Colorectal Cancer Association of Canada - CCAC

Cancer Prevention > Preventing Colorectal Cancer  


Colorectal cancer is a devastating disease that invades the large intestine of approximately 22,000 Canadians each year. To remedy this cancer, most people undergo painful surgeries and invasive chemotherapy/radiation regiments designed to keep the cancer at bay. It is a cancer that presents no signs and symptoms early on, and can grow undetected long before a problem is noticed. And when symptoms do occur – diarrhea, vomiting, weakness, unexplained weight loss, bloody stools – they are not much different from symptoms of other cancers: these symptoms are very vague and indicative of a vast number of other illnesses as well.

Colorectal cancer does not discriminate, and even the healthiest individual can develop the disease. However, there are several lifestyle factors which you can control to help prevent this ailment. And in light of the alternatives listed above, we at least owe it to ourselves to make a concerted effort on how to effectively preempt this cancer’s onset. This section describes lifestyle factors and how they can be modified or implemented to reduce your risk of developing colorectal cancer. Though still a tad foggy, a light has been able to penetrate the deep recesses of our clouded understanding about colorectal cancer prevention, a lighthouse shines in the dusk, guiding the vessel of our comprehension through emerging research that is offering up weapons in the battle against this life-threatening cancer. There are steps that can be taken to prevent colorectal cancer and the following is a list of the 8 topics dealt with in this section:

Diet Nutrition/Supplementation Body Weight/Body Mass Index Exercise Metabolic Syndrome Smoking Alcohol Screening
NB: Prior to making any change in diet, exercise or introduction of supplements, a consultation with your physician is recommended.


By and large, the number one cancer that one can prevent through diet is colorectal cancer. Studies have revealed that a healthy balanced diet that includes a variety of fruits and vegetables, whole grains, lean protein, lower fat milk products and healthy fats has been linked to a decreased risk of colorectal cancer. Conversely, a diet high in fat and calories, low in fibre, vegetables and fruits and eating too much red meat and processed meats,has been linked to an increased risk of the disease.

For more information on diet and gastro intestinal health:

Diet : risk factors you can change:

1. 1. Fruits & Vegetables: Consume a diet high in a variety of fruits and vegetables. A recent study (Nomura, 2008) concluded that eating more fruits and vegetables protected men from colorectal cancer and past similar studies showed the same protective effects in men and women (Park 2007, Kouskik 2008). Green, leafy vegetables such as broccoli and spinach are highly recommended for their nutritional content and whole fruits are excellent sources of carbohydrates to consume. They contain important antioxidants (see below), minerals, and vitamins that are essential for our existence. Even though they are sweet, they contain fructose sugar which is both low glycemic (see #6 below) and has a low glycemic load (see #6 below).

2. Grains/Legumes: Replace refined grain food products made of white flour to whole grain food products made of whole grains such as oats, barely, and whole wheat; or consume these grains in their natural form. Refined sugars and grains have been stripped of their nutritional value and stand to increase the glycemic load (see #6 below) of a meal . Examples of legumes are beans, lentils and chickpeas. Whole wheat pasta, spelt pasta, spelt bread, oat bran breads, sourdough rye, long grain rice are just a few examples of unrefined grain products.

3. Milk: A review of nutrition and cancer by the World Cancer Research Fund and the American Institute of Cancer Research concluded that: “There is enough evidence to conclude that milk may protect against colorectal cancer. (World Cancer Research Fund/ American Institute for Cancer Research. Food, Nutrition, Physical Activity, and the Prevention of Cancer. A Global Perspective. Washington, DE: AICR, 2007.)The components in milk products that may account for this beneficial effect come from two key nutrients - calcium and vitamin D. However other milk components may also be involved (Pufulete 2008). Research to date suggests a synergistic effect between calcium and vitamin D in preventing colon cancer. (Grau al 2003) More specifically, it seems that the calcium in milk helps prevent, as well as moderate, the growth of benign polyps in your colon, one of the early signs of colorectal cancer. Vitamin D in turn appears to play a significant role in helping the body absorb the calcium. In addition, emerging research suggests that vitamin D may inhibit the growth of cancerous cells in the colon.

4. Red/Processed Meat: Limit your intake of red and processed meats because studies have identified cancer causing agents (carcinogens) not only in processed meat, but in a diet that is rich in red meat (ie beef, pork, lamb, veal) (Giovannucci et al 1994). Carcinogens are also produced when red meat is burnt during the cooking process and then subsequently ingested (Langman 2002). Consider alternative sources of protein such as poultry, low-fat dairy products, legumes, and fish (American Institute for Cancer Research – May 2008).

5. Water: Drink plenty of water to help your body’s digestive processes. Water provides a medium for biological reactions to occur in the body and chronic dehydration can contribute to a number of health problems including constipation, which is the inability to move the digestive contents through the bowels. Aiming to drink six to eight medium glasses of fluid daily can help to prevent sluggish bowels. Beverages such as tea, coffee, and fruit juices count towards fluid intake, and may bring with them other nutrients or benefits.

