There is no evidence that people who take antioxidants like vitamins A and E will enjoy prolonged lives and some may actually be harmed, research has suggested.
A review of 67 studies involving more than 230,000 people found "no convincing evidence" that antioxidant supplements cut the risk of dying.
"Even more, beta-carotene, vitamin A, and vitamin E seem to increase mortality," the experts wrote.
The review, published by The Cochrane Collaboration, involved trials on beta-carotene, vitamin A, vitamin C, vitamin E, and selenium.
The experts noted that the studies involved different doses of each antioxidant.
For example, the beta-carotene dose ranged from 1.2mg to 50mg daily, with an average of 18mg, while vitamin C ranged from 60mg to 2000mg daily, with an average of 497mg.
People taking part in the trials were either healthy (and were taking part in primary prevention trials) or had any sort of disease (and were taking part in secondary prevention trials).
A total of 232,550 people were included across all the trials. Forty-seven trials included 180,938 people and had a low risk of bias.
In these trials with a low risk of bias, the "antioxidant supplements significantly increased mortality", the authors wrote.
When the different antioxidants were assessed separately and low risk of bias trials were included and selenium excluded, vitamin A was linked to a 16% increased risk of dying, beta-carotene to a 7% increased risk and vitamin E to a 4% increased risk.