THE ARTICLE
Our bodies are constantly producing free radicals as a result of the millions of processes that take place every day in order to keep us functioning smoothly. These processes all require oxygen, something essential for life, though the same oxygen also can produce harmful oxidant substances that can cause damage to our cells and lead to chronic disease. In addition, free radicals can be obtained through external sources such as pollution, exposure to the sun, smoking, stress, alcohol and unhealthy foods. Antioxidants, as the name suggests, help to get rid of this oxidative damage.
When oxygen is metabolised, it creates “free radicals” that steal electrons from other molecules, causing damage. Free radicals are chemically active atoms or molecular fragments that have a charge due to an excess or deficient number of electrons. Because one or more of their electrons is unpaired, free radicals are highly unstable. They will scavenge your body to grab or donate electrons, thereby damaging cells, proteins, lipids and the genetic material of our DNA. Oxidative stress occurs when the production of free radicals is beyond the protective capability of the body’s antioxidant defences.
The same process that creates rust on an iron object or makes a sliced apple begin to turn brown causes oxidation inside our body, creating a breakdown of cells. Free radicals produced by this breakdown attack healthy cells in their search for electrons, which weakens immunological functions as well as speeding up the aging process, and are also linked to several diseases such as cataracts, various forms of cancer, and heart disease. Some studies also indicate possible links to arthritis and several other chronic conditions.
Some of the degenerative conditions caused by free radicals include:
• Deterioration of the lens of the eye, causing cataracts, glaucoma and macular degeneration
• Joint inflammation and arthritis
• Diabetes I and II, as oxidants inhibit glucose metabolism
• Damage to nerve cells in the brain, which contributes to conditions such as Parkinson’s or Alzheimer’s disease, senile dementia and Huntington’s disease.
• Inflammatory bowel diseases such as ulcerative colitis and Crohn’s disease
• Increased wrinkles, as the skin’s supportive collagen is easily subject to free radical damage
• Cardiovascular disease, caused by free radicals encouraging low density lipoprotein (LDL) cholesterol to adhere to artery walls.
• Certain cancers, triggered by damaged cell DNA.
• Accelerated aging of tissues and organs
Antioxidants work by giving up electrons and neutralising free radicals so that they do not induce any more oxidative damage. Unlike other molecules, antioxidants do not become reactive when they lose an electron.
Numerous studies point to the protective effect of antioxidants. For instance, men who eat plenty of tomatoes (which are high in lycopene) may be less likely than other men to develop prostate cancer, and flavonoids, such as the tea catechins found in green tea, are believed to contribute to the low rates of heart disease in Japan.
Certain antioxidant enzymes are produced within the body itself. The most common of these naturally occurring antioxidants are superoxide dismutase, catalase, and glutathione. Superoxide dismutase changes the structure of oxidants, breaking them down into hydrogen peroxide. Catalase in turn, breaks down hydrogen peroxide into water and tiny oxygen particles or gasses. Glutathione is a detoxifying agent, which binds with different toxins to change their form, enabling them to be excreted as waste.
The best way to avoid free radical damage is to consume a diet high in antioxidants. You probably already receive some antioxidants every day in the foods you eat that contain antioxidant vitamins and minerals such as copper and zinc, carotenoids and polyphenols. The most well known antioxidants include the vitamins A (found in liver, dairy, and fish), C (found in red bell peppers and citrus fruits), E (found in oils, fortified cereals, seeds, and nuts), and the mineral selenium (found in Brazil nuts, meats, tuna, and plant foods).
Non-nutrient antioxidants such as phytochemicals are believed to have even greater antioxidant effects than either vitamins or minerals. The carotenoids beta-carotene, lutein, and lycopene also have high antioxidant activity and are responsible for adding brilliant color to many fruits and vegetables, such as carrots, pumpkins and sweet potatoes. Lutein, linked to a lower incidence of eye lens degeneration and associated blindness in the elderly, is abundant in leafy green vegetables such as spinach and kale. Lycopene is present in red fruits and vegetables, most notably in tomatoes, and anthocyanins can be found in cranberries.
Some good sources of antioxidants include:
- Allium sulphur compounds - leeks, onions and garlic.
- Anthocyanins - eggplant, grapes and berries.
- Beta-carotene - pumpkin, mangoes, apricots, carrots, spinach and parsley.
- Catechins - red wine and tea.
- Copper - seafood, lean meat, milk and nuts.
- Cryptoxanthins - red capsicum, pumpkin and mangoes.
- Flavonoids - tea, green tea, citrus fruits, red wine, onion and apples.
- Indoles - cruciferous vegetables such as broccoli, cabbage and cauliflower.
- Isoflavonoids - soybeans, tofu, lentils, peas and milk.
- Lignans - sesame seeds, bran, whole grains and vegetables.
- Lutein - leafy greens like spinach, and corn.
- Lycopene - tomatoes, pink grapefruit and watermelon.
- Manganese - seafood, lean meat, milk and nuts.
- Polyphenols - thyme and oregano.
- Selenium - seafood, organ meats, lean meat and whole grains.
- Vitamin C - oranges, red bell peppers, kiwi fruit, mangoes, broccoli, spinach, capsicum and strawberries.
- Vitamin E - vegetable oils, avocados, nuts, seeds and whole grains.
- Zinc - seafood, lean meat, milk and nuts.
- Zoochemicals - red meat, organ meats and fish.
Some studies suggest that antioxidants are less effective when not ingested from a food source, but are taken in supplement form. For example, vitamin A (beta-carotene) has been associated with a reduced risk of certain cancers but an increase in others, such as lung cancer in smokers, if vitamin A is taken as a supplement.
Another study examining the effects of vitamin E found that taking a supplement of the vitamin did not confer the same benefits as getting it from food. Also, antioxidant minerals or vitamins can actually become damaging ‘oxidants’ if they are taken at levels significantly above the recommended amounts for dietary intake.
A well-balanced diet, which includes consuming antioxidants from whole foods such as fresh fruits, vegetables, whole grains, lean meats and dairy products every day, is the best way to ensure you are getting the most benefits. If you must take a supplement, look for those that contain all nutrients at the recommended levels.
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