Multivitamins and Mortality-Why Does Only the Bad News
Reach the Media?
Author: Steve Austin, N.D.
Reference: Kwan ML, Greenlee H, Lee VS, et al. Multiple vitamin use and breast cancer outcomes in women with early-stage breast cancer: the Life After Cancer Epidemiology study. Breast Cancer Res Treat 2011;130:195-205.
Design: Observational prospective study
Participants: 2,236 women with previously diagnosed breast cancer (CA) stages I, II, or IIIA
Primary Outcome Measures: Mortality from breast CA, recurrence of breast CA, multi-vitamin use before diagnosis, and multi-vitamin use after diagnosis
Key Findings: 54% of subjects had used a multi before diagnosis, a number that increased to 72% post-diagnosis. 380 recurrence and 212 breast CA deaths occurred during follow-up.
Multi-vitamin use after diagnosis was associated with a statistically nonsignificant 8% reduction in the risks of both recurrence and total mortality. Those who used multi’s both before and after diagnosis had large but statistically nonsignificant reductions in the risk of recurrence (-24%) and total mortality (-21%).
In the subset of women who had had radiation treatment without chemotherapy, the reduction in the risk of recurrence achieved statistical significance (P<0.05). In those who had been treated with both radiation and chemotherapy, the reduction in the risk of a recurrence was highly statistically significant (P=0.015). The authors concluded that “Multivitamin use along with practice of other health-promoting behaviors [exercise and diet high in fruits and vegetables [which were also being tracked] may be beneficial in improving breast cancer outcomes in select groups of women.”
Practice Implications: Recently, the observational Iowa Women’s Health Study reported a positive association between multi-vitamin use and mortality (Arch Intern Med 2011;171:1625-33). The press gave these findings extensive coverage, leaving viewers and readers with the impression that multiple vitamins were killing people. The fact that the report was only observational and not an intervention trial was neither stressed nor explained. The likelihood that some women were taking the vitamins because they were already sick while others may have been taking the vitamins in hopes that it would allow them to get away with a variety of unrelated lifestyle indiscretions (e.g., poor diet, lack of exercise, smoking, and excessive drinking) was also, for the most part, glossed over. The implausibility of the reported findings, in which supplemental intake of vitamin B6, folic acid, magnesium, and zinc were all found to increase mortality to essentially the same extent was never mentioned.
The new report finds links between multi-vitamin use and trends toward reduced mortality and, in some cases, statistically significant reductions in breast CA mortality. These findings tell us very little, given that use of multi’s is likely to be a marker for more healthful lifestyles and there’s a limit to how much of that association can be corrected for through multivariate adjustment.
Thus, the new positive findings have as little meaning as did the seemingly opposite findings of the Iowa Women’s Health Study. But examined from a different perspective, they can also be said to have as much meaning, assuming one attributes any meaning to the findings of the former report. And yet, the media will probably ignore these new findings despite having covered the previous report in detail.
What are the take-home messages? For one, when we rightfully attack those making a mountain out of a molehill in their effort to discredit natural medicine, we must not make the same mistake in favor of natural therapeutics. For another, the media are, for the most part, biased against natural medicine. I believe that the burden of patient education to overcome that bias lies, at least in part, on you-the healthcare professional who employs natural medicine in your practice.