|Are Multivitamins a Waste of Money?
Making the rounds in the news again is the idea that multivitamin supplements are unnecessary for most people. Indeed, most studies have not shown any consistent benefit of taking multivitamin and mineral supplements for preventing chronic diseases, so this new research comes as no surprise. Similar to the previous analyses, no consistent evidence was found that vitamin and mineral supplements reduced the risk of cardiovascular events, cancer or premature death.1-3 However, micronutrient deficiencies are certainly detrimental to health, and it makes sense to avoid them. Insufficient intake of some vitamins is a risk factor for chronic diseases and can be quite common, especially in elderly people.4
What does the new research tell us about vitamin and mineral supplements?
The new analysis evaluated 26 studies aimed to test whether vitamin and mineral supplements had any preventive effects against cardiovascular disease, cancer or all-cause mortality in healthy people with no known nutrient deficiencies. Out of all of these studies, only two large, long-term (11-12 year follow up) multivitamin trials met the quality criteria to be included in the analysis. Out of those two, one trial was conducted only in men and used a conventional, commercial multivitamin, and the other included both men and women and used a supplement containing only five nutrients (vitamin C, vitamin E, beta-carotene, selenium and zinc).3,5 So the study actually evaluated only one trial of a commercial multivitamin. There were no differences between treatment and control groups for all-cause mortality or cardiovascular events; this is not surprising, since adding a multivitamin to a typical Western diet cannot be expected to substantially improve one’s health. Interestingly, the study of the commercial multivitamin in men found a slight (6 percent) decrease in cancer risk.
These mostly neutral results are likely due to the fact that any study on multivitamins is studying many different variables; there are some helpful components and some harmful components in conventional multivitamins. Most contain ingredients that are associated with health risks in supplement form, such as vitamin A, beta-carotene, vitamin E, folic acid and copper. Plus, these nutrients are abundant in plant foods; there is no risk of deficiency in someone who is eating healthfully, so there is no reason to supplement. It is well known that for all vitamins and minerals, there are health risks associated with too little, and with too much. (Learn more about potentially harmful supplemental nutrients in Multivitamins: Ingredients to Avoid.) News of potential increased cancer risk with beta-carotene supplements began to surface in the 1990s, and the pooled analysis showing that vitamin A, beta-carotene and vitamin E supplements were associated with a greater risk of mortality was published in 2008.6 In those years, has any major multivitamin company removed these nutrients? I don’t know of any. My line of multivitamins is the only one I am aware of that does not contain vitamin A, beta-carotene, folic acid and vitamin E; all scientifically documented cancer risks.
The new study confirmed some of these risks in its analysis of trials of supplementation with single or paired nutrients. Although there was no “consistent pattern of harm” overall, the authors noted harms in individual studies: for example, increases in melanoma and hip fracture risks in women taking multivitamins, an increase in hip fracture risk in those taking vitamin A and increased risk of lung cancer in those taking beta-carotene plus vitamin A.3
If the study on conventional multivitamins was continued for 20 to 30 years and included women, I expect that we would eventually see an increase in cancer risk, as was seen in a previous study of 35,000 Swedish women. After only 9 years of follow-up, the risk of breast cancer was 19 percent greater in the women taking multivitamins.7 Synthetic folic acid was likely the major contributor to this increase in risk as there is a growing link in science with folic acid increasing cancer.8-12
For excellent health, we should be getting the vast majority of our essential micronutrients from foods. The purpose of a multivitamin is not to counteract the ill effects of an unhealthy diet, it is to protect against deficiencies of essential micronutrients that may be difficult to obtain or absorb from our daily diet. Even with an ideal diet, certain nutrients may be lacking, such as vitamin B12, vitamin D, zinc and iodine. For example, vitamin B12 is scarce in plant foods, and our absorption becomes less efficient with age; about 20 percent of adults over the age of 60 are B12 deficient or insufficient.13 B12, therefore, is an appropriate nutrient to supplement. (To learn more, read “If I eat a healthy diet, do I really need a multivitamin?”)
Conventional multivitamins are more than a waste of money; in fact, they are likely to be harmful to your health. We must choose our supplements carefully. It is critical to only utilize supplements that have been designed without risky ingredients and avoids supplying excesses of things that can hurt when we take too much, such as copper, selenium, iron. The right supplements complement a healthful diet by filling potential nutritional gaps, while avoiding excess of any nutrient and excluding any ingredients that may cause harm. So supplements can be beneficial or harmful based on their design. To learn more, please visit Dr. Fuhrman's Multivitamin and Mineral Supplements, where I explain why I have chosen to include or exclude certain micronutrients from my line of supplements.
1. Prentice RL: Clinical trials and observational studies to assess the chronic disease benefits and risks of multivitamin-multimineral supplements. Am J Clin Nutr 2007;85:308S-313S.
2. NIH State-of-the-Science Conference Statement on Multivitamin/Mineral Supplements and Chronic Disease Prevention. NIH Consens State Sci Statements 2006;23:1-30.
3. Fortmann SP, Burda BU, Senger CA, et al: Vitamin and Mineral Supplements in the Primary Prevention of Cardiovascular Disease and Cancer: An Updated Systematic Evidence Review for the U.S. Preventive Services Task Force. Ann Intern Med 2013.
4. Fletcher RH, Fairfield KM: Vitamins for chronic disease prevention in adults: clinical applications. JAMA 2002;287:3127-3129.
5. Hercberg S, Galan P, Preziosi P, et al: The SU.VI.MAX Study: a randomized, placebo-controlled trial of the health effects of antioxidant vitamins and minerals. Arch Intern Med 2004;164:2335-2342.
6. Bjelakovic G, Nikolova D, Gluud LL, et al: Antioxidant supplements for prevention of mortality in healthy participants and patients with various diseases. Cochrane Database Syst Rev 2008:CD007176.
7. Larsson SC, Akesson A, Bergkvist L, et al: Multivitamin use and breast cancer incidence in a prospective cohort of Swedish women. Am J Clin Nutr 2010;91:1268-1272.
8. Charles D, Ness AR, Campbell D, et al: Taking folate in pregnancy and risk of maternal breast cancer. BMJ 2004;329:1375-1376.
9. Stolzenberg-Solomon RZ, Chang SC, Leitzmann MF, et al: Folate intake, alcohol use, and postmenopausal breast cancer risk in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. Am J Clin Nutr 2006;83:895-904.
10. Fife J, Raniga S, Hider PN, et al: Folic Acid Supplementation and Colorectal Cancer Risk; A Meta-analysis. Colorectal Dis 2009.
11. Ebbing M, Bonaa KH, Nygard O, et al: Cancer incidence and mortality after treatment with folic acid and vitamin B12. JAMA 2009;302:2119-2126.
12. Figueiredo JC, Grau MV, Haile RW, et al: Folic acid and risk of prostate cancer: results from a randomized clinical trial. J Natl Cancer Inst 2009;101:432-435.
13. Allen LH: How common is vitamin B-12 deficiency? Am J Clin Nutr 2009;89:693S-696S.