DIET AND CANCER
Introduction
Cancer is a diseases characterized by uncontrolled cell division and the ability of these cells to invade other
tissues, either by direct growth into adjacent tissue through invasion or by implantation into distant sites by metastasis.
Metastasis is the stage in which cancer cells are transported through the bloodstream or lymphatic system. Cancer affects
people at all ages, but risk tends to increase with age, due to the fact that DNA damage becomes more apparent in aging DNA.
Cancer is one of the principal causes of death in developed and developing countries. (Wikipedia, 2003)
Many types of cancer exist. Severity of symptoms depends on the site and character of the malignancy and whether there is
metastasis. A definitive diagnosis usually requires the histologic examination of tissue by a pathologist. This tissue is
obtained by biopsy or surgery. Most cancers can be treated and some can be cured, depending on the specific type, location,
and stage of that specific cancer. Once diagnosed, cancer is usually treated with a combination of surgery, chemotherapy and
radiotherapy. With the development of research and technology, treatments are becoming more specific for the type of cancer
pathology. Drugs that target specific cancers already exist for several cancers. If untreated, cancers may eventually cause
illness and death. (Kleinsmith, 2006)
The unregulated growth that characterizes cancer is caused by damage to DNA, resulting in mutations to genes that encode for
proteins controlling cell division. Many mutation events may be required to transform a normal cell into a malignant cell.
These mutations can be caused by:
- Chemicals or physical agents called carcinogens
- Close exposure to radioactive materials
- Certain viruses inserting their DNA into the human genome
Mutations occur spontaneously, and may be passed down from one generation to the next as a result of mutations within germ lines.
Many forms of cancer are associated with exposure to environmental factors such as tobacco smoke, radiation, alcohol and
certain viruses. Some of these risk factors can be avoided or reduced but in general terms it is an unavoidable disease. (Ralph, 1989)
The risk of cancer is affected by certain factors. They include:
1. Genetic factors
People who have a family history of a particular cancer are more likely to develop it themselves.
2. Environmental factors
A range of environmental factors affect the development of a large proportion of cancers, to varying degrees. Examples are tobacco smoke, diet, alcohol, some chemicals, and many other aspects of lifestyle e.g. physical activity and body weight.
A large proportion of cancers are influenced by environmental factors:
- some forms of cancer are more common in countries that have particular habits, e.g. stomach cancer is more common in parts of China where there is a high consumption of salted foods
- people who move from one country to another have a greater risk of the cancers more commonly seen in the country they move to (after a period of time): this is probably due to changes in diet and lifestyle
- groups of people who have a very different lifestyle from others in a community tend to have different patterns of cancer, e.g. religious groups.
3. Hormonal Factors
The risk of some cancers e.g. some breast cancers is linked to levels of certain hormones in the body. (Healthy eating, 2006)
4. Diet
Diet has a greater influence on some types of cancer than others. The strongest links are with some cancers of the gastrointestinal
tract e.g. of the mouth, throat, stomach and large bowel (colon) and some hormone-related cancers e.g. breast. Approximately 30% of cancers
could be prevented by dietary means in Western countries. It is estimated that a fifth to a third of the incidence of several of the most
common cancers could be prevented by maintaining a healthy body weight and being physically active. (Diet and cancer prevention, 1998)
Diet plays a major role in causing cancer. The consensus on diet and cancer is that obesity increases the risk of developing cancer. Particular
dietary practices often explain differences in cancer types. Examples of cancers are:
- Gastric (Stomach) cancer caused by a diet high in salt and smoked or cured foods.(stomach cancer,2003)
- Colon (bowel) cancer caused by diets high in fat and cholesterol (colon cancer,2003)
Mainly, immigrants are at higher risk of developing gastric and colon cancer which states that there is a link between diet and cancer rather than a genetic basis.
Vegetarians and vegans are at very low risk of getting cancer. The less animal source of food, the lower the rate of cancer. (Harris, 1999 )
Examples of foods which assist in prevention of cancer include:
- Fibre
- Vitamins A, C, E and D
- Certain types of oils found in fish
- Fruits and vegetables
Examples of foods which cause cancer include:
- Fats (especially animal fats)
- Red and processed meats
- Alcohol
5. Additives
To commercially prepared foods many different substances are added which play a major part in causing cancer. Some additives stop food from
going off and so can help to keep us healthy. A toxin called aflatoxin that comes from a mould which grows on stored food in hot and humid
countries, especially on peanuts is used as an additive. This causes liver cancer as it is carcinogenic to humans and animals as well. Other
additives that can cause cancer are pickled foods which may increase risk of cancer of the stomach and oesophagus (gullet), particularly if
they are very salty. Some additives such as colours, flavours and sweeteners are not considered as cancer causing agents. Saccharin, an
artificial sweetener, was once claimed to be a carcinogen.
6. Contaminants
Nitrosamines, chemicals found in cured meats and beer are carcinogenic to humans which cause cancer. Smoking and barbecuing foods causes
formation of chemicals called polycyclic aromatic hydrocarbons which cause cancer. Cooking over a high heat could increase the risk of cancer
Frying and baking meat at high temperatures creates chemicals called heterocyclic amines which increase risk of bowel or oesophagus cancer.
Acrylamide, a chemical found in foods such as crisps and chips may also be a source of causing cancer.
7. Obesity
Obesity can increase your risk of:
- Breast or uterine (womb) cancer if you are a woman
- Colon (bowel), oesophageal, kidney and gallbladder cancer
Breast cancer is hormone linked whose development is affected by amounts of the sex hormones; oestrogen and testosterone. Fatty tissue
produces an enzyme called aromatase which affects the balance between these hormones thus obesity causes breast cancer. Risk of breast cancer
increases strongly with age, and being obese increases the risk of several cancers.
