Multivitamins, available in tablets, powders, liquids, and other forms, are intended to supplement a diet with vitamins, dietary minerals, and other nutritional elements.

They generally contain ten to 30 different types of vitamins and minerals. Many multivitamin products contain many of the following ingredients: A, B₁, B₂, B₃, B₅ (pantothenate), B₆, betacarotene, borate(s), C, calcium, chromium, folic acid (B₉), B₁₂, D₃, E, H (biotin), iron, K₁, magnesium, manganese, molybdenum, potassium iodide, selenomethionine, and zinc.

In the United States, multivitamins are the most popular dietary supplement sold to the public.

Consequently, a group of U.S. researchers decided to see if there was a direct correlation (tha tis, the use of multivitamins reduces the risk to certain cancers and diseases) between multivitamin use and the risk of cancer, cardiovascular disease (CVD), and mortality (death) in one group of people: postmenopausal women.

A wide range of ethnic backgrounds were studied within the women studied, including American Indian, Asian, black, Hispanic, and white.

The authors of the U.S. study, whose results “Multivitamin Use and Risk of Cancer and Cardiovascular Disease in the Women's Health Initiative Cohorts” were published in the Archives of Internal Medicine (2009;169(3):294-304), studied 161,808 women between the years of 1993 and 1998.

Page two contains the results of the study involving multivitams and the health of postmenopausal women (women living after the end of menstruation, usually after the ages of 45 to 50 years).

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The authors of the study are Marian L. Neuhouser, Sylvia Wassertheil-Smoller, Cynthia Thomson, Aaron Aragaki, Garnet L. Anderson, JoAnn E. Manson, Ruth E. Patterson, Thomas E. Rohan, Linda van Horn, James M. Shikany, Asha Thomas, Andrea LaCroix, and Ross L. Prentice.

The study was conducted with the help “from the Women’s Health Initiative clinical trials” (68,132 women) that involved three “overlapping trials of hormone therapy, dietary modification, and calcium and vitamin D supplements” or “an observational study” (93,676 women).

Data was collected on multivitamin use at a “baseline” time and then at “follow-up time points” over about an eight year period, ending in 2005.

The researchers looked for incidences of “cancers of the breast (invasive), colon/rectum, endometrium, kidney, bladder, stomach, ovary, and lung; CVD (myocardial infarction, stroke, and venous thromboembolism); and total mortality.”

Their data found:

(1) 41.5% of the women participating in the study used multivitamins.

(2) 9,619 cases of breast, colorectal, endometrial, renal, bladder, stomach, lung, or ovarian cancer were found.

(3) 8,751 cases of CVD events were found.

(4) 9,865 deaths occurred.

Of those women using multivitamins, it was found that those women were more likely to:

(1) exercise

(2) be white in ethnicity

(3) weigh less; that is, have a lower body mass index (BMI)

(4) live in the western portion of the United States

(5) be college-educated.

Page three provides conclusions from the authors of the study.

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Based on this data, the researchers concluded that there was “no association of multivitamin use with risk of cancer.”

Specifically, they found that the use of multivitamins for postmenopausal women did not reduce the risk for breast cancer, colorectal cancer, endometrial cancer, lung cancer, ovarian cancer, CVD [myocardial infarction (heart attack), stroke, venous thromboembolism (blood clot in veins)], and mortality (death).

However, they did find that the women (3,741 within the study) who took stress multivitamins, which are made specifically with larger doses of several B vitamins and Vitamin C, were 25% less likely to have a heart attack (myocardial infarction).

There were no other (relevant statistical) correlations between multivitamins and reduced risk from any of the studied diseases or conditions.

They stated in the abstract to their paper, “… the Women's Health Initiative study provided convincing evidence that multivitamin use has little or no influence on the risk of common cancers, CVD, or total mortality in postmenopausal women."

The authors are associated with the following organizations:

Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington (Neuhouser, Anderson, Patterson, LaCroix, Prentice, and Aragaki)

Department of Epidemiology and Preventive Medicine, Albert Einstein College of Medicine, New York, New York (Wassertheil-Smoller and Rohan)

Department of Nutritional Sciences, University of Arizona, Tucson (Thomson)

Division of Preventive Medicine, Harvard Medical School, Boston, Massachusetts (Manson)

Amylin Pharmaceuticals, Inc, San Diego, California (Patterson)

Department of Preventive Medicine, Northwestern University, Chicago, Illinois (van Horn)

Division of Preventive Medicine, University of Alabama at Birmingham (Shikany)

Medstar Research Institute, Washington, DC (Thomas).

Learn more about multivitamins at the Office of Dietary Supplements (U.S. National Institutes of Health).