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What is antioxidant?

Antioxidants are substances that reduce, neutralise and protect our body cells from damaged caused by free radicals and they can also be conceptualised as a line of defense against the risk of developing certain illness and disease.

Free radicals are highly reactive by-product of chemical process in the body which are harmful that damage cells and body tissues. They are also thought to be the cause of cancer, heart disease and other diseases. In the body free radicals can be formed through a process called oxidation and many outside forces influence the amount of free radicals such as exposure to the sun, smoke pollution, harmful bacteria and drugs.

Normally, the body can handle free radicals, but if the amount is excessive it may damage the cell and body tissue. Free radical damage is also accumulated with age.

Where are antioxidants found?

Our bodies produce their own antioxidants, but as we get older our ability to produce antioxidants weakens and therefore we need external source of antioxidants. They are found naturally in fruits, vegetables and also in other foods including nuts, grain, poultry, some meats and fish. Antioxidant substances include Beta-carotane, Lutein, Lycopene, Selenium, Vitamin C and Vitamin E. The sources of common antioxidants are:

  1. Beta-carotane

    Beta-carotane is a precursor to vitamin A (retinol). It is found in many foods that are orange in colour such as apricots, carrots, pumpkin, mangos, sweet potatoes and peaches. It is also present in some green and leafy vegetables including spinach and broccoli.

  2. Lutein

    Lutein is always best known related with healthy eyes, it is plentiful in green, leafy vegetables such as spinach, kale and collard green. Lutein combine with zeaxanthin and bilberry significantly enhanced antioxidant effect. Furthermore, when combined with vitamin C, these combination of antioxidants have been shown to significantly decrease the risk of cataracts.

  3. Lycopene

    Lycopene is an effective antioxidant found in papaya, guava, watermelon, tomatoes, apricots, pink grapefruit and blood oranges.

  4. Selenium

    Selenium is a component of antioxidant enzymes. It is not antioxidant nutrient but it is a mineral. In most countries, plant foods like rice and wheat are the major dietary sources. Selenium combines with glutathione can stop the growth of tumour and it protects the liver.

  5. Vitamin C

    Vitamin C also known as ascorbic acid is a water soluble vitamin. Vitamin C is a potent antioxidant found in citrus fruits and juices, spinach, broccoli, kiwi, strawberries, cranberry, cabbage and green peppers. It is also found in cereals, beef, poultry and fish. Researchers have found that cranberry juice can increase plasma antioxidant levels and raise levels of good cholesterol, therefore it can help to reduce the risk of heart disease.

  6. Vitamin E

    Vitamin E also known as alpha-tocopherol and present in many oils including wheat germ, corn and soybean oil. It is also found in apricots, broccoli, nuts, mango and other foods. Increasing dietary intake of vitamin E could help reduce the risk of developing Parkinson’s disease. Besides, combination of vitamin A, Vitamin E and carotenoids can improve the oxidant defence and immune system. Vitamin E (for subgroup tocotrienols only) show potent anticancer activity.

What are the benefits of antioxidants?

There is still a great deal of research to be done into potential health benefits of antioxidants. There is no proof of benefit and the evidence for using antioxidant vitamins to lower chronic disease is preliminary.


Antioxidants are widely used as ingredients in dietary supplements in the hope to maintaining health and preventing diseases such as cancer and coronary heart disease. Although initial studies suggested that antioxidant supplements might promote health, later large clinical trials did not detect any benefits. However diet which is rich in vegetables and fruits can improve health, promote general well being and therefore:

  • Eat a wide variety of cereal, fruit and vegetable in reasonable amounts than rely on supplement with few antioxidants.
  • Do regular exercise and eat 5 servings of fruits and vegetables per day through a balance diet, to provide the necessary components and may help ourbody develop natural antioxidant system. It has been suggested as the best way to make sure adequate intake of antioxidant nutrients.
  • Other substances present in natural sources of antioxidants play an important role in maintaining healthy living.
  • Before taking antioxidant supplement ensure the risk and benefit.
  • For some antioxidants, at higher concentrations it can have toxic effect and therefore, do not over supplement.
Last reviewed : 23 April 2014
Writer : Munira bt. Muhammad
Reviewer : Che Pun bt. Bujang