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As seen on BCTV October 29/02
CANCER AND NUTRITION
Cancer is a complex disease resulting from an interaction of multiple
risk factors. Nutrition is believed to play a role in many different
cancers (1). Food is known to contain both cancer-causing agents as
well as protective agents. Food choices, eating habits, lifestyle and
methods of food processing can all influence your risk of getting cancer.
A good diet can help to keep your body and immune system healthy so
it is less vulnerable to cancer (2), and can also help to minimize exposure
to environmental carcinogens.
There is much controversy over specific dietary recommendations that
will help prevent cancer. The following are the general recommendations
from: The American Cancer Society (1), The Canadian Cancer Society (3),
The National Institute of Health (8), The World Cancer Research Fund
and The American Institute for Cancer Research (10).
General Recommendations:
- Achieve and maintain a healthy body weight and participate in regular physical activity.
- Choose predominantly plant-based foods.
- Consume a minimum of 5-10 servings of fruits and vegetables everyday, try to emphasize fresh, unprocessed foods.
- Wash, peel and trim fruits and vegetables.
- Limit alcohol consumption.
- Limit intake of total and saturated fat.
- Limit intake of salt and foods that are salted, cured and smoked.
- Avoid charring foods or excessive browning.
- Be sure to include high fiber foods in your diet.
As seen on the following tables, there is convincing evidence for increased cancer risk with:
Obesity - endometrium/kidney and possible breast cancer.
Salt and Salting - nasopharynx and possible stomach cancer
Alcohol - esophagus, liver, mouth, pharynx, larynx and possibly colorectal and breast cancer
Meat - possible colorectal cancer
Individual Factors Believed to Increase or Decrease the Risk of Developing Specific Cancers
It is very difficult to isolate individual factors that increase or decrease the risk of getting cancer. Many epidemiological and experimental studies have tried to answer these questions. This research has been reviewed and amalgamated by The World Cancer Research Fund and The American Institute for Cancer Research (10) and it is presented in the following two tables.
Nutritional Factors Associated with an Increased Risk for Specific Cancers
| |
Eggs |
Cooking Method |
Total and saturated fat |
Cholesterol |
Milk and Dairy |
Sugar |
Coffee |
Obesity |
Meat |
Salt and Salting |
Alcohol |
| Esophagus |
|
|
|
|
|
|
|
|
|
|
# |
| Lung |
|
|
# |
# |
|
|
|
|
|
|
# |
| Stomach |
|
# |
|
|
|
|
|
|
|
# |
|
| Pancreas |
|
|
|
# |
|
|
|
|
# |
|
|
| Gallbladder |
|
|
|
|
|
|
|
# |
|
|
|
| Liver |
|
|
|
|
|
|
|
|
|
|
# |
| Colo-rectal |
# |
# |
# |
|
|
# |
|
# |
# |
|
# |
| Breast |
|
|
# |
|
|
|
|
# |
# |
|
# |
| Ovary |
|
|
|
|
|
|
|
|
|
|
|
| Endometrium |
|
|
# |
|
|
|
|
# |
|
|
|
| Prostate |
|
|
# |
|
# |
|
|
|
# |
|
|
| Thyroid |
|
|
|
|
|
|
|
|
|
|
|
| Kidney |
|
|
|
|
# |
|
|
# |
# |
|
|
| Bladder |
|
|
|
|
|
|
# |
|
|
|
|
| Mouth and pharynx |
|
|
|
|
|
|
|
|
|
|
# |
| Nasopharynx |
|
|
|
|
|
|
|
|
|
# |
|
| Larynx |
|
|
|
|
|
|
|
|
|
|
# |
Legend |
# |
Convincing |
# |
Probable |
# |
Possible |
Adapted from: Food, Nutrition and the Prevention of Cancer: A Global Perspective, 1997.
World Cancer Research Fund and the American Institute for Cancer Research.
