| Anti-Oxidants & You
By:
Ms Lita Chew, Manager, Oncology Pharmacy, NCC
What are anti-oxidants?
Normal body functions, such as breathing or physical activity, as well as other lifestyle habits such as smoking and drinking alcohol. preface damaging oxygen particles called free radicals that attack healthy cells. When your cells are weakened by free radicals, they may be more susceptible to developing certain types of cancers.
Anti-oxidants are compounds that destroy oxygen free radicals. Many of these compounds are present in the diet as vitamins. The best known anti-oxidants are vitamin A, vitamin C and vitamin E.
Getting the right amount of anti–oxidant vitamins
The best way to get anti-oxidant vitamins into our body system is through healthy eating habits. Fruits and vegetables contain essential vitamins, minerals, fibers and other nutrients including anti oxidants. A good start to optimal health is to eat at least 5 servings of fruits and vegetables a day (you can think of a “serving” as about a fistful). Individuals who consume diets rich in fruits and vegetables may have a reduced risk of cancer compared with those who eat a much higher proportion of high-fat and processed foods.
Anti-oxidant vitamins in cancer prevention studies
Numerous studies have examined the association between dietary anti-oxidant intake and the risk of cancer. The results of recent studies are summarized below. As shown, a major surprise of these studies has been that anti-oxidant supplementation actually appears to be harmful in some disease groups.
Anti-oxidant Supplementation and Cancer Prevention: Randomized Trials
EXPERIMENTAL
INTERVENTION
|
SAMPLE
SIZE
|
DURATION OF STUDY |
CHARACTERSTICS OF PARTICIPANTS |
STUDY
OUTCOME
|
ß-Carotene 15 mg/day
Vit E 30mg/day
Selenium 50mcg/day
|
29,584 |
6 years |
Malnourished
Age: 40-69
|
Lower cancer rate |
ß-Carotene 20 mg/day compare to tocopherol 50 mg/day
|
29,133 |
5-8 years,
average 6 years
|
Male smokers
Age: 50-69
|
ß-Carotene 20 mg/day associated with increase in
lung cancer.
|
ß-Carotene 30 mg/day and Retinyl palmitate
25 000IU/ day
|
18,314 |
4 years |
Male and female
Age: 45-74
Smoker and /or occupational exposure to asbestos
|
No clear evidence of benefit. Associated with more death. |
| ß-Carotene 50 mg/day on alternate days |
22.071 |
11.6 – 14.2 years,
average 12 years
|
Male
Age: 40-84
Current/former or non smokers
|
No clear evidence of benefit of harm on risk of getting cancer. |
| ß-Carotene 50 mg/day on alternate days |
9,876 |
0.00-2.72 years, median 2.1 years
|
Female
Age: > = 45
|
No significant difference in incidence of cancer. |
ß-Carotene 25 mg/day
Vit C 1000mg/day
Vit E 400IU/day
|
864 |
4 years |
Adenoma diagnosed
Good health < 80 years
|
No clear evidence of benefit |
| ß-Carotene 50 mg/day |
1,805 |
5 years |
Patients had a recent non-melanoma skin cancer |
No clear evidence of benefit |
Should I take anti-oxidants?
It is not a good idea to take high doses of anti-oxidant nutrients as they may interfere with cancer treatment, so be sure to discuss them with your healthcare providers. If you decide to take anti-oxidants supplementation, here are some basic points to consider:
| - |
Do I need to think first about my total diet plan? |
| - |
Should I check first with my doctors? |
| - |
How reliable is the source and information of products? |
| - |
Does it sound too good to be true? |
| - |
Is it really likely to be worth the expense, or would I be better off spending my money in some other ways? |
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