Many studies suggest that supplementary vitamins provide no benefits, and use increases
the risk of cancer, cardiovascular disease, and “all-cause” death rates. In his
book, Do You Believe in Magic? The Sense and Nonsense of Alternative Medicine,
Paul Offit, describes a series of major studies that evaluated the health effects of a
variety of vitamins and other supplements. He describes research that tested the
theory that antioxidants would be beneficial to health. The unexpected finding was
that antioxidants were often harmful. One study found that those taking vitamin E,
beta-carotene, or both, were more likely to die from lung cancer or heart disease
than those who didn’t take them. Another found that study subjects taking vitamin
A, beta-carotene, or both, were dying from cancer at a rate 28% higher and heart
disease at a rate 17% higher than those who didn’t take the vitamins.97 A large study
of people who took vitamins A, C, E, and beta-carotene found no evidence that antioxidants
could prevent intestinal cancers, rather they found that death rates were
6% higher in those taking vitamins.
Offit cites other studies that have found an
increased risk of death and heart failure associated with supplemental vitamin E.
He notes that “In 2007, researchers from the National Cancer Institute examined
11,000 men who did or didn’t take multivitamins. Those who took multivitamins
were twice as likely to die from advanced prostate cancer.”
A 2007 study published in the Journal of the American Medical Association assessed
mortality rates in randomized trials of antioxidant supplements. In 47 trials
involving 181,000 participants. Mortality was 5% higher among those using the
antioxidants vitamin A, beta-carotene, and vitamin E. The studies did not detect a
mortality effect of vitamin C or selenium. Offit’s summary of the evidence stated
that “In 2008, a review of all existing studies involving more than 230,000 people
who did or did not receive supplemental antioxidants found that vitamins increased
the risk of cancer and heart disease.”102 103
A January 2009 editorial in the Journal of the National Cancer Institute noted that
most studies of vitamins had shown no cancer benefits, but some had shown unexpected
harms. Two studies of beta-carotene found higher lung cancer rates, and
another study suggested a higher risk of precancerous polyps among users of folic
acid compared with those in a placebo group. And another study of 36,000 men
who took vitamin E, selenium, both, or neither found that those receiving vitamin E
had a 17% greater risk of prostate cancer.”
A study published in 2011 in the Archives of Internal Medicine assessed the use of
vitamin and mineral supplements in relation to total mortality in 38,772 older women
in the Iowa Women’s Health Study. Sixty-six percent of women participating in
the Iowa Women’s Health Study used at least one dietary supplement daily in 1986.
By 2004, the proportion had increased to 85%, with 27% of women using four or
more supplements.108 The Iowa study found that the use of multivitamins, vitamin
B6, folic acid, iron, magnesium, zinc, and copper were all associated with a 2% to
4% increased risk of death. The study authors concluded that “In older women,
several commonly used dietary vitamin and mineral supplements may be associated
with increased total mortality risk…”
This blog presents opinions and ideas and is intended to provide helpful general information. I am not engaged in rendering advice or services to the individual reader. The ideas, procedures and suggestions in that are presented are not in any way a substitute for the advice and care of the reader’s own physician or other medical professional based on the reader’s own individual conditions, symptoms or concerns. If the reader needs personal medical, health, dietary, exercise or other assistance or advice the reader should consult a physician and/or other qualified health professionals. The author specifically disclaims all responsibility for any injury, damage or loss that the reader may incur as a direct or indirect consequence of following any directions or suggestions given in this blog or participating in any programs described in this blog or in the book, The Building Blocks of Health––How to Optimize Your Health with a Lifestyle Checklist (available in print or downloaded at Amazon, Apple, Barnes and Noble and elsewhere). Copyright 2021 by J. Joseph Speidel
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