Words: Gagan Cheema
Antioxidants play an important role in protecting the body from many diseases – and the good news is they’re a natural part of a balanced diet.
What are antioxidants?
The mention of ‘antioxidants’ conjures an image of tiny crusaders, waging a battle for good health and optimum wellbeing throughout our body. But what exactly are antioxidants and why are they so good for us?
Antioxidants are naturally occurring molecules in certain foods that help to neutralise oxidation in the body’s cells. It’s this oxidation process that can produce undesirable ‘free radicals’ – molecules that are involved in the ageing process and can contribute to a range of serious illnesses.
Our bodies are designed to neutralise free radicals naturally, but when external factors – such as smoking, alcohol or pollution – are added to the mix, our bodies sometimes need some help to combat them. And that’s when antioxidants come into play.
Some of the most common antioxidants come in the form of Vitamins A, C and E, the minerals copper, zinc and selenium, and carotenoids such as betacarotene, which are present in a number of fresh foods.
Benefits of antioxidants
A diet high in antioxidants can help reduce the risk of degenerative conditions that have been linked to the oxidation of the body’s cells and the damaging chain-reaction effect of free radicals. These conditions include certain cancers, coronary heart disease, strokes and damage to brain nerve cells that, in turn, can contribute to illnesses like Parkinson’s or Alzheimer’s disease.
The antioxidants actually expel free radicals from the body cells, thereby preventing or reducing the damage caused by oxidation1.
Sources of antioxidants
Most of the antioxidants we consume come from plants – they are abundant in many fruits and vegetables – but they can also be found in other foods, such as nuts, whole grains and some meats, poultry and fish.
Fruit and vegetables are the principal sources of two of the major dietary antioxidants: Vitamin C and carotenoids. Although many people do not realise it, certain fruit and vegetables also contain the third major antioxidant nutrient, Vitamin E, although its major sources are cereal oils, olive oil and nuts2,3.
While it’s possible to purchase a range of antioxidant vitamin supplements, studies offer little support that taking Vitamin C, Vitamin E, betacarotene or other single antioxidants provides substantial protection against heart disease, cancer or other chronic conditions.
The evidence also seems to suggest that antioxidants are more effective when consumed in a well-balanced, varied diet rather than in tablet form4,5.
Good sources of antioxidants
Betacarotene: pumpkin, mangoes, apricots, carrots, spinach, parsley, watermelon
Flavanoids: tea, green tea, citrus fruits, onions, apples
Isoflavanoids: soybeans, tofu, lentils, peas, milk
Lycopene: tomatoes, watermelon
Capsanthin: red and yellow peppers, oranges
Manganese: seafood, lean meat, milk, nuts
Selenium: seafood, offal, lean meat, whole grains
Vitamin C: oranges, blackcurrants, kiwi fruit, mangoes, broccoli, spinach, capsicum, strawberries
Vitamin E: avocados, nuts, seeds, whole grains
Zinc: seafood, lean meat, milk, nuts
Polyphenols: thyme, oregano
Copper: seafood, lean meat, milk, nuts
Lignans: sesame seeds, bran, whole grains, vegetables
Lutein: leafy greens, corn
References: 1 Commonwealth Scientific and Industrial Research Organisation (CSIRO), 2011. 2 Dragsted LO, Pedersen A, Hermetter A, et al. ‘The 6-a-day study: effects of fruit and vegetables on markers of oxidative stress and antioxidative defense in healthy nonsmokers ‘, American Journal of Clinical Nutrition, 2004; 79: 1060–1072. 3 Catherine Rice-Evans, Nicholas J. Miller ‘Antioxidants – the case for fruit and vegetables in the diet ‘, British Food Journal, 1995; 97( 9): 35 – 40. 4 Cook NR, Albert CM, Gaziano JM, et al. ‘A randomized factorial trial of vitamins C and E and beta carotene in the secondary prevention of cardiovascular events in women: results from the Women’s Antioxidant Cardiovascular Study’, Archives of Internal Medicine. 2007; 167(15):1610–1618. 5 Bjelakovic G, Nikolova D, Gluud LL, et al. ‘Antioxidant supplements for prevention of mortality in healthy participants and patients with various diseases’ Cochrane Database of Systematic Reviews. 2008; (2):CD007176.
Information provided in this article is not medical advice and you should consult with your healthcare practitioner. Australian Unity accepts no responsibility for the accuracy of any of the opinions, advice, representations or information contained in this publication. Readers should rely on their own advice and enquiries in making decisions affecting their own health, wellbeing or interest.