Free Radicals and Antioxidants: Nature's Little Helpers

A free radical is an atom in the body that is damaged and missing one or more electrons, making it unstable. Free radicals are produced in body cells as a normal part of metabolism, for example, as a by-product of fat oxidation. They are also created in the body by exposure to sunlight, x-rays, and pollutants such as tobacco smoke, car exhaust and ozone.

Free radicals attack body cells in a number of ways. They can damage mitochondria (the cells’ own energy powerhouses), rupture cell membranes, and damage, DNA thereby altering or destroying cell function.

The body can normally cope with low levels of free radicals but high levels may initiate or contribute to premature aging, atherosclerosis and heart disease, cancer, cataracts, arthritis, infertility in men, and other degenerative diseases.

Antioxidants are substances that combat or neutralize free radicals before excessive damage occurs to our body cells. Research into antioxidants is in early stages, and much of what is known is speculative. Nevertheless, antioxidants show promise as agents that can prevent or delay many disease processes.

Antioxidants may also help to stop damage occurring to the blood vessel walls by preventing the oxidization of cholesterol within the body. Oxidization of "bad" LDL cholesterol in the bloodstream is thought to play a key role in the development of fatty streaks and atherosclerosis in artery walls – and the accompanying increased risk of angina, heart attack and stroke.

You can make sure you are getting antioxidants by eating a wide variety of foods, particularly plant foods. Dietary antioxidants that you will get from food include vitamins, minerals and phytochemicals (including carotenoids). Vitamins E, C and beta-carotene are the most studied antioxidants for which important roles have been proposed.

Selenium, zinc, manganese and copper also have important roles as do various enzymes such as SOD, Co-Q10 and glutathione peroxidase.

Carotenoids are the red, yellow and orange pigments in fruits and vegetables. Beta-carotene is the most well known. Carotenoids have antioxidant properties and are thought to be potent cancer fighters.

For example, lycopene – which gives tomatoes their red color – is linked to a lower risk of prostate cancer in men. In one study, men who ate at least 10 servings of tomato-based foods each week showed 45% less risk of getting prostate cancer.

Lutein and zeaxanthin in spinach and broccoli are two carotenoids that have been linked to eye health in the elderly. Vitamin C, E and beta-carotene may also prevent or delay onset of cataracts.

Phytochemicals are a new class of non-vitamin compounds found in all fruits and vegetables. Early research is speculative but shows them to be potential cancer protectors. They seem to interact in all steps of the cancer process, by slowing, stopping or reversing each step.

Phytochemicals include:

For a balance of beneficial phytochemicals, eat at least three different colors of fruit and vegetables every day (as part of the recommended 5-9 servings per day). Include food from each of the following categories:

• Cruciferous vegetables such as broccoli, cabbage, cauliflower, brussels sprouts, kohlrabi
• Citrus fruits for vitamin C such as oranges and grapefruit
• Dark green and leafy vegetables such as spinach, kale, green pepper, mustard greens, lettuce, silverbeet
• Deep yellow/orange/red fruits and vegetables tomatoes, red pepper, carrots, rockmelon, pumpkin, sweet potato, mango, papaya

Phytoestrogens are plant hormones that are very weak versions of human estrogen. While different types of phytoestrogens are widespread in plant foods, it is the isoflavones (Genistein and Diadzn) in soybeans and soy foods that has the most potent estrogen-like effects on the body.

In countries where people eat diets high in soy, such as Japan, China and Korea, breast cancer rates are much lower than in the West, prostate cancer deaths are minimal, and unpleasant symptoms of menopause appear scant; there is no word for “hot flash" (or "hot flush") in Japanese.

Breast cancer: During childbearing years, phytoestrogens stave off breast cancer by blocking some of the naturally occurring estrogen and thereby acting as anti-estrogens. Even though estrogen is necessary for reproduction it can also encourage cancerous tumors to develop in breast tissue.

However, due to the way in which phystoestrogens in soy may react with certain treatment medications, people who have had breast cancer should always consult with a doctor before eating soy products or other phytoestrogen foods.

Menopause benefits: At menopause, when a woman's natural estrogen declines by 70%, phytoestrogens provide an estrogen “lift” to make up for the “lack” of the hormone without raising the risk of cancer. This may reduce the symptoms of menopause such as hot flushes, headaches and mood swings.

Consuming soy-rich phytoestrogens may also reduce the risk of osteoporosis by lessening the bone loss that accompanies estrogen fall-off at menopause, and reduce the risk of heart attack by raising the “good” HDL cholesterol which keeps arteries clear. It may also reduced the thinning of vaginal tissues.

Prostate cancer: In men, phytoestrogens appear to act as a blocker of testosterone can spur the growth of prostate tumors.