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Antioxidants: Setting the record straight

You've probably heard it said that red wine, tea, coffee and chocolate can reduce the risk of heart and blood vessel disease and slow down the ageing process because they contain antioxidants to combat the effects of 'free radicals' in the body. And there's no shortage of antioxidant supplements on the market today claiming similar benefits.

 

But can antioxidants really achieve these claims?

A free radical theory 

Free radicals are molecules produced naturally in the body that are believed to damage tissue. Researchers in the 1950s formulated the theory that damage done by too many free radicals in the body could be responsible for ageing and for increasing the risk of heart attacks and strokes.

The free radicals theory has remained mostly unchallenged for over 50 years, but more recent research has emerged that directly questions the strength of this theory.

Antioxidants: not a quick fix, according to research 

Researchers at the Institute of Healthy Ageing, University College London have questioned the theory that high levels of 'superoxide' free radicals increase the effect and speed of the ageing process.1

The researchers modified key genes involved in removing excess superoxide free radicals in roundworms (C. elegans). This particular roundworm is used in genetic research into ageing because it has a similar genetic structure to more complex organisms, and is also easy to control and change.

The researchers found that the gene changes didn't affect the mutated worms' lifespan.

"The results of this study challenge the popular belief that superoxides are a key factor in ageing and that mopping up free radicals is beneficial in slowing down the ageing process," said Dr Christine Bennett, Chair, Medical Advisory Panel, Bupa Australia.

As for the health benefits of antioxidants, in the 1990s a number of large population studies showed that people who ate more fruit and vegetables, which are rich sources of antioxidants, had a lower risk of heart disease and stroke. However, it's possible that these people also had healthier lifestyles in other ways — that is, it was unclear from these studies if antioxidants are directly responsible for lowering the heart disease and stroke risk since there were possibly other factors involved.

More recent medical research from 2008 looked at the results of 67 studies into antioxidant supplements and mortality. This independent review found no evidence to suggest that antioxidant supplements such as vitamin A, C and E, selenium and beta-carotene can decrease mortality.2

And in 2010, the National Heart Foundation of Australia weighed in with its own summary after reviewing 100 studies on antioxidants3 and found that drinking red wine or coffee, eating chocolate or using antioxidant supplements such as vitamin C and E doesn't prevent heart disease. In fact, there is some concern that high doses of vitamin E supplements could actually increase the risk of heart disease.

Instead of looking for the antioxidant quick fix, The Heart Foundation recommends the following to help reduce the risk of cardiovascular disease and to maintain good cardiovascular health:

  • consume at least two serves of fruit and five serves of vegetables every day
  • as part of a healthy, balanced diet, drink black or green tea, and opt for cocoa made from raw cocoa powder. Use reduced, low or no fat milk where possible to reduce energy and fat intake.3

The sum of this research is that antioxidants in food are not the quick fix many people are looking for, but there are healthy lifestyle choices you can make to look after your heart's health.

Key facts 

  • There is no compelling evidence to suggest antioxidants decrease mortality or slow ageing.
  • People who take antioxidant supplements should consider why they do, and if they could be getting the same nutritional benefits from a healthy diet.
  • Antioxidants can be found naturally in tea, citrus fruits, leafy greens, broccoli, mangoes, pumpkin, berries, among other foods.
  • Eating a balanced, healthy diet can reduce the risk of developing heart disease, cancer and type 2 diabetes.
  • A healthy, balanced diet should provide all the vitamins and minerals your body needs. Speak to your doctor or a registered dietitian for advice if you think you are not getting enough vitamins and minerals to support your health.4

Further information 

National Heart Foundation: Summary of evidence - Antioxidants in food, drinks and supplements for cardiovascular health

www.heartfoundation.org.au/

Sources 

  1. Doonan R, McElwee JJ, Matthijssens F et al. Against the oxidative damage theory of aging: superoxide dismutases protect against oxidative stress but have little or no effect on life span in Caenorhabditis elegans. Genes Dev. 2008; 22: 3236-41.
  2. Bjelakovic G, Nikolova D, Gluud LL, Simonetti RG, Gluud C. Antioxidant supplements for prevention of mortality in healthy participants and patients with various diseases. Cochrane Database Syst Rev. 2008; 2: CD007176.
  3. National Heart Foundation. Antioxidants in food, drinks and supplements for cardiovascular health. August 2010. [Accessed 21 June 2011] Available at: www.heartfoundation.org.au/information-for-professionals/food-professionals/Pages/guides-policies-position-statement.aspx
  4. Better Health Channel. Antioxidants. State Government of Victoria. [Last reviewed Mar 2010, accessed 21 June 2011] Available at: www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/Antioxidants

Last published: 30 July 2011

Disclaimer
This information has been developed and reviewed for Bupa by health professionals. To the best of their knowledge it is current and based on reputable sources of medical research. It should be used as a guide only and should not be relied upon as a substitute for professional medical or other health professional advice.

Bupa Australia Pty Ltd makes no warranties or representations regarding the completeness or accuracy of the information. Bupa Australia is not liable for any loss or damage you suffer arising out of the use of or reliance on the information. Except that which cannot be excluded by law. We recommend that you consult your doctor or other qualified health professional if you have questions or concerns about your health. For more details on how we produce our health content, visit the About our health information page.

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