Antioxidant deficiency in our diet is linked to many common diseases. At a cellular level we already know that oxygen is vital for all living beings to maintain normal cellular activity and body processes. However, oxygen is also highly reactive during biochemical reactions and therefore has a potential to become unstable and capable of causing damage of genetic material. In this form they are known as ‘Free radicals’ and they are able to ‘oxidize’ other neighbouring molecules causing cell damage that may lead to inflammation, arterial damage, cancer and aging.
What are Free Radicals?
Free radicals are produced as part of a normal physiological process that occurs during the breakdown of food (e.g. frying or barbequing), or environmental exposures such as sun damage, cigarette smoke, pollution, radiation. Substances with an ability to disarm free radicals are called ‘antioxidants’.
Role of Antioxidants
Antioxidants primarily protect our bodies from cell damage caused by free radicals. They helps to stabilize free radicals therefore stopping them from causing any damage. There is substantial evidence from laboratory and animal studies that antioxidants are able to prevent or slow down the development of disease.
To date hundreds (possibly thousands) of antioxidant nutrients has been discovered. Many are found in fruits and vegetables, some examples are, beta-carotene, lycopene, lutein, vitamin A, C, E, selenium and flavinoids.
- Beta-carotene in a variety of dark orange, red, yellow and green vegetables and fruits e.g. spinach, sweet potato, carrots, red and yellow peppers, apricots, cantaloupe and mango.
- Vitamin C is found in citrus fruits/juices, berries, dark green vegetables (e.g. green peppers, spinach, broccoli, watercress and asparagus).
- Vitamin E in a variety of nuts, seeds, whole grains, wheat, sheat germ, brown rice, oatmeal, soya beans, legumes, dark green leafy vegetables and vegetable oils, e.g. olive, soybean and corn, nuts.
- Selenium is found in brown rice, chicken, eggs, brazil nuts, brewer’s yeast, oatmeal, dairy products, garlic, molasses, onions, salmon, seafood, tuna, whole grains and most vegetables.
Antioxidants & Our Health
Our bodies continuously use antioxidants to minimize the molecular damage by extracting it from food sources. Therefore a balance of antioxidant nutrient intake and exposure to free radicals determines our health status. There is good indication that reduction of ‘oxidative stress’ influences how we age and risk of certain diseases. Nutritionally, we are already aware that low levels of vitamin C are related to a stronger immune system, whilst in the elderly it lowers the risk of developing cataracts. Supplementation of vitamin E and C halves the risk of heart attacks and strokes. However one must remember that although antioxidants may be extremely beneficial for good health they are not the answer to everything and there is still much research to be done.
Free radicals contribute to the development of cancer, chronic and other diseases. A nutritional approach to good health incorporates the use of antioxidants by consuming foods rich in antioxidant content, whilst minimizing exposure to factors that increase its production. Never use antioxidants to replace a good healthy diet and always inform your health care provider about any supplements that you may be using. The use of antioxidants as a supplement should be done with care as they may interact with some medicines and research shows the high-dose supplementation may be harmful in some cases. Never use antioxidants in place of medical treatments or consulting your doctor.
- Albanes D, Heinonen OP, Taylor PR, et al. (1996). Alpha-tocopherol and beta-carotene supplements and lung cancer incidence in the alpha-tocopherol, beta-carotene cancer prevention study: effects of base-line characteristics and study compliance. J Natl Cancer Inst. 88:1560-70.
- Holford P (2004). The new optimum nutrition bible. New York. The Crossing Press.
- Lee IM, Cook NR, Gaziano JM, et al (2005). Vitamin E in the primary prevention of cardiovascular disease and cancer: the Women’s Health Study: a randomized controlled trial. JAMA. 294:56–65.
- NCCAM. (2011). Antioxidant supplements for health: An introduction. NCCAM. [Accessed: 6 Sept 2012] [Weblink]
Revised: June 2013