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Antioxidants don't help you live longer

2007-06-06 10:52:40

By CARLA K. JOHNSON, Associated Press Writer Tue Feb 27 2007, 11:13 PM ET

CHICAGO - Antioxidant vitamins taken by tens of millions of people around the

world won't lead to a longer life, according to an analysis of dozens of

studies that adds to evidence questioning the value of the popular supplements.

The large review of separate studies on thousands of people found no long-life

benefit from vitamins A, E and C and beta carotene and selenium.

However, some experts said it's too early to toss out all vitamin pills or

the possibility that they may have some health benefits. Others said the study

supports the theory that antioxidants work best when they are consumed in food

rather than pills.

An estimated 80 million to 160 million people take antioxidants in North

America and Europe, about 10 to 20 percent of adults, the study's authors said.

And last year, Americans spent $2.3 billion on nutritional supplements and

vitamins at grocery stores, drug stores and retail outlets, excluding Wal-Mart,

according to Information Resources Inc., which tracks sales.

The new study, appearing in Wednesday's

Journal of the American Medical Association, was led by the Cochrane

Hepato-Biliary Group at Copenhagen University Hospital in Denmark. The Cochrane

organization is a respected international network of experts that does

systematic reviews of scientific evidence on health interventions.

For the new report on antioxidants, the researchers first analyzed 68 studies

involving 232,606 people and found no significant effect on mortality neither

good nor bad linked to taking antioxidants.

When they eliminated the lower-quality studies and looked only at the most

trustworthy ones, they actually found a higher risk of death for people taking

vitamins: 4 percent for those taking vitamin E, 7 percent for beta carotene and

16 percent for vitamin A. The actual cause of death in most studies was

unknown, however.

Those findings are based on an analysis of 47 studies involving 180,938 people

who were randomly assigned to get real vitamins or dummy pills. Some involved

superdoses far exceeding the recommended daily amount of the compounds; others

involved normal doses.

Some experts who reviewed the research were dismissive of the increased death

risk and the analysis overall, saying it pooled studies that were too diverse.

However, the study's senior author, Dr. Christian Gluud of Copenhagen

University Hospital, said, "The main message is that prevention by beta

carotene, vitamin A and vitamin E cannot be recommended. These three

antioxidant supplements may increase mortality."

Gluud said most of the studies didn't reveal why those taking supplements died,

but "in all likelihood, what they died from is what people normally die from,

maybe accelerated artherosclerosis, maybe cancer."

Antioxidant supplements have been tested repeatedly by many clinical trials

with no consistent clear evidence for their health effects, Gluud said.

"We have had this huge industry really wanting to demonstrate an intervention

effect that has gone to lengths to do so," Gluud said. "Sadly enough for the

industry, and for us as consumers, it has failed to do so."

Preliminary studies suggested antioxidants might block the heart-damaging

effects of oxygen on arteries and the cell damage that might encourage some

kinds of cancer.

But some researchers now believe antioxidants work only when they are in food,

or that people who eat vitamin-rich food are healthier simply because they take

better care of themselves. And beta carotene supplements have been found to

increase lung cancer risk in smokers.

Meir Stampfer, professor of nutrition and epidemiology at the Harvard School of

Public Health, said the new analysis hasn't discouraged him from taking his

vitamins.

Stampfer said the studies were too diverse to pool together because they looked

at various combinations and doses of antioxidants tested in different groups of

people. The trials ranged from a three-month study of 109 elderly nursing home

residents to a 12-year study of 22,071 male doctors.

"This study does not advance our understanding, and could easily lead to

misinterpretation of the data," said Stampfer, who was not connected to the new

report.

The complaints were echoed by Andrew Shao, a scientist at the Council for

Responsible Nutrition, a supplement trade association.

"Only when they included and excluded certain trials were they able to find

this alleged increase in mortality, which they themselves can't explain," Shao

said. "There is plenty of data out there that show regular use of antioxidant

supplements help to maintain health."

Donald Berry, chairman of the department of biostatistics at the University of

Texas M.D. Anderson Cancer Center, said the analysis persuades him antioxidants

have no measurable health benefits, but he disagrees with the researchers'

finding of an increase risk of dying.

"There are so many choices you can make when you're doing these analyses," he

said.

Alice Lichtenstein, a professor of nutrition science and policy at Tufts

University who was not involved with the research, said the study's main

message is: "Rely on food to get your nutrients."