6.Trans Fats: Replace unhealthy fats called trans fats (found in cakes, cookies, fried foods, margarine, donuts, pastries and chips) and saturated fats (found in butter and red meat), with healthy fats called unsaturated fats (found in fatty fish like salmon, avocadoes, olive oil, and nuts). Recent studies (Vinikoor et al 2008) have suggested a link between trans fats and colorectal cancer risk and are therefore recommending that more healthy fats be introduced into the diet – those which are liquids at room temperature, specifically the mono and polyunsaturated fats. In contrast, the less healthy trans and saturated fats are typically solid at room temperature. To get more good fats in your diet, cook with oils, such as olive oil, and choose foods such as nuts, avocados and fatty fish over well done red meats. And cancer patients should consume no more than approximately 30% total calories from fat. For example, for a 2,000 calorie diet, this means eating no more than 67 grams of total fat per day. In general, the same principles that support heart health support the health of the colon as well. (Vinikoor et al 2008)

7. Sugar/Glycemic Index/Glycemic Load: Recent studies performed at Harvard Medical School found that men and women who consumed high amounts of foods that increased blood sugar levels had a higher chance of getting colorectal cancer in the future, compared to those men and women who ate lesser amounts of such foods. (Liu et al 2008) There is a large volume of scientific evidence showing the link between sugar and increased colorectal cancer risk. The Glycemic Index (GI) of a carbohydrate gives an idea of how quickly sugar levels in the blood rise after eating it. The index spans from 1 – 100, 100 representing the rate at which glucose is absorbed into the blood after ingestion. Those foods with the lower GI values will not spike blood sugar levels as quickly as those carbohydrates possessing higher GI values. For a list of GI values, visit The Glycemic Load is the weighted average glycemic index of the individual food multiplied by the amount of calories the food actually contains. For a list of GL values, visit . A study team at Duke University School of Medicine has suggested a possible reason why cancer cells like sugar so much.

In healthy cells, certain growth factors regulate their metabolism and cell survival. When these growth factors are removed, there is loss of glucose uptake and metabolism, and the cells die. However, cancer cells are able to maintain glucose metabolism by using a protein called Akt, which promotes glucose metabolism. This prevents cell death, even when the growth factors are not available. Consuming too much sugar causes our bodies to produce excessive amounts of insulin and insulin itself encourages the growth of cells, something which is good for healthy cells, but not cancerous cells. Avoid simple sugars: Processed and refined foods, including soft drinks, sugary beverages, candy bars, cakes, other desserts, as well as other snacks, contain high amounts of simple sugars. These are high GI foods, which can cause insulin levels to spike. (Flood et al 2007)


Oxidation and Antioxidant Rescue

When you burn food to create energy, you are essentially breaking chemical bonds. Sometimes the breaking of a chemical bond creates something called a free radical, which is missing an electron, which will seek out a stable molecule from which to steal an electron. The process is called oxidation and the process is considered to be a major factor in DNA damage, which not only causes cancer, but aging in general as well. Here is where the all powerful anti-oxidant comes in: they neutralize the free radicals before they can damage your DNA. Antioxidants which are found in fruits and vegetables and in nutritional supplements (vitamins and minerals) are bodyguards for your DNA. To help prevent colorectal cancer, having enough antioxidants on board to neutralize any free radicals that are created is ultimately the goal, because they inactivate free radicals, harmful molecules that are produced by the body and have been associated with the development of cancer (saffrey & stewart, 1997). Make certain that you eat plenty of antioxidant-containing foods (fruits and vegetables) to provide your DNA with plenty of protection from the wear and tear of daily life.

Several studies have suggested that the following specific antioxidant nutrients may reduce the risk of developing colorectal cancer:


Calcium is a mineral well-known for its role in bone health and prevention of osteoporosis, but it has also been shown to decrease the risk of developing colorectal cancer (Mizoue et al 2008). It is thought that calcium may have a protective effect on cells lining the bowel against carcinogens (cancer-causing substances) from the environment and from bile acid, a normal but toxic substance produced during digestion. Calcium is found in many foods such as dairy products (milk, yogurt, and cheese), green leafy vegetables, and fish like salmon and sardines. Vitamin D (below) aids in the body’s absorption of calcium. For adults aged 19-50, 1,000 mg of calcium per day is recommended from food, 1,200 mg for those over 50.

Vitamin D

Vitamin D is found in very few foods in nature, like egg yolks and fatty fish, but it is also produced by our skin when it is exposed to sunlight and has been shown to play an important role in the prevention of colorectal cancer (Wei et al 2008). Vitamin D is essential for calcium absorption and for aiding in the regulation of cell replication, which can go awry in cancer cells. Vitamin D is also added to some food products like milk and margarine. A small amount of sun exposure, without sunscreen, for just a few minutes a day can boost vitamin D levels. For adults, 1000 IU of vitamin D per day are recommended from a combination of food sources and minimal sun exposure. In the dark winter months, a daily 1000 IU supplement of vitamin D is recommended for adults (the supplement is recommended all-year round for the elderly, those with dark skin, and those who do not go outside often). Experts advise being mindful of time in the sun, as prolonged exposure can increase the risk of skin cancer.

Folate (Folic Acid)

Folate is a B vitamin found in many foods in nature like green leafy vegetables, beans, and citrus fruits. It is also added to grain products. The synthetic form of folate added to foods and found in supplements is called folic acid. Folate is crucial for the building and repair of cellular DNA; a lack of the vitamin can damage DNA and increase the risk of developing colorectal cancer (Duthie et al 2008). For adults, 400 mcg (micrograms) per day are recommended from food. Alcohol is known to interfere with the body’s absorption of folate, and drinking in excess (see alcohol section below for recommended allowances), can further increase the risk of colorectal cancer by greater depletion of folate.


