Vitamyths

By Jim McVeagh 29/12/2011


Vi♦ta♦myth [vahy-tuh-mith; Brit. also vit-uh-mith]

A factoid about vitamins that is wildly inaccurate or untrue

Vitamyths come from both ends of the vitamin spectrum. Those who promote the consumption of vast amounts of vitamins are usually happy to make outlandish claims about their efficacy. This is, in some ways, quite understandable, as it is in the nature of merchandising to exaggerate. Less understandable is the tendency of clinically orientated professionals to magnify the significance of every negative result while completely ignoring any positive findings. An excellent example of this can be found in todays Herald (nicked from the Daily Mail) entitled, tellingly, Multi-vitamin pills ‘a waste of money’ – study.

The study in question is the latest paper[1] to come from the Su.Vi.Max study, a well-known French double-blind clinical trail of over 12,000 men and women who took either a placebo or a multi-vitamin (C, E, Beta-carotene, Zinc and Selenium). The headline, of course, is not the actual conclusion of the study but the reiteration of a common vitamyth – the “waste of money” myth. The study concludes:

The perception that supplementation improves general well-being is not supported by this trial.

The idea that vitamins make you feel better is also a vitamyth. We already knew that. Any competent vitaminologist (scientist who studies, rather than peddles, vitamins) could have told you this. Exercise makes you stronger and fitter and energises you. Vitamins will not.

We can conclude from the headline that this will not be a balanced review of a vitamin study. Enter the Dietician.

Dietitians are notorious for demonizing vitamin supplementation. They are also very good at producing vitamyths.

Many users fall into the category of the ‘worried well’ – healthy adults who believe the pills will insure them against deadly illnesses – according to Catherine Collins, chief dietician at St George’s Hospital in London.

This is a favorite vitamyth for dietitians (and many doctors) – that only people who are neurotic about their health take vitamins. After a statement such as this we can expect plenty of “evidence shows” statements and we are not disappointed.

Two studies published last year suggested supplements could raise the risk of cancer.

One found pills containing vitamin E, ascorbic acid, beta-carotene, selenium and zinc increased the risk of malignant melanoma, the deadliest form of skin cancer, four-fold.

The other discovered women on a daily multi-vitamin pill increased their risk of breast cancer by up to 20 per cent.

The first finding[2] is from an earlier paper from the same Su.Vi.Max study. The actual incidence of melanoma in France is very low so the numbers were very small, despite the large initial sample. The power of the study is therefore questionable. In addition, the Su.Vi.Max study used supplements with beta carotene, which has been implicated in previous studies with increased incidence of other forms of cancer. A recent large, prospective cohort study[3] found no link at all, casting this finding into doubt.

The second paper is presumably the Swedish Cohort study[4]. As far as I am aware, this is the only study that has shown any sort of link between multivitamin use and breast cancer and a recent meta-analysis[5] concluded that there is no evidence of a correlation. The cancer-producing potential of vitamins appears to be unconvincing and yet another vitamyth.

Not content with quoting the cancer-scare myth, the writer of the article cannot even get basic facts in the research paper correct:

In the supplement group, 30.5 per cent of patients had suffered a major health ‘event’, such as cancer or heart disease.

In the placebo group, the rate was 30.4 per cent.

30% suffered a major health event in 6 years? Was the cohort group entirely geriatric? The study, of course says that 30% suffered a “health event” (something that worried them about their health), not that 30% had cancer. In fact the numbers of cancers and serious heart events were again too small to have real statistical power. These figures were taken from the original study. The current paper focused solely on quality of life issues.

Ironically, the original Su.Vi.Max trial found that multivitamin supplementation decreased overall cancer risk and overall mortality in men (but not women) – an effect that wore off after supplementation ended[6], indicating that it was, indeed, due to the vitamins. It also showed improved cognition skills in both men and women who took supplements[7].

Vitamins are not as useless, nor are they as magical, as the vitamyth makers would have us believe. They certainly come a distant second to a good lifestyle of exercise and a varied diet and they are no kind of magic bullet. On the other hand, they are surely not the “waste of money” the ill-informed purport them to be.

Take them by all means. Take them in good health.

References:

1. Serge Briançon, Stéphanie Boini, Sandrine Bertrais, Francis Guillemin, Pilar Galan, and Serge Hercberg, Long-term antioxidant supplementation has no effect on health-related quality of life: The randomized, double-blind, placebo-controlled, primary prevention SU.VI.MAX trial Int. J. Epidemiol. (2011) 40(6): 1605-1616

2. Hercberg S, Ezzedine K, Guinot C, Preziosi P, Galan P, Bertrais S, Estaquio C, Briançon S, Favier A, Latreille J, Malvy D.  Antioxidant supplementation increases the risk of skin cancers in women but not in men. J Nutr. 2007 Sep;137(9):2098-105.

3. Antioxidant Supplementation and Risk of Incident Melanomas: Results from a Large Prospective Cohort Study

4. Multivitamin use and breast cancer incidence in a prospective cohort of Swedish women

5. Chan AL, Leung HW, Wang SF. Multivitamin supplement use and risk of breast cancer: a meta-analysis. Ann Pharmacother. 2011 Apr;45(4):476-84.

6. Hercberg S, Kesse-Guyot E, Druesne-Pecollo N, Touvier M, Favier A, Latino-Martel P, Briançon S, Galan P. Incidence of cancers, ischemic cardiovascular diseases and mortality during 5-year follow-up after stopping antioxidant vitamins and minerals supplements: a postintervention follow-up in the SU.VI.MAX Study. Int J Cancer. 2010 Oct 15;127(8):1875-81.

7. Kesse-Guyot E, Fezeu L, Jeandel C, Ferry M, Andreeva V, Amieva H, Hercberg S, Galan P. French adults’ cognitive performance after daily supplementation with antioxidant vitamins and minerals at nutritional doses: a post hoc analysis of the Supplementation in Vitamins and Mineral Antioxidants (SU.VI.MAX) trial. Am J Clin Nutr. 2011 Sep;94(3):892-9.

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