Free radicals are atoms or molecules containing an unpaired or odd electron. They are highly reactive and unstable and combine with other molecules to form more stable products.
Our daily metabolism of fat, carbohydrates and proteins during energy production in the mitochondria produces free radicals. Sometimes, immune system cells create free radicals to neutralize harmful viruses and bacteria. Biological or emotional stress factors do generate free radicals. Low blood supply during heart attacks and strokes also form free radicals.
Environmental pollutants from auto exhaust, second-hand cigarette smoke, pesticides, or even ultraviolet radiation from the sun create free radicals in our bodies. These environmental free radicals then enter the body through the skin, respiration, drinking water, and other means. Studies also demonstrated that chemicals such as drugs, food additives, preservatives toxins, deep fried and spicy foods; and strenuous exercise, exhibit the ability to produce enormous amounts of free radicals. Toxic products found in furniture polish and paints eg, toluene, benzene and formaldehyde do produce free radicals.
Even oxygen can initiate a free-radical chain reaction in our bodies. During cellular respiration, some oxygen molecules are converted into oxidizing agents ( free radicals ) , such as superoxides or hydrogen peroxide.
Free radicals are very unstable and react quickly with other compounds, trying to capture or donate an electron in order to gain stability. Generally, they attack the nearest stable molecule. When the targeted molecule loses or gains an electron, it becomes a free radical itself, causing a chain reaction which cascades once initiated.
Fortunately, the body is able to curb free-radical damage by producing antioxidant molecules and enzymes. Antioxidants interact with free radicals and “quench” them, or render them harmless, by donating or stealing an electron. The body arsenal of antioxidants appears to be sufficient to keep oxidation in check in children and youth. In adults the effectiveness of the body’s antioxidant defense mechanisms appears to have lessened, and free radicals are given greater rein to do damage.
Normally, the body is able counteract free radicals However, when antioxidants are too few in number or unavailable, or if the free radical production becomes excessive, damage can occur. Free radicals kill cells, destroy enzymes and produce toxic chemicals. It is estimated that every cell in our body is attacked by free radicals thousands of times a day.
This activity has been implicated in a number of chronic diseases. Significant damage can lead to a variety of degenerative diseases such as arthritis, kidney disease, cataracts, colitis, lung dysfunction, pancreatitis, skin lesions, central nervous system injury, gastritis, tumor promotion, carcinogenesis, Alzheimer’s disease and aging, to mention a few. The main danger comes from the molecular reaction with important cellular components such as DNA or cell membranes. DNA targeted by a free radical can activate ‘bad genes’ that would otherwise have lain dormant. Cells under attack may function poorly or die if this occurs. Of particular importance is the fact that free radical damage accumulates with age.
Antioxidants are molecules which can safely interact with free radicals and terminate the chain reaction before vital molecules are damaged. Antioxidants neutralize free radicals by donating one of their own electrons, ending the electron-stealing reaction. The antioxidants themselves don’t become free radicals because they are stable in either form.
The human body can produce antioxidants. Superoxide dismutase (SOD), catalase, and glutathione peroxidase are enzymes produced by the body to defuse free radicals. In addition , many vitamins and minerals act as powerful antioxidants Included among these components are vitamin E( tocotrienols and tocopherols), vitamin C, beta-carotene, lycopene, vitamin B2, and vitamin B6.
Performance of intense physical activities (eg marathons) can increase oxygen consumption by 10- to 15 times over a resting state in order to meet energy demands. Elevated oxygen consumption produces “oxidative stress” that leads to the generation of free radicals. Furthermore, the fuelling of strenuous physical exercise requires increased calories, particularly carbohydrates, and consequently produces more free radicals. As such, athletes should ensure a high intake of antioxidant nutrients to help the body address the free radicals produced during high-intensity exercise. Bolstering antioxidant defences may alleviate exercise-induced damage to muscles and other tissues.
Atherosclerosis is a condition where the artery walls are narrowed by deposits of plaque, eventually blocking off the flow of blood. The plaque mainly consists of cholesterol, other fatty substances and calcium.
Oxidized low-density lipoprotein is atherogenic and believed to contribute to the development of atherosclerosis. As such, supplementation with antioxidants may reduce the risk of atherosclerosis. Vitamin E may slow the progression of atherosclerosis by blocking oxidative modification of low-density lipoprotein cholesterol and thus decreasing uptake into the arterial lumen.
Japanese scientists have demonstrated that oxidative stress damages the insulin producing cells of the pancreas. As a result, the ability to control blood sugar is reduced when the level of free radicals is high. There is also a significant correlation between high blood sugar levels and depletion of antioxidants. Therefore, consumption of antioxidant nutrients may help to reduce the risk of diabetes as well as diabetes complications, including kidney damage, nerve damage, diabetic foot syndrome (which may necessitate amputation), eye disease and blindness.
Intuitively, we understand that aging causes hair to thin and turn grey, skin to become wrinkled, less elastic and saggy, and our memories to forget things we used to remember. In the aging process, there is a slowing down of organ function, diminished production of digestive enzymes and a reduction in the body’s ability to break down and absorb nutrition . Normal aging also brings about other changes such as loss of peripheral vision, loss of hearing acuity, decreased taste buds, increased frequency of urination, loss of the structures connecting nerve cells in the brain, muscle mass decline, slow nail growth, insomnia, and stiff, painful joints. One theory suggests that free radical damage causes aging,. and that aging and disease are inextricably linked. Because antioxidants are capable scavengers of free radicals, they are able to slow down the aging process, reducing susceptibility and delaying onset of life-threatening diseases.