What are free radicals?

Inside the cells in your body, many chemical reactions take place. Sometimes, by-products known as free radicals form.

Free radicals have a bad reputation, but they’re not all bad. Some are used by your body’s immune system to attack viruses or bacteria.

But some free radicals can damage cells. Others might contribute to health problems such as heart disease, some cancers and degeneration of the macula in the eye.

What are antioxidants and what do they do?

Antioxidants are substances that can neutralise free radicals in your body. They can stop them damaging your health.

The best known ones are vitamins A, C and E, beta-carotene, lutein, lycopene and selenium. Your body also produces its own antioxidants.

Antioxidants became prominent 20 years ago, because research suggested they would be able to prevent heart disease and many other chronic conditions. This research led many people to start taking antioxidant supplements.

Should I get my antioxidants in food or supplements?

The answer is food. You’re better off getting all the nutrients you need, including antioxidants, from healthy foods rather than from supplements.

For one thing, supplements seem to be less effective than healthy foods in combating heart disease and some cancers. People who eat a healthy diet generally have healthy lives. But in general, supplements don’t make people healthier.

And for another, high doses of some antioxidant supplements can be harmful. For example, they can oppose the effects of some medicines used to treat certain cancers. If you are being treated for cancer, make sure you tell your doctor about any antioxidants you are taking.

In contrast, when you eat many types of plant foods, you get a total package of antioxidants. There are hundreds of antioxidants in vegetables, fruit, nuts, seeds, extra virgin olive oil, wholegrains and tea — all foods recommended in Australia’s dietary guidelines.

What are the best antioxidants?

No single antioxidant does everything. You need a variety.

The best way to get them, and many other nutrients, is to eat a wide variety of plant foods. In particular, vegetables, fruit, nuts, seeds, extra virgin olive oil, wholegrains and tea.

There are two particular antioxidants — lutein and zeaxanthin — that might help prevent macular degeneration in the eyes of some older people. They are found in egg yolk, kale and green leafy vegetables. They are also in some antioxidant supplements.