Antioxidants are vitamin, minerals and enzymes that work on the cellular level and that function as cell protectors in our bodies. Antioxidants protect our bodies in the following manner: During normal cellular metabolism, oxygen, an essential element for life, can create damaging byproducts. These oxidized cellular byproducts, called free radicals, bazinga are highly unstable and steal components from other cellular molecules, such as fat, protein, or DNA, thereby spreading the damage. This damage continues in a chain reaction, and entire cells soon become damaged and die. This process, known as peroxidation, is helpful because it helps the body destroy cells that have outlived their usefulness and neutralizes viruses, bacteria, and parasites. However, when left unchecked, peroxidation also destroys or damages healthy cells.
Free radicals are also created by exposure to various environmental factors, such as pollution, tobacco smoke, radiation, and pesticides. Normally, the body can handle free radicals, but if antioxidants are unavailable, or if the free-radical production becomes excessive, damage can occur. Too many free radicals in our bodies may cause heart damage, cancer, cataracts, and a weak immune system leading to an increased risk of infections. Additionally, free radical damage accumulates with age.
Antioxidants bind to the free radicals and either transforms them into non-damaging compounds or repair cellular damage. More important, antioxidants return to the surface of the cell to stabilize rather than damage other cellular components. Common vitamin antioxidants include vitamin C, and vitamin E in conjunction with the mineral selenium.
Phytochemicals are substances in plants that are being investigated for their antioxidant and anticancer activity and health-promoting potential. The phytochemicals called carotenoids (such as lutein, beta-carotene, and lycopene) have been shown to have powerful antioxidant properties. Another common phytochemical compound that may be familiar to you is soy isoflavones (discussed in Part 2). Researchers are discovering more health benefits from these plant substances every year.
Here are some good food sources of common antioxidants and phytochemicals:
Vitamin C: Also called ascorbic acid, vitamin C is a water-soluble (not stored in the body) vitamin found in all body fluids. It protects tissues from breakdown by free radical formation. Important sources include green leafy vegetables, broccoli, green peppers, tomatoes, raw cabbage, citrus fruits, strawberries, and potatoes.
Vitamin E: A fat-soluble vitamin that can be stored with fat in the liver and other tissues. It decreases free radical damage in connective and organ tissue, accelerating wound healing and protecting tissue from damage. Vitamin E increases immunity and protects against cataracts and macular degeneration. Vitamin E protects cells from the cancerous effects of X-rays, chemicals, air pollutants, and ultraviolet light. Important sources include vegetable oil, nuts, seeds, whole grains, wheat germ, olives, avocados, green leafy vegetables, and fish-liver oil.
Carotenoids: These potent phytochemicals are the fat-soluble pigments abundant in yellow, orange, red, and green fruits and vegetables. Beta-carotene, alpha-carotene, and beta-cryptoxanthin are carotenes that are converted into vitamin A (a vitamin essential for normal metabolism and health) or retinol (the active form of vitamin A) in the body.
The provitamin-A carotenoid receiving the most research attention is beta-carotene. Special controls in our body limit how much beta-carotene becomes vitamin A, leaving the remainder to act as an antioxidant. It can disarm reactive oxygen molecules generated by sunlight and air pollution and prevent free radical damage to skin, eyes, and lungs. Carrots, squash, broccoli, sweet potatoes, tomatoes, kale, collards, cantaloupe, peaches, and apricots are particularly rich sources of beta-carotene.
The carotenoid lycopene is responsible for the red color in fruits and vegetables, including tomatoes, red grapes, watermelon, and pink grapefruit. It is also found in papayas and apricots. It does not convert to vitamin A but may have important cancer-fighting properties and other health benefits. The beneficial actions of most carotenes such as those in tomatoes, corn, and carrots appear to be enhanced by cooking them, especially in oil (preferably olive, canola, or another monounsaturated oil). Cooking increases their nutritional value by breaking down the tough cell walls and releasing the nutrients. For example, the body cannot obtain lycopene from raw tomatoes. The body best absorbs lycopene from cooked tomatoes (such as tomato juice and tomato sauce) along with a bit of dietary fat.
Selenium: This mineral is thought to help fight cell damage by oxygen-derived compounds and thus may help protect against cancer. It works together with vitamin E. It is best to get selenium through foods, because large doses of the supplement form can be toxic. Good food sources include fish, shellfish, red meat, whole grains, Brazil nuts, eggs, chicken, and garlic.
In Part 2, good food sources and the health benefits of a few more common antioxidants and phytochemicals are presented.
Copyright 2006 Mary El-Baz. All rights reserved.
Mary El-Baz, PhD is the author of Building a Healthy Lifestyle: A Simple Nutrition and Fitness Approach and Easy and Healthful Mediterranean Cooking, an invaluable nutritional program for anyone to build a healthy lifestyle and a collection of savory, nutritious Mediterranean recipes. Dr. El-Baz holds a doctorate in Holistic Nutrition from Clayton College of Natural Health and degrees from the University of Missouri.
Look for her books on http://search.barnesandnoble.com/booksearch/results.asp?WRD=Mary+El%2DBaz&z=y&cds2Pid=9481 and other fine online booksellers. A forthcoming book that builds on the Building a Healthy Lifestyle foundation, Transform Your Core 6-Week Workbook, a six-week weight loss plan to rev up your fat-burning metabolism and build lean muscle to transform your midsection from fat and flabby to slim and trim, will be available just in time for your New Years resolution!