talk given by Maitree Suttajit, Ph.D., Faculty of Medicine, Chiang Mai University
Free radicals are highly charged and active particles which are made of unstable molecules or atoms due to their single and unbalanced electrons. The common free radicals are oxygen reactive species (ROS), namely, superoxide radical, hydroxyl radical, and peroxyl radical which can be internally produced by cellular metabolism, inflammaiton by immune cells and externally by radiation, pharmaceuticals, hydrogen peroxide, toxic chemicals, smoke, alcohol, oxidized polyunsaturated fats and cooked food. They are unstable and through chain reaction can attack vital biomolecules (DNA, lipids, proteins) in cells and body fluids.They also weaken the cells in our bodies leaving us vulnerable to disorders and diseases such as ateriosclerosis, atherosclerosis, coronary heart disease, stroke, hypertension, emphysema, diabetes, cataracts, rheumatoid arthritis, nephritis, Alzheimer disease, cancer, AIDS, etc. Aging process is also a result of the oxidation by free radicals in the body.They are formed naturally , both internally by metabolism and externally by chemicals. These include alcohol consumption, drugs, toxic metals, emotional stress, smoking, pesticides, herbicides and air pollutants.
Fortunately, nature provides us with plenty of "protecting molecules" or the so called "antioxidants" which can trap or destroy free radicals and subsequently protect us from damage due to the oxidative stress. There are two groups of natural antioxidants. The first group are our body enzymes such as superoxide dismutase (SOD), catalase, glutathione peroxidase. Wheat and barley grass products are rich in SOD. The other group are nutrient antioxidants which are vitamin E, vitamin C and beta-carotene (the pre-form of vitamin A). Selenium is also an important mineral antioxidant. In addition, there are still numerous other antioxidants such as bioflavonoids , carotenoids (such as lutein and lycopene) and phenolic compounds. Selenium is commonly found in onions, garlic, mushrooms, whole grain cereals, particularly in the wheat germ and rice bran.
Prevention is better than cure. The more toxic chemicals which produce free radicals we obtain, the more antioxidants in our diet we have to consume for the detoxification. We should be healthy and free from disease by preventing our body from any oxidative damage. In order to protect our better health or slow our aging, we should carefully avoid those factors which increase the production of free radicals; and daily eat more fresh vegetables and fruits, at least one pound or 400 grams, as well as sufficient amounts of nuts, seeds and pulses.
Plant food contains a wide range of phytochemicals and antioxidants which are protecting agents against free radicals. Beta-carotene are common in dark green, yellow, orange and red vegetables and fruits such as carrots, pumkin, tomatoes, spinach, peppers, watercress, broccoli, cherries, peaches, papaya, water melon and apricots. Several tropical fruits and vegetables are good sources of antioxidants. Vitamin C: all fresh fruits and vegetables, particularly citrus fruits; melon, strawberries, leafy green vegetables and tomatoes. Vitamin E all whole-grain cereals including brown rice, oats, wholemeal bread, wheat germ, soya beans, cold-pressed vegetable oils, nuts and seeds, parsley, brocolli and asparagus. In conclusion, if we can control free radicals , then we can reduce the degenerative diseases. Vegetarians have an advantage over non-vegetarians, because they eat a large variety of fresh vegetables, fruit and whole grains.