The human body and its cells face formidable threats from poverty to mutant viruses. Another threat comes from nasty chemicals called free radicals. They are capable of damaging cells and genetic material.
Free radicals are unstable molecules and they “steal” electrons from other molecules causing damage to DNA and other cells. Antioxidants are compounds in foods that neutralize these free radicals. These powerful substances, which mostly come from the fresh fruits and vegetables we eat, prohibit and prevent oxidation of other molecules in the body. Antioxidants are very important to good health, because if free radicals are left unchallenged, they can cause a wide range of illnesses and chronic diseases.
The human body naturally produces free radicals and the antioxidants to counteract their damaging effects. However, in most cases, free radicals far outnumber the naturally occurring antioxidants. In order to maintain the balance, a continual supply of external sources of antioxidants is necessary in order to obtain the maximum benefits of antioxidants. Antioxidants include the nutrient antioxidants, vitamins A, C and E, and the minerals copper, zinc and selenium.
Impact of free radicals
Deterioration of the eye lens, which contributes to blindness, inflammation of the joints (arthritis), damage to nerve cells in the brain which contributes to conditions such as Parkinson’s or Alzheimer’s disease. Acceleration of the ageing process. Increased risk of coronary heart disease, since free radicals encourage low-density lipoprotein (LDL) cholesterol to stick to artery walls. Certain cancers, triggered by damaged cell DNA.
Sources of antioxidants
A diet high in antioxidants may reduce the risk of many diseases, including heart disease and certain cancers. The protective effect of antioxidants continues to be studied around the world. For instance, men who eat plenty of the antioxidant lycopene (found in tomatoes) may be less likely than other men to develop prostate cancer. Lutein, found in spinach and corn, has been linked to a lower incidence of eye lens degeneration and associated blindness in the elderly. Flavonoids, such as the tea catechins found in green tea, are believed to contribute to the low rates of heart disease in Japan.
Good sources of specific antioxidants are:
- 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 – green, leafy vegetables like spinach, and corn
- Lycopene – tomatoes, pink grapefruit and watermelon
- Manganese – seafood, lean meat, milk and nuts
- Polyphenols – thyme and oregano
- Selenium – seafood, offal, lean meat and whole grains
- Vitamin A – liver, sweet potatoes, carrots, milk, and egg yolks
- Vitamin C – oranges, blackcurrants, kiwifruit, mangoes, broccoli, spinach, capsicum and strawberries
- Vitamin E – vegetable oils (such as wheat germ oil), avocados, nuts, seeds and whole grains
- Zinc – seafood, lean meat, milk and nuts
- Zoochemicals – red meat, offal and fish
There is increasing evidence that antioxidants are more effective when obtained from whole foods, rather than isolated from a food and presented in tablet form – and some supplements can actually increase cancer risk. A well-balanced diet, which includes consuming antioxidants from whole foods, is best. If you insist on taking a supplement, seek supplements that contain all nutrients at the recommended levels.
Increasing the antioxidant intake is essential for optimum health, especially in today’s polluted world. Because the body just can’t keep up with antioxidant production, a good amount of these vitamins, minerals, phytochemicals, and enzymes must come from one’s daily diet. It is also thought that antioxidants and other protective constituents from vegetables, legumes and fruit need to be consumed regularly from early life to be effective. See your doctor or dietitian for advice.