The large intestine is about 5ft long, and it is followed by a 5.5-inch rectum ending with the anus.
While there is a strong link between people possessing the gene TGFBR1 and colon cancer, those suffering from diabetes or are pre-diabetics are also at risk.
Many people with colon cancer experience no symptoms at all until the cancer is in its advanced stage.
Bloody stool is its most common symptom. As the tumours grow, they can bleed during the passage of faeces through the colon. It is common for blood to be hidden in the stool unless bleeding is near the rectum. So detection is not always easy.
If the tumour grows large enough to block the passageway of the large intestine, swelling and pain of the abdomen can occur.
Patients may suffer unexpected weight loss caused by loss of appetite. Constipation, diarrhoea or painful bowel movements may also happen.
Causes of colon cancer include genetic predisposition and dietary/lifestyle habits. Regular cigarette smoking promotes the development and growth of polyps in the colon, especially those that are more likely to progress into colon cancer.
Although more sophisticated diagnostic methods are available, colonoscopy and blood markers are the most common tests used in preventive medicine.
Removing polyps in the colon and rectum through colonoscopic polypectomy can result in a lower incidence of colorectal cancer.
According to US National Institute of Cancer, up to 40% of cancer patients die not from their cancers but from malnutrition resulting from this systemic metabolic disorder.
► Red or processed meat
Intake of these food sources are positively linked to increased colorectal cancer risk although red meat appears to be more strongly linked to rectal cancer.
Cellular mutagens can come from deep-fried, grilled food, food preservatives and pesticide residuals found in our food chain. Even fluoride and chlorine added to drinking water have been found to be carcinogenic. It may be safer to drink filtered ionised alkaline water at a pH appropriate for you.
► Whole grains
High consumption of whole grains is associated with a lower risk of colon cancer, but, unfortunately, not rectal cancer. On the other hand, refined starches such as white rice, noodles, buns, bread, cornflakes, instant oat, and sugar are likely to have the opposite effect.
Fish containing omega-3 fats with EPA/DHA can prevent development of colorectal cancer and chronic inflammation. Omega-3 monounsaturated fats may also be found in flax seed oil and in some nuts, and beans.
► Vegetables & spices
While vegetable oils (corn, sunflower) are easily oxidised to form carcinogenic free radicals, virgin coconut oil is rather stable even when used in frying.
Nutrients in turmeric and onions reduce both the size and number of pre-cancerous lesions and polyps in the human intestinal tract. Indeed, turmeric is able to stop or slow cancer growth in all its three growth stages, from initiation to progression.
Aged garlic may reduce risk of colon cancer. Cruciferous vegetables that have been shown to promote cancer cell apoptosis by the express-ion of p53 gene.
People who eat a diet high in fibre (10g daily of total dietary fibre) have a reduced risk of developing colorectal cancer.
Milk and its products are linked to higher risk of colorectal cancer. Children who consume high amounts of dairy products may have a greater risk of developing colon cancer during adulthood.
► Berries & nuts
Berries (not fruits) can inhibit the growth of colon cancer cells. Of 36 flavonoids tested, myricetin was found to be the most potent inhibitor of MMP-2 enzyme responsible for colon cancer metastasis (spread).
Rich sources of this phytonutrient include blueberries (2.66mg per 100g), blackberries (0.67mg per 100g), cranberries (6.78mg per 100g) and red onions (2.7mg per 100g).
Raw organic walnut is a good source of this nutrient too.
Consumption of soy foods may reduce the risk of colorectal cancer in post-menopausal women. Extensive studies confirm the merits in replacing animal with soy protein in the adjunct treatment of most cancer.
Views expressed are those of the author, who’s president of the Federation of Complementary & Natural Medical Associations, and not necessarily those of the professional bodies and government committees of which he’s a member. Dato’ Steve Yap can be contacted at email@example.com.