Too much of a good thing: the dangers of antioxidant supplements

WANT a healthy, disease-free life? Then eat plenty of fruit and vegetables.

It's the "mantra" for healthy living that we have heard countless times. And it's true. Fruit and vegetables contain high levels of antioxidants that help protect us from "free radicals", which are molecules generated by the body and can cause damage to our cells.

To combat these free radicals and keep ourselves healthy, we have to maintain a diet that offers sufficient antioxidants.

However, many people take this approach even further by consuming a variety of antioxidant supplements such as Vitamin A, E, beta carotene or selenium on a daily basis. They believe that these vitamin and mineral pills ensure good health and protection from diseases, including cancer.

But like with so many other things in life, too much of a good thing will lead to problems. Researchers are beginning to discover that long-term over consumption of certain dietary supplements actually result in the exact opposite of what consumers hope to gain.

Studies now suggest that a person may actually have an increased risk of certain cancers through long-term over supplementation.

Dr Tho Lye Mun, a consultant clinical oncologist at Beacon International Specialist Centre, believes that it's time we started re-thinking the need for supplements.

He says there is no evidence to date to show that these dietary supplements offer any additional health benefits.

In fact, research now shows that longterm over supplementation is harmful. Dr Tho explains that antioxidant supplements are different from naturally found antioxidants in food because they are of a very high concentration.

"We know that people who take six portions of fruit and vegetables a day get sufficient antioxidants. You don't need more than that and the best source of antioxidants is still natural food and not supplements."

Pill popping and cancer

Early this year, the results of a study by Dr Tim Byers from the University of Colorado Cancer Center in the United States, showed a clear link between cancer and supplements.

The study examined more than 300,000 people over a 20-year period and determined that certain supplements increased the risk of cancer. The results of the study drove home the point that taking high dose supplements over a long period is harmful.

Dr Tho says the study looked at the dietary habits of the people involved and whether or not they were taking supplements, and the conclusion was that those who did, had an increased risk of cancer.

Byers' study also determined that selenium was associated with skin cancer, Vitamin E with prostate cancer and folic acid, which is a type of Vitamin B with an increased risk of colon cancer.

Last year, another US based research group from the Fred Hutchinson Cancer Research Centre in Seattle, cautioned men against taking selenium and Vitamin E supplements.

They established that selenium supplements, when consumed by men with already high baseline levels of the mineral, increased the risk of aggressive, high grade cancer by 91 per cent while Vitamin E raised the risk of prostate cancer by 63 per cent.

Antioxidants have also been linked to lung cancer. Last year, a team of scientists from the University of Gothenburg, Sweden, reported that two antioxidants - Vitamin E and N-acetylcysteine (NAC) sped up the progression of lung cancer. Their results were published in the journal called Science, Translational Medicine.

An earlier study, published in 1994 in the New England Journal of Medicine, also found that male smokers who took large, daily doses of beta-carotene supplements had an increased risk of developing lung cancer.

Seeking balance

Dr Tho says while free radicals have always been presumed to attack good cells, they are also helpful in attacking cancer cells and preventing them from growing or even existing.

As a result, if we overly consume antioxidants, the free radicals have less effectiveness over cancer cells. "In everything, there must be a balance. We want adequate protection from free radicals but we cannot completely go the other way either."

But the reality is that many people worldwide, including a large number of Malaysians, are convinced that dietary supplements are necessary and offer protective benefits.

Dr Tho says these are usually consumers who are very concerned about their health and want a guarantee or "insurance" for good health.

They want to take control of their health and believe that consuming supplements is the way to go. He explains that while short-term supplementation such as taking Vitamin C for a cold is not harmful, long-term over supplementation is worrying.

"There are no shortcuts to good health and popping a pill isn't going to solve the problem."

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