Canadian Cancer Society for example, who do recommend taking vitamin D for cancer prevention.

But as I have been saying for years and the PSTF agrees with me, it’s still very unclear that extra vitamin D will in fact reduce the risk of cancer.

Even if it is an anti-cancer agent, we still don’t know what form of vitamin D to recommend for that purpose (vitamin D is sold mostly as vitamin D 2, although lots of experts believe that vitamin D3 is far more effective at doing what vitamin D is supposed to do.

And we clearly also don’t have a clue about the dose that’s needed. Or whether some people are genetically more susceptible to(or protected against) a low vitamin D blood level.

Andon and on.

Whether or not to take vitamin D supplements (and/or calcium supplements, which have been linked several times to a higher risk of heart attacks) remains an individualized decision based on many variables: inform yourself thoroughly about the pros and cons and then decide for yourself what to do.