Fibre is a substance found in all edible plants – fruits, vegetables, grains, legumes, etc. – that is not digested in the body. There is particular controversy over whether or not fibre itself decreases colorectal cancer risk. Recent research suggests that fibre from whole grains, fruits, and vegetables can decrease colorectal cancer risk (Jacobs et al 2007). Fibre adds bulk to the stool as it absorbs water; a soft, bulky stool stimulates the walls of the colon to move feces through quickly and easily. Fibre also absorbs carcinogens in the bowel, and combined with fast movement of stool, toxic substances come in less contact with the lining of the colon and rectum. There have been discussions about which type of fibre is the most beneficial. Fruit and vegetable fibre contains soluble, degradable constituents such as pectin and plant gum and is soluble in water to form a gel-like material. It can lower blood cholesterol and glucose levels. Examples can be found in oats, peas, beans, apples, citrus fruits, carrots, barley and psyllium. Whereas cereal fibre consists of insoluble, non-degradable components which promote the movement of material through your digestive system and increases stool bulk, so it can be of benefit to those who struggle with constipation or irregular stools. Examples can be found in foods such as whole-wheat flour, wheat bran, nuts and many vegetables. If feces are kept in the colon for a longer than average period of time, there is a chance that toxins may build up. For example, colonic bacteria produce toxic waste and colon cancer may be linked to prolonged exposure to these toxins. Hence, the timely and regular elimination of waste is always recommended. For that reason, according to researchers, insoluble fibre might display the most protective effects against colorectal cancer. For adults, 20-35 g of fibre per day is recommended from food.


Selenium is a trace mineral (required by the body in small amounts) that exists in soil and has been shown to decrease the risk of developing colorectal cancer (Jacobs et al 2004). It is found in many plants which absorb it and animals which consume the plants. The amount of selenium in food depends on the content of the mineral in the soil where plants grow and animals are raised. Soil in Canada and the US is generally rich in selenium and thus deficiency in the mineral is rare. Good sources of selenium are grain products, nuts, and poultry. In the body, selenium combines with proteins to form potent antioxidants. Antioxidants help protect cells from free-radicals, unstable molecules which can damage cellular DNA and lead to cancer. Selenium byproducts can also prevent cancer growth by activating tumour-suppressing genes. For adults, 55 mcg of selenium per day is recommended from food.

Omega-3 Fatty Acids

Omega-3 fatty acids are a type of unsaturated fat found in cold water, deep-sea fish and some plants, nuts, and oils such as kidney beans, walnuts, flaxseed, canola and olive oils. There are three types of Omega-3s, and fish contain the most readily absorbable forms, the greatest abundance being in fatty coldwater fish like salmon, tuna, and herring.

Evidence suggests a decreased risk of colorectal cancer associated with consumption of Omega-3s from fish (Geelen et al 2007, Pot et al 2008)). Omega-3s reduce inflammation in the body, including inflammation in the colon, which can lead to colorectal cancer. Getting more Omega-3s in the diet can also help reduce the impact of Omega-6s (another fat found in vegetable oils and baked goods). Omega-6s are important for health, but in excess can promote inflammation and lead to cancer (Pot et al 2008). Western diets are generally very high in Omega-6s. For adults, consuming at least two servings of fish (2-3 g of Omega-3s) per week is recommended.


Lycopene is a red pigment found in tomatoes and other such red colored produce such as watermelon, strawberries, guava, apricots, papaya and pink grape fruit: basically any fruit or vegetable that has a reddish/pinkish hue to it. Recently, its effects have been shown to decrease the risk of developing colorectal cancer (Tang et al 2008). The cancer combating antioxidant lycopene has been shown to inhibit the proliferation of colorectal cancer cells by suppressing an important signaling pathway that enables cancer cells to grow and survive. More than 80% of the lycopene consumed is derived from tomato products but processed foods (such as ketchup, tomato paste and spaghetti sauce) may be better sources of bioavailable lycopene than fresh tomato products. This is thought to be due to the breakdown of cell walls during processing and the presence of small amounts of fat, aiding in overall bioavailability (G’artner et al 1997). No recommended dietary allowance has been established for this nutrient.

Grape Seed Extract

Grape seed extract is a natural plant substance found in the seeds of grapes that has a concentrated source of oligometric proanthocyanidins (OPC) that protect cells from free radical damage and also promotes healthy circulation.

grapesGrape seed extract is also rich in polyphenols, a compound that is high in antioxidants and more powerful than vitamin C, E and beta-carotene. Many research publications have reported on the health benefits of grape seed extract including antioxidant activity, improved cardiovascular health, and gastric health; but recently, grape seed extract was reported to inhibit colorectal cell growth (Kaur et al 2008). Perhaps this may have something to do with the much highly publicized nutrient resveratrol, which is a polyphenol contained in grape seeds. Among its long list of possible therapeutic benefits, interfering with cancer cell growth and proliferation, as well as inducing cell death appears to be one of its greatest highlights, which may be contributing to some of the clinical benefits demonstrated by grape seed extract (Kundu et al 2008). There is no established recommended daily amount for grape seed extract but most research doses range from 50mg to 200mg per day. Debasis Bagchi, a leading grape seed extract researcher recommends daily dose of 50mg for ages 30-40 years, 100mg for ages 40-50 years and 200mg for adults older than 50 years.


Resveratrol is a compound that is found largely in the skins of red grapes. It is also found in other foods such as mulberries and peanuts. The resveratrol content of wine is related to the length of time the grape skins are present during the fermentation process. Thus, the concentration is significantly higher in red wine than in white wine, because the skins are removed earlier during white wine production, lessening the amount that is extracted. (Kopp et al 1998). Grape juice, which is not a fermented beverage, is not a significant source of resveratrol. A fluid ounce of red wine averages 160 mcg of resveratrol, compared to peanuts, which average 73 mcg per ounce. Red wine is the most notable dietary source.grapes

Recently, there has been a growing body of scientific evidence linking resveratrol to a range of beneficial health effects, including brain and mental health as well as cardiovascular health. Some of the newest research is associating resveratrol with decreased risk of developing colorectal cancer (Anderson et al 2006, Isidoro et al 2007). No recommended daily allowance of resveratrol has been officially set by any regulatory body as of yet. Hence, seeking the advice of your physician when wishing to ingest this nutrient or any other nutrient is highly advised. Drinking red wine in moderation (1 glass/day for women and 2 glasses/day for men) continues to be prudent and wise advice.

