Does a Mutli Vitamin Help

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http://www.annals.org/cgi/content/full/145/5/372

NIH CONFERENCE

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

Han-Yao Huang, PhD, MPH; Caballero, MD, PhD;

Chang, MD; J. Alberg, PhD, MPH;

D. Semba, MD, MPH; R. Schneyer, MD;

F. , MSc; Ting-Yuan Cheng, MSc;

Vassy, MPH; Prokopowicz, MD, MPH; J.

, II, BA; and B. Bass, MD, MPH

5 September 2006 | Volume 145 Issue 5 | Pages 372-385

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 prove the

presence or absence of benefits from use of

multivitamin and mineral supplements to prevent cancer

and chronic disease.