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What are Free Radicals? What are Anti-Oxidants?
Research has now proved that oxidation in the body cells (the process by which we are continuously burning our calories to get energy) releases dangerous, very active molecules known as free radicals. Oxygen while is essential for our survival, is very reactive atom and can potentially combine with other molecules damaging them – we call free radical.
These free radicals attack neighbouring cells (the cell walls and genetic material DNA within the cells) and over a long time period, can cause irreversible damage like mutation, decrease in brain function and sometimes cause diseases like cancer. Generally it manifests old age symptoms like lack of energy, poor memory, loss of hearing and falling hair, which are definitely associated with damaged or weak cells. Free radicals, in alcoholics, cause alcohol induced liver damage, perhaps more than alcohol itself. Free radicals in cigarette smoke have been implicated in inactivation of alpha-1 antitrypsin in the lung, which promotes the development of emphysema and it is now proved that these free radicals are the main culprit. While nature has created this problem, it has provided the solution as well.
The presence of compounds, called anti oxidants, in the system can mop up free radicals before they damage other essential molecules. An antioxidant is a chemical that prevents oxidation of other chemicals. Consuming more antioxidants helps provide the body with tools to neutralize harmful free radicals. It is estimated that there are more than 4000 compounds in food that acts as antioxidants. The most studied include Vitamin C and Vitamin E, beta-carotene and mineral selenium.
Besides antioxidants, there are several enzyme systems within the body that scavenge free radicals. Glutathione peroxidase, catalase, and superoxide dismutase (SOD) are such enzymes present in body which have antioxidant properties. However they require other micronutrient and minerals like selenium, iron, copper, zinc, and manganese for their functioning. Additionally, selenium, a trace metal that is required for proper function of one of the body’s antioxidant enzyme systems, is sometimes included in this category. The body cannot manufacture these micronutrients so they must be supplied in the diet.
The following vitamins have shown positive antioxidant effects: vitamin A or Retinol, or beta carotene found in carrots, tomato, squash, sweet potato, peaches and apricots are particularly rich sources of beta carotene; Vitamin C also called ascorbic acid found in citrus fruits like orange, lime, etc, green peppers, green leafy vegetables, strawberries, raw cabbage, tomatoes and potatoes; Vitamin E is found in wheat germ, nuts, seeds, whole grains, green leafy vegetables, vegetable oil, fish liver oil; and selenium found in fish, shell fish, red meat, grains, eggs, chicken and garlic. Vegetables are also good source if grown in selenium rich soil.
Vitamin C is the most important water-soluble antioxidant and can be found in fluid outside body cells. It neutralizes free radical in extracellular fluids before it can damage cell. On the other hand Vitamin E is the most important fat soluble antioxidant and is present in lipid /fat walls of the cell. It is seen as chain-breaking antioxidant inside the cell. Vitamin E protects cell membrane from oxidation. Beta carotene and other carotenoids works in tandem with Vitamin E.
Plants also contain various other substances which we today know as phytonutrients which are capable of removing free radicals. Various flavoniods, phenols etc fall in this category. Green tea which is known as good antioxidant is rich in such phytonuetrient – flavonoids.
What are Natural Sources of Antioxidants?
- The coloured stuff: carrots, apples, orange, tomatoes (cooked), beet, brinjal, dark green vegetable, olives, strawberries, honey and others.
- The tasty stuff: garlic, ginger, onion, nutmeg
- The smelly stuff: Tea, green tea, spinach, basil and other herbs etc.
Usually, the body’s natural defence system neutralizes free radicals that develop, rending them harmless. However, environmental assaults on the body, like UV radiation, pollutants and alcohol, can overpower the body’s ability to neutralize free radicals, damage the structure and functioning of body cells. There is good evidence that this damage contributes to aging and leads to host of diseases like cancer, arthritis, heart diseases. Regular exercise and eating more fruits or vegetables will vitalize inherent antioxidant systems and that your diet is providing the necessary components.
Antioxidant Supplements: Good or Bad?
Increasing awareness about Antioxidants has resulted in market flooded with various supplements having antioxidant properties. However there is no long term stable alternative to antioxidant rich daily diet.
Antioxidant supplements should only be recommended to people with old age, athletes with high metabolism, cancer patients and people with other disorders. Antioxidant dietary supplements in your quest to stay eternally young are often used as anti aging supplements. However they are no magic cure. Clinical studies have also shown harmful effects of excess consumption of these artificial antioxidants supplements.
The National Health and Nutrition Examination Survey (1999–2000 and 2001–2002) estimated amount of consumption of antioxidants US adults. Surprisingly high percentage of US adults has antioxidant supplements – mainly Vitamin C and Vitamin E.
For more information about the safety of dietary supplements, see the National Center for Complementary and Alternative Medicine (NCCAM) fact sheet Using Dietary Supplements Wisely. National Center for Complementary and Alternative Medicine mentions on its website – “Why Don’t Antioxidant Supplements Work?”