Antioxidants are substances, not always vitamins, that protect our cells against the effects of free radicals. Does that sound complicated? Let’s break it down to some simple concepts.
Free radicals are molecules that are normally produced in the body when you metabolize food or when you are exposed to environmental toxins, such as tobacco or radiation. Scientists recognize that free radicals play an integral role in the damage of the human cells resulting in diseases,such as cancer and coronary artery disease or in conditions, such as premature aging. (1,2,3)
Free radicals are actually unstable molecules that have an odd, unpaired electron. The bonds of these electrons are weak, creating a free radical which quickly reacts with other compounds as it tries to capture another electron to regain stability. In essence, the free radical attacks the nearest stable molecule in an attempt to steal an electron. If successful, the molecule which lost an electron now becomes a free radical and begins a chain reaction, in search of an electron to regain stability. Once this entire process has started it can result in the death or disruption of cells.
Normally, using antioxidants, the body can handle free radicals. However, if the production of free radicals becomes excessive or there are no antioxidants, damage can occur. Free radical damage accumulates with age and becomes more and more evident as the individual becomes older.
Antioxidants are molecules that safely interact with these free radicals and terminate the chain reaction. This all happens before any vital molecules are damaged. There are several enzyme systems within the body that helped to neutralize free radicals, as well as antioxidant vitamins and minerals which include vitamin E, beta-carotene, vitamin C, Vitamin A, lycopene and selenium. (4)
Research has focused on the role that antioxidant vitamins play in the reduction of cardiovascular disease. At this time, according to the American Heart Association, the data appears incomplete. The American Heart Association does not recommend using antioxidant vitamin supplements for the expressed purpose of fighting free radical damage in the body. However, they do recommend that people eat a variety of nutrient rich foods. (5)
In the case of cancer, there is considerable laboratory evidence from chemical and cell cultures that indicate antioxidants will slow or may even prevent the development of cancer. Unfortunately, information from recent clinical trials in humans is less conclusive. (6)
There were five large-scale clinical trials published in the 1990s, all of which reached different conclusions about the effects of the antioxidant vitamins and minerals on cancer. Each of these studies evaluated different antioxidants using different subjects in the study. At this time there are three large scale clinical trials which continue to investigate the effect of antioxidants on cancer. The majority of these clinical trials appear to focus on vitamin C and beta-carotene.
However, researchers and scientists, as well as physicians, recognize and recommend that individuals who are interested in receiving adequate amounts of vitamins and minerals in their diet should do so by eating a well-balanced diet that consists of whole foods. This means eating raw fruits and vegetables that have not been cooked or otherwise processed. Many of the vitamins and minerals in food are eliminated or destroyed during processing or heating so it is important to eat as much raw whole food as possible.
Researchers also know that the human body is not able to absorb vitamins obtained from supplementation as well as it does to those vitamins and minerals it can metabolize from food. This concept is called bioavailability. It means that the vitamins which are found in raw fruits and vegetables are more easily incorporated into the human cell than those vitamins and minerals which are manufactured in a laboratory – even though they may both look very similar under the microscope.
Antioxidant substances include beta-carotene, lutein, lycopene, selenium and vitamin A, vitamin C and vitamin E. These vitamins and minerals are found in many foods, fruits, vegetables, grains, nuts, and some meats and poultry. Beta-carotene is found in foods that are orange in color, such a sweet potatoes, carrots, cantaloupe and apricots. Some green leafy vegetables, including spinach and kale, are also rich in beta-carotene.
Lutein is abundantly available in green leafy vegetables and lycopene is found in tomatoes, watermelon, apricots, pink grapefruit and blood oranges. Selenium is a mineral that is found in plant foods such as rice and wheat. The amount of selenium found in the soil will vary by region and this will determine the amount of selenium found in the food. Just
Vitamin A. is found in liver, sweet potatoes, carrots, milk and mozzarella cheese. Vitamin C, also called ascorbic acid, is found in many fruits, especially citrus fruits such as oranges, limes, lemons and grapefruits. Vitamin E is an oil-based vitamin and found is in safflower, corn, soybean, almonds, broccoli and mangoes.
While recent clinical trials are not conclusive about the evidence of antioxidants in the prevention of heart disease or cancer, epidemiological studies show that there are lower cancer rates in people whose diet are rich in fruits and vegetables. The difference between the clinical trials in the epidemiological studies may be that in the clinical trials the participants were taking anti-oxidant supplementation while in the epidemiological studies the individuals were eating raw fruits and vegetables.
However, it is known that antioxidants do play a role in slowing the aging process because of the role they play in fighting free radicals. New data from ongoing studies will available in the next few years. The best advice at this time is to eat a diet that is well balanced and high in raw fruits and vegetables.
(1) Alcohol Research and Health: Alcohol, Oxidative Stress and Free Radical Damage
(2) Ohio State University: The Free Radical Theory of Aging
(3) Biotechnology Research International: DNA Damage Protecting Activity and Free Radical Scavenging Activity of Anthocyanins from Red Sorghum (Sorghum bicolor) Bran
(4) MedlinePlus: Antioxidants
(5) Circulation: Antioxidant Consumption and Risk of Coronary Heart Disease: Emphasis on Vitamin C, Vitamin E, and ß-Carotene
(6) National Cancer Institute: Antioxidants and Cancer Prevention