During the oxidative process, cellular membranes and other structures, such as proteins, lipids and DNA, are damaged. The process of oxygen metabolism produces unstable molecules called free radicals that are capable of stealing electrons from other molecules, damaging DNA and other cells in the process.
Some free radicals can be tolerated by the body, and they are needed for its proper functioning. Over time, an overload of free radicals can damage the body irreversibly and cause conditions such as heart disease, liver disease, and certain types of cancer (such as esophageal, stomach, and bowel cancer).
A variety of factors contribute to oxidation, including stress, cigarette smoking, alcohol, sunlight, and pollution.
Free radicals and antioxidants
Free radical damage can be prevented by eating foods that contain antioxidants, which neutralize them.
Among these are antioxidant nutrients, vitamins A, C, and E, and minerals copper, zinc, and selenium.
Vitamins and minerals are not believed to have the same antioxidant effects as other compounds in foods, such as phytochemicals in plants. Phytochemicals (such as lycopene in tomatoes and anthocyanin in cranberries) are known as nonnutrient antioxidants.
A free radical’s effect
Free radicals are responsible for the following conditions:
- Loss of vision resulting from the degradation of the eye lens.
- (Arthritis) Inflammation of joints.
- Brain damage (such as Parkinson’s or Alzheimer’s disease) occurs when nerve cells are damaged.
- Aging process accelerates.
- Free radicals increase the risk of coronary heart disease by causing LDL cholesterol to adhere to artery walls.
- A certain type of cancer is caused by damaged DNA in the cell.
Antioxidants that prevent disease
The intake of antioxidants may have the ability to reduce the risk of some diseases (such as cardiac disease and some cancers). In order to reduce or prevent the damage caused by oxidation, antioxidants destroy the free radicals in the body cells.
Around the world, antioxidants continue to be studied for their potential protective effects. In particular, men who eat plenty of the antioxidant lycopene (found in tomatoes) may have a lower risk of developing prostate cancer as compared to other men.
It has been proven that lutein, found in spinach and corn, can significantly reduce the incidence of age-related eye lens degeneration as well as associated vision loss in the elderly.
The low heart disease rates in Japan may be attributed to flavonoids (such as the catechins found in green tea).
Supplements containing vitamins and antioxidants
The evidence for the effectiveness of antioxidants coming from whole foods has been increasing, as opposed to antioxidants taken from isolated foods and then taken as tablets.
Certain vitamins can increase our cancer risk, according to research. It has been shown that vitamin A (beta-carotene) may reduce the risk of some cancers, but could increase the risk of others, such as lung cancer (if the vitamin is purified from food).
Taking vitamin E as a supplement didn’t offer the same benefits as taking it as a food. If antioxidant minerals or vitamins are consumed above recommended amounts for dietary intake, they can also act as pro-oxidants or damaging “oxidants”.
It is recommended that you consume antioxidants from whole foods as part of a well-balanced diet. Seek advice from your doctor or dietitian if you need to take a supplement and choose supplements which contain all the nutrients at the recommended levels.