Nutritional Factors Associated with a Decreased Risk for Specific Cancers
| |
Vegetables |
Fruits |
Carotenoids in foods |
Vitamin C in foods |
Minerals in foods |
Cereals (grains) |
Starches |
NSP fiber |
Tea |
Refrigeration |
| Esophagus |
# |
# |
# |
# |
|
|
|
|
|
|
| Lung |
# |
# |
# |
# |
# |
|
|
|
|
|
| Stomach |
# |
# |
# |
# |
|
# |
|
|
# |
# |
| Pancreas |
# |
# |
|
# |
|
|
|
# |
|
|
| Gallbladder |
|
|
|
|
|
|
|
|
|
|
| Liver |
# |
|
|
|
|
|
|
|
|
|
| Colo-rectal |
# |
|
# |
|
|
|
# |
# |
|
|
| Breast |
# |
# |
# |
|
|
|
|
# |
|
|
| Ovary |
# |
# |
|
|
|
|
|
|
|
|
| Endometrium |
# |
# |
|
|
|
|
|
|
|
|
| Cervix |
# |
# |
# |
# |
|
|
|
|
|
|
| Thyroid |
# |
# |
|
|
|
|
|
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|
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| Kidney |
# |
|
|
|
|
|
|
|
|
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| Bladder |
# |
# |
|
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|
|
|
|
|
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| Mouth and pharynx |
# |
# |
|
# |
|
|
|
|
|
|
| Prostate |
# |
|
|
|
|
|
|
|
|
|
| Larynx |
# |
# |
|
|
|
|
|
|
|
|
Legend |
# |
Convincing |
# |
Probable |
# |
Possible |
Adapted from: Food, Nutrition and the Prevention of Cancer: A Global Perspective, 1997.
World Cancer Research Fund and the American Institute for Cancer Research.
Specific Chemicals that May Act as Potential Carcinogens and Anticarcinogens
There are many specific compounds found in foods that are believed to increase or decrease your risk of getting cancer. The following is a summary of some of these specific chemicals and their potential association with cancer. This information is a summary of opinions from the organizations and research studies referenced in this summary.
Potential Anticarcinogens
Phytochemicals: chemicals found in plants that may help to prevent cancer (6,3).
Phyoestrogens: estrogen-like chemicals found in plants that may protect against breast cancer; however most studies are inconclusive (6,3).
Lycopene: a chemical in tomatoes that may help to prevent cancer, although current studies are inconclusive (7,8)
Allium: A chemical found in garlic that may help to prevent cancer (2,9)
Isoflavones: A chemical found in soya beans that may help to prevent cancer, although current studies are inconclusive (6)
Antioxidants (vitamins C, E, beta-carotene, GSH, alpha-lipoic acid, SOD, catalase): are essential for good health and may help to prevent cancer (6); however, vitamin supplementation is generally not recommended (4).
Potential Carcinogens
Hot mate: A South American drink that possibly increases the risk of mouth, pharynx and esophagus cancers (5).
Nitrosamines: chemicals found in meat that are cooked at high temperatures, possibly cause an increased risk for stomach and colo-rectal cancers (2) also suspected as a cause of breast cancer (6).
Known Carcinogens
Afaltoxins: chemicals found in moulds (1,5).
Alcohol (4-Aminobiphenyl) (1)
Salt preserved fish Shale oils (1)
Tobacco products (1)
References
1. American Cancer Society. www.cancer.org. Accessed April 2002.
2. Blackburn GL, Go VL, Herber D, Holland JF, Cancer Treatment Foundation (US). Nutritional Oncology. San Diego: Academic Press. 1999.
3. Canadian Cancer Society. www.cancer.ca. Accessed April 2002.
4. National Institute of Health. www.nci.nih.gov. Accessed April 2002.
5. Potter, JD, World Cancer Research Fund, American Institute for Cancer Research. Food Nutrition and the Prevention of Cancer: A Global Perspective. American Institute for Cancer Research, Washington, DC. 1997.
6. Pence BC, Dunn DM. Nutrition and Women's Cancers. Boca Raton, Fla: CRC Press. 1998.
7. Giovannucci E, Rimm EB, Liu Y, Stampfer MJ, Willett WC. A prospective study of tomato products, lycopene, and prostate cancer risk. J Natl Cancer Inst. 2002 Mar 6;94(5): 391-8.
8. Imaida K, Tamano S, Kato K, Ikeda Y, Asamoto M, Takahashi S, Nir Z, Murakoshi M, Nishino H, Shirai T. Lack of chemoprotective effects of lycopene and curcumin on experimental rat prostate carcinogenesis. Carcinogenesis. 2001 Mar;22(3):467-72.
9. Milner JA. A historical perspective on garlic and cancer. J Nutr 2001. Mar;131(3s):1027S-31S.
10. Fong LY, Nguyen VT, Farber JL. Esophageal cancer prevention in zinc-deficient rats: rapid induction of apoptosis by replenishing zinc. J Natl Cancer Inst. 2001. Oct 17;93(20):1525-33.
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