The Efficacy and Safety of Multivitamin and Mineral Supplement Use To Prevent Cancer and Chronic Disease in Adults: A Systematic Review for a National Institutes of Health State-of-the-Science Conference

5 September 2006 | Volume 145 Issue 5

Background: Multivitamin and mineral supplements are the most commonly used dietary supplements in the United States.

Purpose: To synthesize studies on the efficacy and safety of multivitamin/mineral supplement use in primary prevention of cancer and chronic disease in the general population.

Data Sources: English-language literature search of the MEDLINE, EMBASE, and Cochrane databases through February 2006 and hand-searching of pertinent journals and articles.

Study Selection: Randomized, controlled trials in adults were reviewed to assess efficacy, and randomized, controlled trials and observational studies in adults or children were reviewed to assess safety.

Data Extraction: Paired reviewers extracted data and independently assessed study quality.

Data Synthesis: 12 articles from 5 randomized, controlled trials that assessed efficacy and 8 articles from 4 randomized, controlled trials and 3 case reports on adverse effects were identified. Study quality was rated fair for the studies on cancer, cardiovascular disease, cataracts, or age-related macular degeneration and poor for the studies on hypertension. In a poorly nourished Chinese population, combined supplementation with ß-carotene, -tocopherol, and selenium reduced the incidence of and mortality rate from gastric cancer and the overall mortality rate from cancer by 13% to 21%. In a French trial, combined supplementation with vitamin C, vitamin E, ß-carotene, selenium, and zinc reduced the rate of cancer by 31% in men but not in women. Multivitamin and mineral supplements had no significant effect on cardiovascular disease or cataracts, except that combined ß-carotene, selenium, -tocopherol, retinol, and zinc supplementation reduced the mortality rate from stroke by 29% in the Linxian study and that a combination of 7 vitamins and minerals stabilized visual acuity loss in a small trial. Combined zinc and antioxidants slowed the progression of advanced age-related macular degeneration in high-risk persons. No consistent adverse effects of multivitamin and mineral supplements were evident.

Limitations: Only randomized, controlled trials were considered for efficacy assessment. Special nutritional needs, such as use of folic acid by pregnant women to prevent birth defects, were not addressed. Findings may not apply to use of commercial multivitamin supplements by the general U.S. population.

Conclusions: Evidence is insufficient to support the presence or absence of benefits from use of multivitamin and mineral supplements to prevent cancer and chronic disease.

Author and Article Information

From the Bloomberg School of Public Health and the School of Medicine, Johns Hopkins University, Baltimore, Maryland.

Acknowledgments: The authors thank Steven Bressler for assistance with the literature searching and database management; Gabriel Lai, Karran Phillips, Konstantinos K. Tsilidis, and Amina Chaudhry for assistance with article reviewing and data entry; and Brenda Zacharko for her editorial assistance.

Grant Support: The study was requested and funded by the National Institutes of Health and conducted by the Johns Hopkins Evidence-based Practice Center, under contract no. 290-02-0018 to the Agency for Healthcare Research and Quality.

Potential Financial Conflicts of Interest: None disclosed.

Requests for Single Reprints: Han-Yao Huang, PhD, MPH, Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, 615 North Wolfe Street, E-6144, Baltimore, MD 21205-2223; e-mail, hyhuang{at}jhsph.edu.

Current Author Addresses: Dr. Huang: Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, 615 North Wolfe Street, E-6144, Baltimore, MD 21205-2223.

Dr. Caballero: Department of International Health, Bloomberg School of Public Health, Johns Hopkins University, 615 North Wolfe Street, E2041, Baltimore, MD 21205.

Dr. Chang: Department of Medicine, Johns Hopkins School of Medicine, 1830 Building, Room 8040, 600 North Wolfe Street, Baltimore, MD 21287-1824.

Dr. Alberg: Hollings Cancer Center, Medical University of South Carolina, 86 Jonathan Lucas Street, P.O. Box 250955, Charleston, SC 29425.

Dr. Semba: Department of Ophthalmology, Johns Hopkins School of Medicine, 550 North Broadway, Suite 700, Baltimore, MD 21205.

Dr. Schneyer: Division of Endocrinology Johns Hopkins University School of Medicine, 1830 Building, Room 333, 600 North Wolfe Street, Baltimore, MD 21287.

Ms. Wilson: Evidence-based Practice Center, Bloomberg School of Public Health, Johns Hopkins University, 1830 East Monument Street, Room 8061, Baltimore, MD 21287.

Mr. Cheng: Department of Epidemiology, P.O. Box 1032, Bloomberg School of Public Health, Johns Hopkins University, 615 North Wolfe Street, Baltimore, MD 21205.

Mr. Vassy: Bloomberg School of Public Health, Johns Hopkins University, 615 North Wolfe Street, Baltimore, MD.

Dr. Prokopowicz: Department of Medicine, Johns Hopkins School of Medicine, 601 North Caroline Street, JHOC 7157, Baltimore, MD 21287.

Mr. Barnes: Evidence-based Practice Center, Bloomberg School of Public Health, Johns Hopkins University, 1830 East Monument Street, Room 8063, Baltimore, MD 21287.

Dr. Bass: Evidence-based Practice Center, Bloomberg School of Public Health, Johns Hopkins University, 1830 East Monument Street, Room 8068, Baltimore, MD 21287.