Coenzyme Q10

Coenzyme Q10 is a compound that is made naturally in the body. The body uses it for cell growth and to protect cells from damage that could lead to cancer. Studies have shown that coenzyme Q10 helps the immune system work better and makes the body better able to resist certain infections and types of cancer, including colorectal (NIH). There have been anecdotal reports (incomplete descriptions of the medical and treatment history of one or more patients) that coenzyme Q10 has helped some colorectal cancer patients live longer. The patients described in these reports, however, also received treatments other than coenzyme Q10, including chemotherapy, radiation therapy, and surgery. No recommended dietary allowance for this nutrient has been set but some leading nutritional specialists are recommending daily levels of 20-30 mg. Consult the advice of a physician.

Vitamin E

Vitamin E is an important antioxidant micronutrient. Research shows that vitamin E not only improves skin health, boosts the immune system, protects against heart disease, aging and Alzheimer’s, but also has a role in protection against some types of cancer, one being colorectal (Kune et al 2006). Vitamin E consists of 8 different compounds, four tocopherols and four tocotrienols. Our food contains all eight compounds. Tocopherols are most commonly found in nuts and vegetable oils, whereas tocotrienols are primarily derived from palm oil, oat, rye, wheat germ, barley and rice bran. Even though the vitamin E family consists of 8 members, most research has traditionally focused on alpha tocopherol; for it is the most abundant form of vitamin E in the plasma and tissue of humans as well as in vitamin supplements, while the 7 other types of vitamin E were greatly ignored for many years. Be aware that all vitamin E supplements are not created equal. Many contain synthetic vitamin E and many do not contain all of the various types of natural vitamin E that the body requires. According to researchers, if supplementing, ensure that both natural tocopherols and tocotrienols in their natural forms are contained. (Kune et al 2006). Dietary sources of vitamin E include green leafy vegetables such as spinach and swiss chard, fortified cereals, vegetable oils, nuts, almonds, olives, papaya, blueberries, and sunflower seeds. The recommended dietary allowance for vitamin E is 15mg for adults, 6-7mg/day for children and 11-15mg/day for adolescents (Strand 2008). As for supplementing with vitamin E (including tocopherols and tocotrienols): 100-400 IU/day for adults (Strand 2008).

Vitamin C

Vitamin C is a water soluble antioxidant that is necessary for normal growth and development. Epidemiological data (data dealing with large populations of patients observed) suggest that a strong association exists between a diet rich in fruits and vegetables high in vitamin C and reduced risk of cancer, especially cancer of the oral cavity, esophagus, stomach, lung and colon (Fontham, 1994, Ferraroni et al, 1994, Levine et al, 1996). All fruits and vegetables contain some amount of vitamin C. Foods that tend to be the highest sources of vitamin C include green peppers, citrus fruits and juices, strawberries, tomatoes, broccoli, turnip greens and other leafy greens, sweet and white potatoes and cantaloupe. Recently, a controlled clinical trial has produced inconclusive results concerning the value of vitamin C supplements in preventing/treating colorectal cancer which generated a great deal of controversy (Heaney et al 2008) from the scientific community. The trial concluded that as little as 100 mg of vitamin C may interfere with the efficacy of chemotherapy and that spurred on the critiques from various parties in support of vitamin C supplementation during cancer therapy (Orthomolecular Health). The recommended dietary allowance for vitamin C is 75mg/day for adult women and 90mg/day for adult men. This amount was selected to provide enough vitamin C to prevent deficiency symptoms (scurvy). Hence, many nutritional specialists are advocating increasing the level to 1000 mg/day. Before doing so, always consult the advice of a physician.


Excess body weight and obesity have been clearly linked to an increased risk of colorectal cancer, making it vital to maintain a healthy weight throughout life to help prevent the disease (Pasche et al 2008, Huxley et al 2007). Obesity is associated with an increased risk of colorectal adenomas (growths or polyps that can become cancerous) but weight loss might reduce the risk (Yamaji et al 2008). Being overweight or obese is thought to have an effect on hormone levels and inflammatory processes in the body which can promote cancer formation. To determine your propensity for excess weight or obesity, an equation called the Body Mass Index (BMI) can be used. BMI is a measure of body fat based on height and weight. Evidence indicates that as BMI increases, colorectal cancer risk increases. Furthermore, those who have a tendency to carry weight around their waistlines are at greater risk of developing the disease. Also a review and evaluation of 7,000 studies on diet, physical activity and weight management and their effect on risk for 17 types of cancer, one being colorectal, the following conclusion was advanced in respect of body weight: “Maintain a normal weight and keep your bmi between 18.5 and 25 in order to avoid developing colorectal cancer as well as other types of cancer” (WCRF).

To calculate BMI:

Weight (lbs) / Height² (inches)x 730 = BMI

A BMI of 18.5 to 25 is considered a healthy weight. A BMI of over 25 is considered overweight. A BMI of over 30 is considered obese.


