Vitamins taken by around a third of the population do not extend life and may even cause premature death, according to a respected group of international scientists.
After reviewing 67 studies involving more than 230,000 men and women, the experts say there is no convincing evidence that taking supplements of the antioxidant vitamins A, C and E can make you healthier.
The alarming findings, published today, will shock Britons who spend £333million a year on supplements.
Forty per cent of women and 30 per cent of men take a vitamin pill each day.
The review involved trials on beta-carotene, vitamin A, vitamin C, vitamin E and selenium.
It says in-depth analysis of the different trials does not support the idea that vitamins extend lifespan.
'Even more, beta-carotene, vitamin A, and vitamin E seem to increase mortality,' says the review.
Vitamin A was linked to a 16 per cent increase in mortality, beta-carotene - the pigment found in carrots, tomatoes and broccoli which the body converts into vitamin A - to a 7 per cent increase and vitamin E to a 4 per cent increase. However, there was no significant detrimental effect caused by vitamin C.
'There was no evidence to support either healthy people using antioxidants to prevent disease or for sick people to take them to get better,' said the review.
It said more research was needed on vitamin C and selenium.
Antioxidants are used by the body as protection against free radicals, which are molecules produced during normal metabolism.
These can damage the body if they flourish in an uncontrolled way as a result of illness, overexposure to toxins or ageing.
It is thought antioxidants such as vitamin C confer health benefits by 'grabbing' or neutralising free radicals, and many people take them as health 'insurance'.
The theory behind using antioxidants is to combat oxidation - the chemical reaction that causes metals to rust - which in cells can damage DNA, thus raising the risk of cancer, other diseases and the changes associated with ageing.
Previous human and animal laboratory research suggested that boosting antioxidant levels in the body might extend life, but other studies produced neutral or even harmful results.
The review is published by the Cochrane Library, a publication of the Cochrane Collaboration, an international organisation which evaluates healthcare research.
Altogether 47 trials involving 180,938 people were classified as having a low risk of bias which showed 'antioxidant supplements significantly increased mortality'.
Goran Bjelakovic, who led the review at the Copenhagen University Hospital in Denmark, said: 'We could find no evidence to support taking antioxidant supplements to reduce the risk of dying earlier in healthy people or patients with various diseases.
'The findings of our review show that if anything, people in trial groups given the antioxidants beta-carotene, vitamin A, and vitamin E showed increased rates of mortality.
'There was no indication that vitamin C and selenium may have positive or negative effects. So, regarding these antioxidants, we need more data from randomised trials.
'The bottom line is that current evidence does not support the use of antioxidant supplements in the general healthy population or in patients with certain diseases.'
The review does not offer any biological explanation as to why supplements can cause harm, although it has been suggested that betacarotene, for example, might interfere with the body's use of fats.
There is no suggestion from the review that a healthy diet including plenty of vegetables and fruit - natural sources of antioxidants - is harmful.
The latest scare has infuriated many in the vitamins industry and nutritionists such as Patrick Holford who believe there is a campaign by the medical establishment to discredit their products and their role in optimising health.
Mr Holford said the review was 'a stitch-up' because all the studies were chosen strictly for reducing mortality, and not for the many advantages reported in other studies.
He said: 'The only way this review could produce the negative results was by finding reasons to exclude most of the positive studies, including all the positive ones on selenium.'
Although the authors claimed to be assessing antioxidant supplements for the prevention of mortality, they excluded all studies - 405 of them - which reported no deaths.
Mr Holford said: 'Antioxidants are not meant to be magic bullets and should not be expected to undo a lifetime of unhealthy habits.
'But when used properly, in combination with eating a healthy diet full of fruit and vegetables, getting plenty of exercise and not smoking, antioxidant supplements can play an important role in maintaining and promoting overall health.
'I take, and will continue to take an all-round antioxidant supplementing containing these nutrients as well as CoQ10, lipoic acid and resveratrol - the "red wine" factor - and also eat a diet high in fruit and vegetables.'
Pamela Mason, of the industry-backed Health Supplements Information Service, said: 'Antioxidant vitamins, like any other vitamins, were never intended for the prevention of chronic disease and mortality.
'They are intended for health maintenance on the basis of their various physiological roles in the body and in the case of antioxidant vitamins, this does, in appropriate amounts, include a protective antioxidant effect in the body's tissues.
'These vitamins are essential for health and many people in the UK do not have an adequate intake.
'A vitamin supplement taken in recommended amounts can be beneficial for health, especially for those people whose intakes are poor.'