Antioxidants – do they work

Get the Facts

  • Consumers don’t know that taking mega-vitamins can increase their risk of cancer and heart disease and shorten their lives.
  • Don’t take vitamins to get “anti-oxidants.” Instead of eating sugar and cheap, simple carbohydrates, eat complex carbohydrates.
  • Save your money and buy and eat some additional green vegetables.

Understand the Science

Bear with me! I am going to deal with antioxidants in a little more detail than vitamins, as everything these days promotes “healthy antioxidants” as if they are miracle workers.

Antioxidants are not necessarily vitamins, but some vitamins are antioxidants.

Anti-oxidation vs. oxidation has been billed as a contest between good and evil. It takes place in within cells in organelles called mitochondria, where the body converts food to energy — a process that requires oxygen (oxidation). One consequence of oxidation is the generation of atomic scavengers called free radicals (evil). Free radicals can damage DNA, cell membranes, and the lining of arteries. Not surprisingly, they’ve been linked to aging, cancer, and heart disease.

To neutralize free radicals, the body makes antioxidants (good). Antioxidants can also be found in fruits and vegetables, specifically in selenium, beta carotene, and vitamins A, C, and E. Some studies have shown that people who eat more fruits and vegetables have a lower incidence of cancer and heart disease, and they live longer. The logic is obvious. If fruits and vegetables contain antioxidants, and people who eat fruits and vegetables are healthier, then people who take supplemental antioxidants should also be healthier.

It hasn’t worked out that way. It could be that people who eat fruits and vegetables also eat less sugar and simple carbohydrates or any of the other multiple confounding behaviours. Antioxidants have always been questioned about their efficacy and their safety. Back in 1994, 29,000 Finnish men, all smokers, were given daily vitamin E, beta carotene (precursor to Vitamin A), both, or a placebo. The study found that those who took beta carotene for five to eight years were 18% more likely to die from lung cancer or heart disease.

Two years later, the same journal (NEJM), published another study on vitamin supplements. In it, 18,000 people who were at an increased risk of lung cancer because of asbestos exposure or smoking, received a combination of vitamin A and beta carotene, or a placebo. Investigators stopped the study when they found that the risk of death from lung cancer for those who took the vitamins was 46% higher. Then, in 2004, a review of 14 randomized trials for the Cochrane Database found that the supplemental vitamins A, C, E and beta carotene, and a mineral (selenium) taken to prevent intestinal cancers, actually increased mortality.

The National Cancer Council (USA) reported on the nine randomized controlled trials of dietary antioxidant supplements for cancer prevention. Overall, these nine randomized controlled clinical trials did not provide evidence that dietary antioxidant supplements are beneficial in primary cancer prevention. They say, though, that the lack of benefit in these trials can be explained by differences in the effects of the tested antioxidants when they are consumed as purified chemicals, as opposed to when they are consumed in foods, which contain complex mixtures of antioxidants, vitamins, and minerals.

The likely explanation is that free radicals aren’t as evil as advertised. In fact, people need them to kill bacteria and eliminate new cancer cells. And when people take large doses of antioxidants in the form of supplemental vitamins, the balance between free radical production and destruction might tip too much in one direction, causing an unnatural state where the immune system is less able to kill harmful invaders. Researchers call this the antioxidant paradox. Because studies of large doses of supplemental antioxidants haven’t clearly supported their use, respected organizations responsible for the public’s health do not recommend them for otherwise healthy people. But that is not the case for the commercial interests.

Back in 1972, concerned that people were consuming larger and larger quantities of vitamins, the USA FDA announced a plan to regulate vitamin supplements containing more than 150% of the recommended daily allowance. Vitamin makers had to prove that the “mega vitamins” were safe before selling them. Not surprisingly, the vitamin industry saw this as a threat, and set out to destroy the bill. Speaking in support of the bill, the lawyer for the Consumers Union set eight cantaloupes in front of her, and she said, “You would need to eat eight cantaloupes, a good source of vitamin C, to take in barely 1000 milligrams of vitamin C. But just these two little pills, easy to swallow, contain the same amount.” She warned that if the legislation passed, “One tablet would contain as much vitamin C as all of these cantaloupes, or even twice, thrice, or 20 times that amount. And there would be no protective satiety level.” But the bill passed and now anyone can sell multivitamins and call them good. The only prohibition is against claiming specific health benefits such as a cure. In looking at the advertisements on TV and the internet using celebrities and sports-people the claims for health benefits are pretty strong, and regulatory authorities seem to turn a blind eye to their claims.


Before researching the research, I thought that antioxidants were a little over-hyped but generally ineffective. We can see now that if you want to run the risk of increased cancer, take anti-oxidants. Eating some fruit and vegetables (note: fruit juice is not fruit) will reduce your weight and improve your health.

It seems like this claim for health from consuming antioxidants has no evidence. This is not a book on household budgeting, but for me any money spent on this sort of stuff is a complete waste of money. I’d rather give the money for clean water projects in Africa, or some other charity. At least it will do some good rather than line the pockets of the antioxidant companies.

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