All about Antioxidants

You will no doubt have heard the term antioxidant, but do you really know what it means?

Antioxidant is a term applied to any compound which can stabilise free radicals. Antioxidants are not a particular nutrient in foods, they can be vitamins, minerals or plant phytochemicals, but they all have this ability to 'mop up' free radicals and to prevent them from causing inflammation and damage to cells in the body.

What's a free radical?

Free radicals are unstable molecules. They occur all the time as a result of body processes, from external sources such as pollution in the air or from smoke or from UV light. Exercise can induce free radicals too, but they have a beneficial effect in that instance as they sensitise muscle cells to insulin.

Because free radicals don't have a full complement of electrons, they steal electrons from other molecules and damage those molecules in the process. Antioxidants neutralize free radicals by giving up some of their own electrons. In doing this, they act as a natural "off" switch for the free radicals. This helps break a chain reaction that can affect other molecules in the cell and other cells in the body.

Where do we find antioxidants?

Our bodies are good at producing some antioxidants themselves, such as glutathione, coezyme Q10 and alpha-lipoic acid. However, these should be supplemented with a good daily intake of antioxidants from food, primarily plant foods.

There are thousands of antioxidants found in food. They may be in the form of vitamins, such as Vitamins E, A and C or minerals - selenium, zinc and copper. They could be phytochemicals (plant chemicals) which are divided into groups such as the carotonoids, flavonoids or anthocyanins. Such is the range that it would be ludicrous to try to devise a diet that provides the perfect mix of them all. An excellent strategy is to simply include many fruits and vegetables as well as wholegrain cereals, seeds, nuts and legumes in your diet- ie a good variety of plant foods.

A balanced diet including a good variety of plant foods will supply all the antioxidants you need

Don't forget tea and coffee contain antioxidant phytochemicals too! A good rule of thumb is colour and strong flavour to indicate some of the most powerful antioxidant rich foods. Include reds, yellows, purples, green and flavours such as coffee, tea, garlic, ginger, turmeric and other spices and you will have included a plethora of antioxidants.

Should I take an antioxidant supplement?

Given their important role, why not take an antioxidant supplement for even greater efficacy in reducing free radicals? Studies have not shown the effect of supplements to be as good as antioxidants in real food. And, in some cases they can be harmful.

If you are being treated for cancer then it is not advisable to take antioxidant supplements. Radiotherapy and certain types of chemotherapy are designed to increase the production of reactive oxygen species -a type of free radical.

These reactive oxygen species can react with genes inside cells and are potentially fatal to cells. If that damage is to cancer cells, then that is the desired effect. But, reactive oxygen species are not necessarily selective, and so many normal healthy cells can also be killed.

The dilemma is that high dose antioxidant supplements could protect healthy cells from reactive oxygen species damage, reducing the collateral damage of cancer treatment. However, there is also the possibility that high doses of antioxidants could stabilise (deactivate) many of the reactive oxygen species which were supposed to kill cancer cells, reducing the effectiveness of the chemotherapy or radiotherapy.

Women with breast cancer who take antioxidant supplements during their chemotherapy or radiotherapy treatment have been found to have higher rates of mortality and also of cancer recurrence.

None of this applies to the levels of antioxidants found naturally occurring in plant foods. Thy have a protective effect against the risk of cancer, and during treatment.

So what's the take home message?

• To decrease risk of chronic diseases associated with inflammation- such as cardiovascular disease, type 2 diabetes, dementia and cancer- supplement your body's naturally produced antioxidants with antioxidants found in food.

• Eat lots of plant foods, including a variety of colours and flavours to get the whole spectrum of antioxidant types.

• Don't use an antioxidant supplement unless advised to by your doctor or nutrition expert.

• Look for strong colours and flavours in plant foods.