Things you may want to know about antioxidants
Antioxidants are substances capable of inhibiting the oxidation of molecules normally caused by free radicals, and are credited to preventing some diseases or slow down the aging effect.
Q: In many health-related articles in newspapers, magazines and on television, it is often reported that free radicals are the culprits of the aging process and that's why we need to eat lots of food containing antioxidants. Then, what are the typical diseases caused by free radicals and what kind of antioxidants can prevent these negative effects?
A: As people get older, the most harmful diseases are explained to be a result of oxidation by free radicals. The serious ones include cancer, atherosclerosis, heart disease and cerebrovascular disease and dementia. For the purpose of prevention, vitamin A, betacarotin, vitamin C, vitamin E (tocopherol), Selenium, Lycopene, Coenzyme Q10 and numerous stand-alone products or mixtures of antioxidants in complex products are sold in various capacities.
Q: Among the antioxidants there are lots of different types of vitamins. So isn't it better to take one multivitamin every day rather than several single vitamins separately?
A: Multi-vitamins only contain the minimum dose of the daily required amount to prevent vitamin deficiency diseases. To get the antioxidant effect, many more antioxidant vitamins should be consumed than the daily required amount. For example, at least 40 times the daily required dose of vitamin E should be consumed and 10 to 100 times the amount of vitamin C should be taken to get the antioxidant effect. Therefore, taking common multivitamins will not be enough for the recommended antioxidant effect.
Q: So if I keep taking extra antioxidants, is cancer preventable?
A: Many scholars have expected positive results, but the actual results were very disappointing. Two large clinical studies with antioxidant beta carotene were conducted to see whether it could prevent lung cancer in smokers, but unfortunately there were more cases of lung cancer detected in people taking beta carotene. For the purpose of preventing gastrointestinal cancer, one study with vitamin A, beta carotene, vitamin C and vitamin E showed no advantage in preventing the disease but the people who took those antioxidants died earlier. Head and neck cancer patients took large amounts of vitamin E to prevent the recurrence of the cancer. But 4-5 years later, there were 2 times more recurrences of cancer, and 3 times more of other cancers. Therefore, the results so far indicate that antioxidants cannot be considered treatment for the prevention of specific cancer and instead increases some of them.
Q: How about for the prevention of heart disease and atherosclerosis?
A: One study showed that a group with typical antioxidant tocopherols (vitamin E) seemed to have more congestive heart failure. In addition, folic acid, vitamin B6, B12 - vitamins already known to have preventive effects on heart disease were given to patients with coronary stent insertion. But the restenosis rate was higher than the group not taking the vitamins. Therefore, antioxidants cannot prevent heart disease or atherosclerosis but conversely makes it worse.
Q: Antioxidants are thought to be good for health theoretically, why do the results more harm than good?
A: The reasons are not clearly identifiable.
Some theory indicates that antioxidants are only effective when they exist with other ingredients in harmony in actual food, so it is useless if it is taken alone in an extracted form. Another theory indicates that no matter how good antioxidants are, excessive doses can actually promote oxidation or some could just be mistaken as antioxidants. To be sure, it is not recommendable to take extra antioxidants but it is preferable to get them by eating a variety of foods such as fruits and vegetables.
Q: I am taking 2g of Vitamin C everyday because it is known to be good for fatigue, increase immunity and prevent colds. Is this in fact true?
A: The most publicized positive effects of vitamin C have not been proven in clinical studies. First, more than 200mg of Vitamin C cannot be absorbed a day and the rest would be pushed out of the body. Therefore, you don't need to take high doses of more than 1g of vitamin C. Yet if you can take 1g of vitamin C everyday for a long period, it will help you to recover more easily and quickly from a common cold.
The author is a clinical instructor at the Seoul National University Hospital International Healthcare Center (SNUH-IHC)