Last October I wrote a post cautioning readers about the risks of vitamin supplementation. Mega-dosing vitamins pose health problems such as a higher risk of cancer. Based on oncologist Dr. Larry Norton’s advice I argued that daily multivitamins pose similar risks.
Looks like I need to take that last part back. A large well-done study has recently come out that found a statistically significant reduction in the number of participants developing cancer if they took a daily multivitamin.
Conclusion In this large prevention trial of male physicians, daily multivitamin supplementation modestly but significantly reduced the risk of total cancer.
That was also a cohort study. All kinds of biases, and there’s no way that it can test for causation.
Now I’m not dismissing cohort studies out of hand. But the results of the study you link to should make one pause and say, “There appears to be an association between MVI use and mortality. Maybe we should test that with an RCT.”
They did one. It’s the study I talked about. It showed that MVIs reduce mortality. This was huge RCT with years-long follow-up.
Just so everyone knows, an “RCT” is a “randomized controlled trial,” and, as Wikipedia notes, have “a superior methodology in the hierarchy of evidence in therapy.”
What publication are you writing for and what is your deadline?
I told her and she wrote back:
I’m sorry but Dr. Norton is unavailable to weigh in.
I wrote back asking if anyone at the MSKCC “has a position generally on whether it is a good idea to take a multivitamin daily?” I haven’t received a response.
Well, until we learn anything new it looks like taking a daily multivitamin is a good idea, but mega-dosing specific vitamins or supplements is still inadvisable.