Studies have shown that those who engage in regular, moderate exercise such as brisk walking, dancing, and skating are at a lower risk of developing colorectal cancer than those who are inactive (Salz et al 2006, Giovannucci et al 2006). Those with higher levels of activity, i.e. more intense/vigorous exercise for a longer duration, can reduce risk even further. Vigorous exercise includes running, cycling, aerobics, and jumping rope. Exercise is thought to lower colorectal cancer risk in part by preventing/reducing excess body weight, another risk factor for colorectal cancer mentioned above, and regulating hormones. The colon acts as a sewage plant. It recycles the materials your body can use and stores the waste for disposal. The longer waste sits in the colon or rectum, the longer toxic materials have to leach out of the solidifying stool and back into your tissues. Exercise gets your body moving, which helps move the waste in your body. This is because exercise stimulates peristalsis, a wave-like muscular contraction that helps push waste through the colon. For adults, it is recommended to get at least 30 minutes of moderate to vigorous activity on three - five days of the week, 45-60 minutes is preferable. If intentional exercise is too difficult to accomplish, simply leading an active lifestyle is far more important. In general, people do not have to go to the gym 3 – 5 times a week for an hour in order to reduce their risk of developing colorectal cancer. People can reduce their risk by increasing physical activity in their daily lives. This can be accomplished by choosing a distant parking space, taking the stairs, shopping, cleaning, going for walks, playing with children or pets, and a multitude of other common activities. Therefore, making an effort to find a fun, physical pastime in the absence of forced intentional exercise is encouraged and can be just as equally rewarding.


Metabolic Syndrome is defined as having a combination of three common chronic medical conditions: hypertension (high blood pressure), diabetes and elevated cholesterol. People with a combination of these common medical conditions have a greatly increased risk of colorectal cancer (Garrow et al 2008). Metabolic syndrome refers to a group of risk factors linked to being overweight and obesity that increase your chance for heart disease, stroke, diabetes and other serious health problems. Having just one of these conditions – increased blood pressure, elevated insulin levels, excess body fat around the waist, or abnormal cholesterol levels – contributes to your risk of serious disease. Researchers suggest that losing weight, eating a healthy diet, and exercising routinely can help to reduce the risk of metabolic syndrome. Also, since individuals with metabolic syndrome have a significantly higher lifetime risk of colorectal cancer, they should closely adhere to published guidelines for colorectal cancer screening (Garrow et al 2008).
Recent research has suggested that the symptoms of metabolic syndrome in affected patients can be reversed with a healthy lifestyle modification program involving low glycemic functional foods, a low glycemic diet and modest exercise. The results of a clinical trial developed by Dr. Ray Strand, (Strand et al, 2005) specialist in nutritional medicine, suggest that after a 12 week lifestyle modification program employed in the study wherein subjects consumed low glycemic meals throughout the 12 week period as well as increased their physical activity to 45 minutes/day, 5 days per week and were provided nutritional supplements , the changes observed were consistent with a reversal of metabolic syndrome and with significant improvements in cardiovascular and metabolic health. Moreover, as the lifestyle program extended, further improvements in health status and reductions in disease risk could be expected, such as a lower risk for colorectal cancer. The graphs below summarize the change in body weight, total cholesterol, serum triglycerides, systolic blood pressure, insulin sensitivity, and urinary 8-isoprostanes (which measures oxidative stress).

People who are at risk for metabolic syndrome or who already are exhibiting signs of the condition are encouraged to engage in regular daily activity and to modify their dietary intake of food (after consulting with their physician) so as to offer a valuable approach for either preventing or reversing a condition that can reduce the risk of developing not only colorectal cancer, but a slew of other degenerative diseases.


Smoking is a notorious risk factor for cancer in organs where there is direct contact with tobacco-related carcinogens, such as lung, oropharynx, larynx and upper digestive tract, but also in organs where exposure to tobacco degradation products is indirect, such as in the colon. Hence, smoking is significantly associated with colorectal cancer incidence (Botteri et al 2008). A wide range of toxic substances produced by tobacco smoke can enter the body through the saliva or blood stream and make their way down to the lining of the bowel where they can damage the cellular DNA and lead to cancer formation. People who have quit smoking are at an elevated risk of developing the disease even many years later compared to those who have never smoked. Risk rises with increasing numbers of cigarettes smoked per day and pack years – the number of packs of cigarettes smoked per day multiplied by years of consumption (Anderson et al 2008). The best advice is to never start smoking, and to quit now if you do, so as to reduce the risk of developing the disease as much as possible.


Regular consumption of alcohol in excess has been shown to increase the risk of developing colorectal cancer (Bongaerts et al 2008). When alcohol is metabolized by the body it produces carcinogens which can accumulate in the bowel and damage cellular DNA. These substances can also inhibit the activity of folate, which at low levels can increase cancer risk, as mentioned above. Alcohol can increase the risk of colorectal cancer regardless of the type of alcoholic drink consumed. Instead, danger seems to come from the alcohol itself rather than other ingredients. Previous studies suggest that while alcohol consumption is associated with an increased incidence of colorectal cancer, data also supported the observation that wine consumption, especially red wine was associated with a reduced incidence of colorectal cancer (Anderson et al 2005). A more recent study didn’t find any relationship between colorectal cancer and types of alcoholic drinks. This means that in general, the risk of developing colorectal cancer would increase whether someone drank two glasses of wine each night or two gin and tonics (Cho et al 2006).

Studies continue to reinforce the idea that to minimize your risk of developing colorectal cancer, it’s best to drink in moderation. Alcoholic beverages should be limited to no more than 2 drinks per day for men and one drink per day for women. A drink is defined as 12 oz. of beer, 5 oz. of wine, and 1.5 oz. of spirits.


