Multivitamins Fail to Protect Older Women from
Cancer, Heart Disease or Death
Some benefit from stress supplements with folic
acid and other B vitamins for lower heart attack risk
Feb. 11, 2009 – Older women looking for ways to
save money in this recession may want to drop multivitamins from their
shopping list. A gigantic study finds postmenopausal women who take
multivitamins appear to have the same risk of most common cancers,
cardiovascular disease or dying of any cause as women who do not take
multivitamin supplements.
About half of Americans use dietary supplements,
spending more than $20 billion per year on these products, according to
background information in the report in the February 9 issue of Archives
of Internal Medicine, one of the JAMA/Archives journals.
"The motivations for supplement use vary, but
common reasons include the belief that these preparations will prevent
chronic diseases, such as cancer and cardiovascular disease," the
authors write.
"These views are often fueled by product health
claims, consumer testimonials and an industry that is largely
unregulated owing to the 1994 Dietary Supplement and Health Education
Act." Scientific data supporting the benefits of supplements—including
multivitamins, the most commonly used supplements—are lacking.
Marian L. Neuhouser, Ph.D., of the Fred Hutchinson
Cancer Research Center, Seattle, and colleagues analyzed data from
participants in the Women's Health Initiative (WHI): 161,808 women from
three clinical trials testing hormone therapy, dietary modification and
vitamin D supplements and 93,676 women who were part of an observational
study.
The women enrolled in the WHI between 1993 and
1998; information about vitamin use was collected through interviews and
by supplement bottles brought to clinic visits.
A total of 41.5 percent of the participants used
multivitamins.
What were considered a “Multivitamin”
Multivitamins were grouped into 3 classifications
based on ingredients:
(1) multivitamins (alone) were
preparations with 10 or more vitamins and no minerals in which the
nutrient levels were at least 100% of US Recommended Dietary Allowance
(RDA);
(2) multivitamins with minerals were
preparations with 20 to 30 vitamins and minerals and nutrient levels of
100% or less of US RDA; and
(3) stress multisupplements were
preparations with higher doses (often >200% of US RDA) of several B
vitamins and often including large doses of vitamin C or selected
minerals, such as selenium or zinc.
Supplement mixtures with fewer than 10
components, such as B complex or antioxidant mixtures, were not
considered multivitamins.
The researchers found that through 2005 (a median or midpoint of eight years
of follow-up for the clinical trials and 7.9 years for the observational
study) the following occurred…
● 9,619 cases of breast, colorectal, endometrial,
renal, bladder, stomach, lung or ovarian cancer;
● 8,751 cardiovascular events, such as heart
attack and stroke; and
● 9,865 deaths were reported.
Analyses revealed no significant associations
between multivitamin use and the likelihood of developing cancer or
cardiovascular disease, or of dying.
"Risk estimates did not materially change when
stratified by class of multivitamins, with the exception of a possible
lower risk of myocardial infarction [heart attack] among users of
stress-type supplements,” the authors write.
“Many stress supplements include high doses of
folic acid and other B vitamins; previous studies have supported a
protective role for folic acid in relation to cardiovascular disease and
its antecedent risk factors.
"These results suggest that multivitamin use does
not confer meaningful benefit or harm in relation to cancer or
cardiovascular disease risk in postmenopausal women," the authors
conclude.
"Nutritional efforts should remain a principal
focus of chronic disease prevention, but without definitive results from
a randomized controlled trial, multivitamin supplements will not likely
play a major role in such prevention efforts."
Editor's Note: The WHI program is funded by the
National Heart, Lung and Blood Institute, National Institutes of Health,
U.S. Department of Health and Human Services.
>> Multivitamin/Mineral Supplements and Chronic
Disease Prevention 2006 - State-of-the-Science Conference Statement,
National Institutes of Health –
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Feb. 11, 2009 – Older women looking for ways to
save money in this recession may want to drop multivitamins from their
shopping list. A gigantic study finds postmenopausal women who take
multivitamins appear to have the same risk of most common cancers,
cardiovascular disease or dying of any cause as women who do not take
multivitamin supplements.