Antioxidant Supplements Up Death Risk
Study Shows No Benefit, Slightly Higher Death Risk for Antioxidant Supplements
Antioxidant Supplements and Death Risk continued...
Shao says it just isn't fair to study antioxidants in this way.
"What these authors have done is combine studies that are incredibly
dissimilar in all sorts of ways," he says. "These studies looked at
different nutrients at different doses at different durations with different
lengths of follow-up -- and in different populations, ranging from folks who
were incredibly healthy to people with cancer and other diseases."
Moreover, Shao says, the researchers looked only at studies in which people
died. That left out 405 clinical trials, which he says skews the results in
favor of death risk. And he points out that the researchers original 68 studies
did not show any harm from supplements.
"These questions cause one to step back and wonder if the findings are
relevant to the healthy population that uses these supplements to maintain
health and avoid chronic disease," Shao says. "That is a point they
don't make: that antioxidants are not used to treat cancer or heart disease.
They are used for disease prevention."
Edgar R. Miller III, MD, PhD, associate professor of medicine at Johns
Hopkins University, in 2004 analyzed clinical trials of vitamin E. He found
that high doses of vitamin E did more harm than good. Miller has high praise
for the Bjelakovic/Gluud study.
"This is a great study. It is the highest form of scientific
evidence," Miller tells WebMD. "I don't think that [Shao's] criticism
is legitimate. I argue this is the best technique to analyze all this
Gluud and Bjelakovic strongly disagree that they "cherry picked"
only studies that fit some preconceived conclusion. They point out that all of
their methods are "transparent" and open to public view.
"Anyone is welcome to criticize our research," Gluud says. "But
my question is, what is your evidence? I think the parties that want to sell or
use these antioxidant supplements in the dosages used in these trials, they
want [to see only] positive evidence that it works beneficially."
Advice to Consumers
Kathleen Zelman, MPH, RD, LD, is director of nutrition for WebMD. She
reviewed the Bjelakovic/Gluud study for this article.
"This is a very comprehensive, to-be-respected analysis. This isn't just
another study coming out," Zelman says. "The bottom line is that
antioxidant supplements are not a magic bullet for disease prevention. We hoped
maybe they were, but they are not."
If you are interested in protecting your health, Zelman says, pills aren't
"There is no single food or nutrient that is going to be the answer. The
secret really is lifestyle," she says. "And the most important things
about lifestyle are being at a healthy weight, being physically active, and
eating a healthy diet."
Shao says he's not persuaded to stop taking antioxidant supplements.