The single best way to prevent colorectal cancer is to get screened for the disease and screened regularly. Since colorectal cancer almost always develops from a non-cancerous growth called a polyp, when polyps are detected early they can be removed and the disease can be avoided. In fact, colorectal cancer is over 90 per cent preventable with screening. Screening tests can find polyps or cancers before they are large enough to cause any symptoms. Screening tests are important because early detection means that the disease can be either completely preempted or more effectively treated. Your doctor will choose the tests that are right for you.

The following are a list of screening tests that have been developed for colorectal cancer: • Fecal Occult Blood Test/Fecal Immunochemical Test: This test checks for blood in your stool that you can’t see. Your doctor gives you a test kit and instructions to use at home and then have you return the test to the doctor for testing. If this test is positive, another test is performed with an internal/visual examination of the bowel known as a colonoscopy. (NB: Certain foods and medicines can make this test turn out positive, even though you don’t really have blood in your stool. This is called a “false positive” test. These include some raw vegetables, horseradish, red meat, non-steroidal anti-inflammatory drugs (ie ibuprofen), blood thinners, vitamin C supplements and aspirin. Some medical conditions like hemorrhoids can also cause a false positive test result.)

Barium Enema: For this test, you are given an enema (injection of fluid into the rectum) with a liquid that makes your colon show up on an X-ray. Your doctor looks at the X-ray to find abnormal spots in your entire colon. If you have an abnormal spot or if the radiologist detects polyps in your colon, your doctor will probably want you to have colonoscopy.

Stool DNA Test: This test checks your stool for cells that are shed by colon cancers or precancerous polyps. Your doctor will give you a test kit with instructions on how to collect a stool sample. Your doctor may also ask you to not eat certain foods or take certain medicines that may interfere with test results a few days before the test. If your test turns out positive your doctor will probably want you to have a screening test called colonoscopy.

Colonoscopy: Before you have this test, you are given a medicine to make you relaxed and sleepy. A thin, flexible tube connected to a video camera is put into your rectum, which allows your doctor to look at your entire colon. The tube can also be used to remove polyps and cancers during the exam. Colonoscopy may be uncomfortable, but it is usually not painful.

Virtual Colonoscopy: This is a new test that uses a computerized tomography (TC) machine to take pictures of your colon. Your doctor can then see all of the images combined in a computer to check for polyps or cancer. If your doctor finds polyps or other abnormalities in your colon, you will need to have a traditional colonoscopy to examine them in more detail or to remove them.

Flexible Sigmoidoscopy: In this test, your doctor puts a thin, flexible, hollow tube with a light on the end into your rectum. The tube is connected to a tiny video camera so the doctor can look at the rectum and the lower part of your colon.

HEALTHY EATING AFTER A DIAGNOSIS (treatment or non treatment regimen)

Cancer Diet and Nutrition Getting enough calories to keep up your strength is just one aspect of a colon cancer diet. It is especially important to eat as healthy a diet as possible to:

  • Boost your immune system
  • Deal with possible nutritional deficiencies Cancer Treatment may:
  • Decrease your appetite
  • Lower your ability to digest food
  • Interfere with your body’s ability to absorb and use nutrients Ways to improve colon cancer nutrition during treatment include:
  • Eating many small, nutritious meals
  • Drinking fluids after you eat, not during
  • Eating and drinking fortified foods and shakes when necessary

Supplements Many people take vitamin and mineral supplements. But antioxidants such as vitamins C and E can interfere with chemotherapy’s ability to kill cancer cells. A dietitian can determine how to balance cancer and nutrition, and tell you what supplements are good to take.

The following points extracted from: “Complementary Medications and Chemotherapy” a book by Sharya Vaughn Bourdet, PharmD and Robert Ignoffo, PharmD, Clinical Professor UCSF.

Vitamins and Antioxidents

The use of complementary and alternative medicine for the prevention and treatment of various diseases has become more popular in recent years than ever before. With the growth of the Internet, consumers now have more accessibility to information and advertising about alternative products. Some people are reluctant to take prescription medications because of fear of unwanted effects. Thus, they turn to dietary and herbal supplements to treat their illnesses because they feel these products are natural and safe. Some individuals may also choose to take both traditional and alternative medicine to treat illnesses, which is especially common in those receiving treatment for cancer. Surveys indicate that 7% to 64% of cancer patients use alternative medicine. However, as many as 50% do not tell their physician that they take alternative therapies.

Several types of alternative therapies exist, including herbals, vitamins, and dietary products. Many of the benefits from these products result from their antioxidant properties. Antioxidants have received much media attention in recent years regarding cancer prevention. A diet rich in fruits and vegetables, which are good sources of antioxidants, has been reported to lower a person’s risk for some types of cancer. Antioxidant supplements, which contain larger amounts of antioxidants than contained in food sources, have also been reported to decrease a person’s risk of developing certain types of cancer. Specifically, vitamin E and selenium supplements have been shown to reduce the incidence of prostate and colon cancer.

Antioxidants are also used by some patients during cancer treatment in the hopes of reducing the side effects of chemotherapy. Two prescription antioxidants, Mesnex® (mesna) and Ethyol® (amifostine), are available which specifically prevent certain side effects of cancer agents such as ifosfamide, cyclophosphamide, and cisplatin. Since these two antioxidants are for prescription use only, they have been evaluated in human studies by the Food and Drug Administration (FDA) and found to not reduce the effectiveness of cisplatin, cyclophosphamide, or ifosfamide in the treatment of cancer. Non-prescription antioxidant supplements are considered to be dietary products and are not regulated by the PDA. Human studies showing the impact of dietary supplements on chemotherapy effectiveness are not required for these products to be sold in the United States.

