Many
scientists believe that antioxidants are extremely valuable additions to anyone's diet.
Stress, exposure to
ultraviolet,
smoke, too much
exercise and normal
metabolism (especially of
fatty foods) all produce
free radicals, which cause
cell damage of various sorts. This doesn't just contribute to
aging (of which it may be one of the main fundamental causes) but can cause
cancer and probably contributes to
heart disease,
arteriosclerosis and
diabetes.
Vitamins notable for their antioxidant properties are vitamin A, vitamin C and vitamin E, but tests carried out in 2000 suggest that taking very high doses of these vitamins is likely to do more harm than good. The mineral selenium is used in making antioxidant enzymes, but is highly toxic if you take too much. Fruit and vegetables generally contain a range of antioxidants; cooked tomatoes, especially with the skin, are a particularly good source (yay ketchup!). Red wine is also rich in antioxidants; for some reason Chilean red wine seems to be notable for this. But perhaps the single most potent source of antioxidants in many of our diets is tea, which is rich in polyphenols and catechin. Green tea is extremely rich in antioxidants - and is clearly the tea best-known for its health benefits - but Oolong is not far behind, possessing more polyphenols but less catechin; black tea (the tea most often drunk in the West) also contains these, but drinking it with milk appears to negate its benefits; tests have shown that while straight black tea increases the levels of antioxidants in our blood, milky tea leaves them unchanged. The reasons for this are unclear, but presumably something in the milk binds with the antioxidants - probably the fat. Coffee also turns out to contain significant levels of antioxidants, possibly even enough to outweigh any damage caused by the caffeine.
Antioxidants are also used as preservatives - vitamin C is an especially popular one, often under the name ascorbic acid or its E-number, E300. Outside of food, antioxidants such as vitamin E, vitamin C and beta-carotene are used in skin care preparations where it is hoped they will slow the breakdown of collagen; and antioxidants are added to petrol (gas if you're American), paints, plastics and so on to prevent spoiling through oxidation.