Obese people may have increased risk of bowel cancer because they tend to have higher blood sugar levels as they are resistant to insulin.
Nutritional tips for anti-cancer
- Pectin, the fiber in apple skin, is fermented in the intestines, producing short- chain fatty acids that prevent the growth of harmful bacteria. They also nourish the cells of the intestinal lining, making them more resistant to becoming cancerous.
- Antioxidants, such as vitamin C and E and beta carotene, seem to have a synergistic effect when taken together. So, eating lots of fruits and vegetables in a salad together produces a greater anti-cancer effect than eating each one individually.
- The isoflavone in soy that has the most potent anticancer properties is genistein
- Whether or not natural vitamin E from foods or the factory-made vitamin is biologically better, yet the natural vitamin E may be more biologically active. Natural vitamin E is recognized on the package label by the "d" prefix or "d-alpha tocophenol;" the synthetic compound will have a "dl" prefix.
Anti-cancer vegetables:
- broccoli
- Brussels sprouts
- cabbage
- carrots
- cauliflower
- eggplant
- green beans
- kale
- onions (red)
- peppers
- radishes
- soy
- squash
- sweet potatoes
- tomatoes
- yams
Anti-cancer fruits:
- apricots
- blueberries
- grapefruit
- grapes
- lemons
- mangoes
- oranges
- papayas
- peaches
- persimmons
- strawberries, organic
- tangerines
- squash
Anti-cancer nutrients:
- Vitamin D
- Selenium
- Acidophilus
- Garlic
- Green Tea
(The anti-cancer diet, 2006)
Reducing cancer through a healthy diet
The diet thought to help reduce cancer risk is much the same as that recommended for a
healthy heart. To prevent or rather reduce the risk of cancer, one should:
- less meat and animal fats (butter, cream, cheese)
- five portions of raw or lightly cooked fruit and vegetables every day (5 portions is about 400g or 1lb in weight
- Increase Your Fiber Intake.
- more oily fish (eg salmon, trout, mackerel)
- less salt, salty foods, sugar and sugary foods
- more cereals, bread, pasta and rice
- Eat lots of raw fruits and vegetables
- Switch from red meat to seafood
- Switch from an animal-based diet to a plant-based diet
- Eat more soy products
- Eat foods containing calcium
- Eat other anti-cancer nutrients
- unfried foods and if you use fats in cooking, choose vegetable oils or olive oil not lard or butter
- Drink less alcohol
(Diet causing cancer, 2002)
Signs and symptoms
- Persistent cough or blood-tinged saliva - lung head and neck cancer.
- A change in bowel habits: pencil-thin stools or diarrhoea - colon
- Blood in your stool – bowel cancer
- Unexplained anaemia - bowel cancer
- Breast lump or breast discharge - breast cancer
- A change in urination - prostate cancer
- Hoarseness – throat cancer
- Obvious change in a wart or a mole - skin cancer
- Indigestion or difficulty swallowing – oesophagus cancer
- Unusual vaginal bleeding or discharge - uterus cancer
- Nonhealing sores
- Back pain, pelvic pain, bloating, or indigestion – ovarian cancer
(Buechler ,2003)
Cancer diagnosis
Most cancers are initially recognized either because signs or symptoms appear or through screening.
Treating cancer
Cancer can be treated by:
- surgery
- chemotherapy
- radiation therapy
- immunotherapy
- monoclonal antibody therapy
Limitations to treatments of cancer
Surgery could enhance complete removal of the cancer without damage to the rest of the body is the goal of treatment. , but the propensity of
cancers to invade adjacent tissue or to spread to distant sites by microscopic metastasis often limits its effectiveness. The effectiveness of
chemotherapy is often limited by toxicity to other tissues in the body. Radiation can also cause damage to normal tissue.
Darrell Berg-Smith, CEO of DBS Worldwide Marketing Co., Ltd. He is a speaker, author, consultant and entrepreneur who specializes in teaching
low cost, high impact marketing and business building resources to businesses worldwide. You can get lots of free articles and resources at
www.DarrellBerg-Smith.com
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www.LandofSmilesFoundation.org
References
Cancer http://en.wikipedia.org/wiki/Cancer#Nomenclature_and_classification
Kleinsmith, LJ (2006). Principles of Cancer Biology Pearson Benjamin Cummings.
Jay R 2003 Stomach cancer
http://hcd2.bupa.co.uk/fact_sheets/html/stomach_cancer.html BUPA's Health Information Team
Tony J 2006 Diet and cancer prevention,
Nutritional Aspects of the Development of Cancer, Health and Social Subjects report British Nutrition Foundation {accessed 22/10/06}
Donna M 2003 Causes of Colon Cancer [online] available:http://coloncancer.about.com/od/causesofcancer/a/Colon_Cancer.htm {accessed 27/10/06}
William Harris, M.D. 1999 Cancer and the Vegetarian Diet
[Online] available: http://www.vegsource.com/harris/cancer_vegdiet.htm {accessed 21/10/06}
Family Nutrition, THE ANTI-CANCER DIET 2006 http://www.askdrsears.com/html/4/T040300.asp
Cancer help UK Diet causing cancer 2002 http://www.cancerhelp.org.uk/help/default.asp?page=120#foodadd
Cancer Signs and Symptoms 2003 Mary Buechler
http://www.emedicinehealth.com/cancer_symptoms/page2_em.htm
Ralph W. Moss, Ph.D Galen on Cancer - How Ancient Physicians Viewed Malignant Disease 1989
