Ask a silly question – vitamins & minerals – good or bad or indifferent?
In light of the recent headlines I was going to write a lovely blog tomorrow to put a more balanced perspective but BioCare have beaten me to it! So here is their reply – and a lot more scientific than the Annals of Internal Medicine! I wonder who paid for their study?!
Ask a silly Question…..
In a rather melodramatic editorial in the Annals of Internal Medicine titled ‘Enough Is Enough: Stop Wasting Money on Vitamin and Mineral Supplements’, the authors claim that multivitamin supplements show no evidence of a beneficial effect on all-cause mortality, cardiovascular disease, cancer, or cognitive performance1 . They also re-issued outdated studies that appear to demonstrate that beta-carotene, vitamin E, and possibly high doses of vitamin A supplements increase mortality.
It’s difficult to prove anything when asking such a silly question. Neither their variables (just what exactly is a multivitamin, which one, how good, what levels etc.?), nor trying to cover such broad outcomes, offer any kind of clarity. Not to mention the methodological flaws in such epidemiological studies such as the huge non-compliance admitted in the Gervasio cardiovascular study2 or that the vitamin levels may have been too low (or used with the wrong population, since their control group showed no evidence of cognitive decline!) in the Grodstein cognitive study3. And, because they showed no effect, then all vitamins and minerals were swiftly classified as equally useless.
Of course if we conduct a more balanced literature search you start to see some alternative findings really rather quickly. The recent findings of the Women’s Health Initiative (WHI) showed that older women who developed invasive breast cancer while taking multivitamin supplements had a 30% lower rate of breast cancer mortality than women who did not take supplements. Maybe the authors didn’t intend to scare women with breast cancer from taking supplements to increase their survival rate, but you wouldn’t have thought so from the rhetoric and the headlines. One of the key studies they quote in the Annals article, the Physicians’ Health Study II, actually found benefits in reducing the risk of cancer and cataracts. In another study, multivitamin intervention significantly improved physical recovery and psychological parameters in over-trained army recruits4. As far as cognition is concerned, a more specific study looked at supplementation in people with high homocysteine levels of Vitamin B6, B12 and folic acid and found a reduction in rate of brain shrinkage, and consequently lower risk for dementia5.
So are ‘these vitamins’ dangerous? Oddly the studies quoted in the Annals editorial don’t show this at all. They show no effect in ether direction, so the authors are reliant on ‘wheeling out’ a couple of older, discredited studies to back up this claim. The JAMA 2007 meta-analysis6 that found an increase in mortality associated with beta carotene, vitamin E and vitamin A has since been re-examined showing an overwhelmingly null or positive effect7. The infamous Finnish antioxidant study showing increase in cancer rates among male smokers taking beta-carotene8 was also re-examined taking into account total antioxidant intake, revealing that more total antioxidants resulted in fewer cancers9. A vitamin E meta-analysis showing increases in mortality10 was followed up with a major review in the American Journal of Clinical Nutrition re-examining the totality of safety data and concluding that doses of up to 1,600 IU daily are safe11.
In fact, there’s lots of good evidence coming out every day that shows the benefits of targeted supplements on specific health outcomes. Vitamin D reducing mortality rates in elderly women who were deficient is just one example12.
In the end this editorial is based on data and studies that are not especially relevant. In a world where anyone who understands nutrition and health is moving towards more individualised nutrition, looking at studies where everyone took the same ‘category’ of product (not even the same product) produces meaningless results. So we agree that enough is enough and it’s time to exchange bad science for good.
1Guallar et al Enough Is Enough: Stop Wasting Money on Vitamin and Mineral Supplements
17 December 2013, Vol 159, No. 12>
2Gervasio et al Oral High-Dose Multivitamins and Minerals After Myocardial Infarction: A Randomized Trial Ann Intern Med. 2013;159(12):797-805-805.
3Grodstein, Long-Term Multivitamin Supplementation and Cognitive Function in Men: A Randomized Trial. Ann Intern Med. 2013;159(12):806-814-814.
4Li X, et al. Effects of a Multivitamin/multimineral Supplement on Young Males with Physical Overtraining: A Placebo-controlled, Randomized, Double-blinded Cross-over Trial. Biomed Environ Sci. 2013 Jul;26(7):599-604.
5Smith, de Jager et al Cognitive and clinical outcomes of homocysteine-lowering B-vitamin treatment in mild cognitive impairment: a randomized controlled trial. Int J Geriatr Psychiatry (2012) 27: 592-600.
6Bjelakovik Mortality in randomized trials of antioxidant supplements for primary and secondary prevention: systematic review and meta-analysis. JAMA. 2007 Feb 28;297(8):842-57.
7Biesalski Reexamination of a Meta-Analysis of the Effect of Antioxidant Supplementation on Mortality and Health in Randomized Trials Nutrients 2010, 2(9), 929-949.
8N Engl J Med. 1994 Apr 14;330(15):1029–35. The effect of vitamin E and beta carotene on the incidence of lung cancer and other cancers in male smokers. The Alpha-Tocopherol, Beta Carotene Cancer Prevention Study Group.
9July 2004 American Journal of Epidemiology Development of a Comprehensive Dietary Antioxidant Index and Application to Lung Cancer Risk in a Cohort of Male Smokers. Margaret E. Wright, Susan T. Mayne, Rachael Z. Stolzenberg-Solomon, Zhaohai Li, Pirjo Pietinen, Philip R. Taylor, Jarmo Virtamo and Demetrius Albanes
10Edgar R. Miller, III, MD, PhD; et al. High-dose vitamin E supplementation may increase all-cause mortality, a dose response meta-analysis of randomized trials. Annals of Internal Medicine: Online: Nov. 10, 2004: Print: 4 January 2005 | Volume 142 Issue 1
11John N Hathcock, et al. REVIEW ARTICLE: Vita- mins E and C are safe across a broad range of intakes. American Journal of Clinical Nutrition, Vol. 81, No. 4, 736–745, April 2005.
12Bjelakovic et al Vitamin D supplementation for prevention of mortality in adults. Cochrane Database Syst Rev. 2011 Jul 6;(7):CD007470. doi: 10.1002/14651858.CD007470.pub2.