Oxidative stress is essentially an imbalance between the production of free radicals and the ability of the body to counteract or detoxify their harmful effects through neutralization by antioxidants.
Free radicals are formed when oxygen interacts with certain molecules. Once formed these highly reactive radicals can start a chain reaction, like dominoes.
Free radicals may become a danger to our body if they react with important cellular components such as DNA, or the cell membrane. Cells may function poorly or die if this occurs. Poorly functioned cells may cause chronic inflammation, which may eventually result in tumours and cancer.
To prevent free radical damage the body has a defence system of antioxidants.
Antioxidants will neutralise free radicals. The principle micronutrient (vitamin) antioxidants are vitamin E, beta-carotene, and vitamin C.
Oxidative stress occurs when free radicals are too numerous for antioxidants to adequately neutralize. Environmental pollutants, toxins, medications, infections, poor diet and radiation are all factors that contribute to the likelihood of this free radical/antioxidant imbalance.
Damages caused by oxidative stress
Some serious conditions include Parkinson's disease and Alzheimer's disease, gene mutations and cancers, chronic fatigue syndrome, fragile X syndrome, heart and blood vessel disorders, atherosclerosis, heart failure, heart attack and inflammatory diseases.
Some other conditions due to oxidative stress include ageing, wrinkles and greying hair.
How to prevent oxidative stress
The body cannot manufacture antioxidants, so they must be supplied in the diet.
Vitamin E : d-alpha tocopherol. A fat soluble vitamin present in nuts, seeds, vegetable and fish oils, whole grains (esp. wheat germ), fortified cereals, and apricots. Current recommended daily allowance (RDA) is 15 IU per day for men and 12 IU per day for women.
Vitamin C : Ascorbic acid is a water soluble vitamin present in citrus fruits and juices, green peppers, cabbage, spinach, broccoli, kale, cantaloupe, kiwi, and strawberries. The RDA is 60 mg per day. Intake above 2000 mg may be associated with adverse side effects in some individuals.
Beta-carotene is a precursor to vitamin A (retinol) and is present in liver, egg yolk, milk, butter, spinach, carrots, squash, broccoli, yams, tomato, cantaloupe, peaches, and grains. Because beta-carotene is converted to vitamin A by the body there is no set requirement. Instead the RDA is expressed as retinol equivalents (RE), to clarify the relationship. (NOTE: Vitamin A has no antioxidant properties and can be quite toxic when taken in excess.)