Copenhagen/Stockholm - Researchers at Copenhagen University have queried the benefits of vitamin supplements that millions of people often take in pill form. They reviewed 67 studies totalling some 232,000 subjects who used supplements like vitamin A, vitamin C, vitamin E, beta-carotene and selenium or were given a placebo.
The conclusions suggested that "overall, the antioxidant supplements did not seem to reduce mortality," said the 191-page review published by the Cochrane Collaboration.
The review included 21 trials with 169,000 healthy participants and 46 trials with "68,111 participants with various diseases" ranging from gastrointestinal and cardiovascular diseases to diseases linked to the glands and hormones.
The review was based on trials carried out in Asia, Australia, Europe and North and South America.
Vitamin E and C as well as beta-carotene are collectively known as antioxidants and proponents of daily such supplements believe they may protect body cells from oxidation.
However, the review suggested that vitamin A was linked to a 16 per cent increased mortality risk, vitamin E raised the mortality rate by 4 per cent while beta-carotene increased the risk by 7 per cent.
"We suspect that the antioxidants have caused an increase of cancer diseases and cardiovascular disease," review co-author Christian Gluud, professor at Copenhagen University Hospital, told Swedish daily Dagens Nyheter.
Gluud and co-author Goran Bjelakovic have for several years studied antioxidant supplements and published several reports on the topic.
They recommended "additional research on antioxidant supplements," adding that "evidence on vitamin C and selenium was not conclusive."
Antioxidants in fruits or vegetables were not assessed in the review.
More details of the study were available on the Cochrane Collaboration, a network that compiles and publishes data from other studies, on www.cochrane.org/.