There are many different chemotherapeutic agents used to treat cancer. Most of the agents can be grouped into classes based on how they work against cancer cells. Several classes of chemotherapy work by producing a reactive oxygen compound or free radical. Free radicals can damage proteins or other structures within cells which leads to the death of the cell or an inability to divide and make new cells. Table (1) shows the common chemotherapy agents that work by producing free radicals. While cancer cells are the main target of chemotherapy, normal cells may be affected as well, causing side effects such as hair loss, low blood cell counts, and mouth sores.

There are many different chemotherapeutic agents used to treat cancer. Most of the agents can be grouped into classes based on how they work against cancer cells. Several classes of chemotherapy work by producing a reactive oxygen compound or free radical. Free radicals can damage proteins or other structures within cells which leads to the death of the cell or an inability to divide and make new cells. Table (1) shows the common chemotherapy agents that work by producing free radicals. While cancer cells are the main target of chemotherapy, normal cells may be affected as well, causing side effects such as hair loss, low blood cell counts, and mouth sores.

Table 1: Chemotherapeutic Agents Producing Free Radicals

  • Alkylating agents cisplatin (Platinol®) carboplatin (Paraplatin®) chlorambucil (Leukeran®) carmustine (BiCNU®) cyclophosphamide (Cytoxan®) busulfan (Myleran®) ifosfamide (Ifex®)
  • Anthracyclines doxorubicin (Adriamycin®, Doxil®) daunorubicin (Cerubidine®) epirubicin (Ellence®) Mitomycin (Mutamycin®) BIeomycin (Bleoxane®)
  • Podophyllum agents etoposide(VP-I6, Vepesid®) teniposide (Vumon®)

Antioxidants are compounds that bind and inactivate free radicals. Free radicals are normally produced from many of the body’s everyday stresses such as inflammation, exercise, alcohol, ultraviolet light, and fatty diets. A healthy diet complete with fresh fruits and vegetables provides enough dietary antioxidants to inactivate the normal production of free radicals. Antioxidant supplements, which contain mega-doses of antioxidants, are available in many health-food stores and pharmacies. Table (2) lists some common antioxidants that may be found in dietary supplements. Antioxidants may decrease chemotherapy-induced damage of normal cells by inactivating free radicals, but the same damage may also be decreased in cancer cells. Therefore, doses of antioxidants that are larger than that provided in a normal diet may potentially interfere with the effectiveness of certain chemotherapy agents by reducing their action in cancer cells.

Table 2: Common Antioxidants Found in Dietary Supplements

  • alpha lipoic acid
  • grape seed extract
  • (proanthocyanidins)
  • beta-carotene
  • lutein
  • vitamin A
  • lycopene
  • vitamin C (ascorbic acid)
  • selenium
  • vitamin E (alpha-tocopherol)
  • zinc
  • coenzyme (CoQlO)

The combination of antioxidants and chemotherapeutic agents may present some potential problems to the patient and health care provider. First, many patients do not tell their physician they are taking antioxidants because they fear disapproval from the physician or have never been asked about such therapies. Second, the use ofantioxidant supplements during chemotherapy has not been studied to assess long-term effects such as safety or survival. Since no such scientific studies have been conducted, the potential interactions between antioxidants and chemotherapy must be predicted from currently available knowledge.

Patients should fully understand the possible consequences of combining antioxidant supplements and chemotherapy. Based on the current knowledge available, there is a potential reduced effectiveness of certain chemotherapeutic agents when combined with antioxidants. This means that patients may not receive the full benefit of cancer treatment. Whether a reduced benefit corresponds to therapy failure such as a lack of clinical response, continued progression of the cancer despite therapy, or decreased long-term survival has not yet been determined. Patients and physicians should be aware that combining antioxidants with chemotherapy may improve side effects in the short-term but may hinder long-term survival or clinical response. Patients and physicians should decide on a course of action that ensures maximum clinical benefit yet embraces the patient’s wishes regarding therapy. This plan may include the decision not to take antioxidants and chemotherapy at the same time, to find chemotherapeutic agents that have no possible interaction with antioxidants, or not to take antioxidants at all during cancer treatment.

It is important that patients and health care providers be informed about all possible interactions between dietary supplements and medications. This means that health care providers should ask patients about the use of alternative therapies and that patients should be open and honest with providers when asked. Patients and physicians should jointly decide a plan of action for using alternative therapies that will achieve the goals of both the physician and patient. New information concerning alternative therapies is continually becoming available. Possible interactions between therapies such as antioxidants and chemotherapy should be re-evaluated once more information is available and long-term clinical studies have been conducted.

In the meantime, the following are specific recommendations for those cancer patients who are taking antioxidant supplements or herbal medications. taking antioxidant supplements or herbal medications.

1. Inform your doctor(s) that you are currently taking dietary or herbal products. In order for your doctor to keep an accurate list of medications, it may help to bring the products or a list of ingredients and doses with you at your office visits. 2. Keep your doctors) updated if you start any new dietary or herbal products. 3. As a general rule, discontinue taking antioxidants the day before, during, and the day after receiving chemotherapy. 4. Antioxidants are available in many forms including vitamin, mineral, and herbal supplements. If you are not sure if a dietary supplement that you are taking contains an antioxidant, ask your doctor or pharmacist.

For further questions about the use of dietary supplements, you may wish to consult the following references.

