What do luscious, red strawberries, midnight hued blueberries, shiny black and red beans and deep green spinach have in common? Not only do they tantalize our taste buds, but they're all rich sources of antioxidants - nutrients that are believed to protect the body from oxidation, a process associated with heart disease, cancer and aging itself.
Oxidation occurs as part of the normal metabolic process that creates unstable free radicals, which can damage the body's DNA. Free radicals also are caused by environmental factors such as smoking, radiation and pollution. The body is constantly working to repair damage to its DNA, but throughout time and with too many assaults it can become overwhelmed and leave itself open to disease.
Antioxidants from the foods we eat help the body in its fight against free radicals. Most of the antioxidants we take in are scavenging antioxidants - they donate electrons to free radicals, effectively neutralizing them and preventing them from damaging DNA.
A small percentage of cancers, between 5 and 10 percent, are caused by damaged DNA that is inherited. But most cancers are caused by external factors such as smoking, radiation and pollution of air, water, food or the workplace environment. Although we may not be able to avoid all these negative external influences, we can try to protect our bodies by eating foods that work to undo some of the damage.
Antioxidants are found in a wide range of foods but are especially abundant in fruits, vegetables, beans, whole grains, herbs, teas and wine. There are numerous known antioxidants, each working in its own unique way and often in concert with other antioxidants.
A number of vitamins work as antioxidants, especially vitamins C and E. Vitamin C, highly effective as a scavenger, is found in a range of fruits and vegetables and is especially high in citrus fruits, strawberries, blackberries, blueberries, spinach and tomatoes.
Vitamin E is found in fruits, vegetables, nuts, whole grains, corn, soybean and peanut oil.
Many studies show that people who eat a diet rich in fruits and vegetables have a lower risk of heart disease, but a recent controlled trial of three antioxidants - vitamin C, beta carotene and vitamin E - taken as supplements failed to show a benefit. It may be that people who eat plenty of fruits and vegetables have a generally healthier lifestyle or perhaps when taken as supplements, other chemical nutrients found in the whole foods are missing.
Carotenoids are the orange-red pigments found in carrots, sweet potatoes, mangos and many other fruits and vegetables. One of about 600 carotenoids, beta-carotene is a precursor of retinol, or vitamin A.
Flavenoids make up a larger group of more than 2,000 antioxidants found in fruit, vegetables, coffee, tea, beer and wine. Numerous studies have shown they have a protective effect against heart disease and a number of cancers. Quercetin, a flavenoid found in berries, apples, tea, broccoli and onions may protect against gastrointestinal cancer.
Selenium, a trace element found mainly in nuts, cereals and fish, has been associated with a reduced risk of some types of cancer.
Sulforaphane, found in broccoli and broccoli sprouts has been shown to protect against stomach cancer as well as age-related macular degeneration, a leading cause of blindness in older adults. Three-day old broccoli plants are an especially rich source of sulforaphane.
Lutein, found in spinach, kale and other green, leafy vegetables, may improve the symptoms of macular degeneration.
Zinc is widely used as a protection against colds and flu. When used in combination with selenium, it appears to boost immune function and help the body fight infection.
Keep it simple
There's no need to feel overwhelmed by the literally thousands of antioxidants and their potential benefits. The USDA recently completed a study of the most potent sources of antioxidants, and many every day foods were featured on the list: blueberries; red, pinto and black beans; cranberries, artichokes, prunes, plums, blackberries, raspberries and strawberries; red delicious, Granny Smith and Gala apples; pecans, plums and russet potatoes.
Among the most potent antioxidants, blueberries have been associated with improved short-term memory, balance and coordination in Alzheimer's patients. They mitigate the effects of radiation treatment in cancer patients, and in one animal study, they were affective in lowering cholesterol.
Brightly colored foods, especially those that are red, black, purple and dark green, tend to be high in antioxidants. So to be sure you're getting a healthy dose, a good rule of thumb is to choose a variety of colorful fruits and vegetables. The more colors, the better.
And you can boost your antioxidant levels with well-chosen beverages. As well as fruit juices, try a cup of green or black tea with your meals. Tea has the advantage of being calorie free and has significantly less caffeine than coffee.
One study found that even when it's decaffeinated, tea is still a good source of antioxidants. Adding lemon to tea doesn't seem to detract from its benefits, but a number of studies show that adding milk to tea - the way it's commonly served in England and Ireland - may reduce antioxidant levels.
Coffee and hot cocoa also are rich in antioxidants.
Red wine is a potent source of antioxidants, which may explain the protection the French enjoy from heart disease despite a diet relatively rich in fat.
For those who would rather avoid alcohol, Italian researchers have found a way to capture the beneficial effects of red wine in a pill.
Eating a diet rich in antioxidants is a simple and delicious prescription. Focus on a wide variety of colorful fruits and vegetables, beans, whole grains and nuts.
If you make these the centerpiece of your diet - supplemented with moderate servings of fish, meat and low-fat dairy products - you'll eat well and be giving your body the tools it needs to make ongoing repairs at the cellular levels and fight off environmental assaults.