1. Labriola D, Livingston, R. Possible Interactions Between Dietary Antioxidants and Chemotherapy, Oncology 13(7); 1003-7,1999. 2. (Sponsored by the National Cancer Institute) 3. http://nccam.nih-gov (Sponsored by the National Center for Complementary and Alternative Medicine) 4. (Sponsored by the American Cancer Society)

Herbal Medications

The use of herbal medications is a common occurrence in patients being treated for cancer. They are touted for their medicinal properties and may be useful for treating some of the side effects associated with chemotherapy. However, being derived from botanicals, some herbal products may have impurities (bacteria, fungi, or parasites) that could put patients at risk for infections during the period of decreased white blood counts. In addition, some herbal preparations have adverse effects of their own that may worsen toxicities from high dose chemotherapy (see list below). These are absolutely contraindicated because of these serious side effects. Thus, many institutions advise patients to discontinue herbal and nutrient supplements before and during chemotherapy because of these risks.

There are claims by Chinese herbalists that many of their preparations may be helpful in minimizing side effects of chemotherapy. They may work through the same antioxidant mechanisms described for the vitamin preparations. Further study is necessary to determine if they may affect the efficacy of some chemotherapy regimens. In addition many studies are underway in the United States to determine whether traditional Chinese herbal medications are beneficial in improving patient quality of life while receiving chemotherapy.

From Cassileth: Cancer Nursing 22:85-90, 1999

References on Herbal Medications:

1. Cassileth B. Complementary Therapies: Overview and state of the Art. Cancer Nursing22:85-90,1999 2. The Complete German Commission E Monographs. Therapuetic Guide to Herbal Medications. M. Blumenthal,ed. American Botanical Council, Boston Mass, 1998 3. Tyler Varro: Herbs of Choice. Therapeutic Use of Phytochemicals. 4. Tyler’s Honest Herbal: A Sensible Guide to the Use of Herbs and Related Remedies by Steven Foster and Varro E. Tyler

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A colon cancer diet many patients tolerate well includes:

  • Whole grains
  • Fresh, raw vegetables and fruits
  • Legumes such as beans and lentils
  • Non fatty fish, chicken and meats, free of hormones and additives

These foods supply your body with:

  • Complex carbohydrates
  • Vitamins, minerals and enzymes
  • Easily digestible protein

Vegetables with cancer preventive compounds include:

  • Broccoli
  • Cabbage
  • Cauliflower
  • Kale
  • Winter squash

Fats and protein are important in a colon cancer diet:

  • Good fats are very important. These include olive oil and omega-3 oils including flax seed oil and fish oil.
  • Avoid processed fats and oils, such as trans and hydrogenated fats in margarines and fats used for baking.
  • Your body may be better able to tolerate fish and chicken and less able to digest red meat.
  • If you do eat meat, try to buy grass-fed or free-range. Stay away from highly processed meats, especially those that include nitrites and nitrates.


  • Eat a variety of foods. The more variety in your diet, the less chance there is of attracting diseases.
  • Whole natural foods naturally contain substances to protect you against illnesses.
  • Limit your overall fat consumption, favouring good fats. Described above. It is better to steam, boil, bake or stir-fry food.
  • Eat more fruits and vegetables. If you can, choose fresh organic fruits and vegetables as they have higher nutrient values. Eat garlic if you can tolerate it.
  • Eat more high fibre foods such as whole grain breads, cereals and legumes.
  • Eliminate refined sugars, junk food and empty processed food.
  • A good colon cancer diet is similar to a colon cancer prevention diet. The main differences are that people undergoing chemotherapy may have higher nutritional needs and poor appetites. It is very important to eat the most nutritious foods you can get.

Cancers are very opportunistic. They attack when your immune system is weak. Your goal is to strengthen your immune system and create a healthy body where cancer cells have difficulty growing. Fortunately most cancers respond well to dietary improvements.


Some people have risk factors that make them more likely to develop colorectal cancer at a young age. Screening should begin earlier in these people. Screening for colorectal cancer should begin at a younger age if:

  • You have had colorectal cancer or polyps in the past.
  • You have a family history of colorectal cancer or polyps.
  • You have ulcerative colitis or Crohn’s disease.
  • You have a hereditary colon cancer syndrome.
  • You eat a high fat, low fibre diet.

Those at a higher risk of developing the disease, i.e. those with a family history, should speak to their doctors about special screening guidelines.

LINKS Canada Food Guide (

National Institute of Health’s Office of Dietary Supplements (

Dr. Ray Strand, Specialist in Nutritional Medicine (

Canada’s Physical Activity Guide (

World Cancer Research Fund, Food, Nutrition, Physical Activity and the Prevention of Cancer: A Global Perspective (

Health Canada’s Guide to Becoming a Non-Smoker (

Colorectal Cancer Association of Canada’s Guide to Screening (

NCI Cancer Information (

Fruits and Vegetables Matter

The Colorectal Cancer Association of Canada recommends all Canadians aged 50 and over get screened. Some people have risk factors that make them more likely to develop colorectal cancer at a young age. Screening should begin earlier in these people. Screening for colorectal cancer should begin at a younger age if:

•You have had colorectal cancer or polyps in the past
•You have a family history of colorectal cancer or polyps
•You have ulcerative colitis or Crohn’s disease
•You have a hereditary colon cancer syndrome
•You eat a high fat, low fiber diet

Those at a higher risk of developing the disease, i.e. those with a family history, should speak to their doctors about special screening guidelines.


Canada Food Guide 

National Institute of Health’s Office of Dietary Supplements

Dr. Ray Strand, Specialist in Nutritional Medicine

Canada’s Physical Activity Guide 

World Cancer Research Fund, Food, Nutrition, Physical Activity and the Prevention of Cancer: A Global Perspective

Health Canada’s Guide to Becoming a Non-Smoker 

Colorectal Cancer Association of Canada’s Guide to Screening

NCI Cancer Information