The relationship between Colon Cancer and Diet

July 22, 20180

Colon cancer is one of the most common cancers in Germany. Around 61,000 people were diagnosed with colon cancer in 2014 and it increases every year. The main symptoms of colon cancer include:

  • A persistent change in bowel habit, causing you to go to the toilet, more often and pass looser stools
  • Abdominal pain, discomfort or bloating
  • Weight-loss
  • Blood on or in your stools, or bleeding from the back passage
  • A straining feeling in the rectum
  • A lump in your back passage or abdomen
  • Tiredness caused by anaemia

The risk of colon cancer increases with ageing. 80% of people are diagnosed and develop colon cancer at the age of 70 and only around 10% of colon cancers are diagnosed before the age of 55. World Cancer Research Foundation (2009) estimate that 11-12% of colon cancer is due to low consumption of dietary fibre. Other risk factors include:

  • Ageing
  • Personal history of colorectal cancer or polyps
  • Inflammatory intestinal conditions
  • Family history of colon cancer and colon polyps
  • Obesity
  • Diabetes
  • Smoking
  • Sedentary lifestyle
  • Dietary factors


What is a protective diet?

Increased dietary fibre intake has been associated with lower risk of colon cancer, as well as it helps to maintain a healthy weight and lower the risk of diabetes and heart disease. Fibre can be found mainly in fruits, vegetables, whole grains and legumes. Recommended daily intake of fibre for 50 years old and younger women is 25 grams and for men 38 grams. For 51 years old and older women is 21 grams and for men 30 grams per day.

Dietary fibre includes the parts of plant foods our body can’t digest or absorb, therefore it passes through our stomach, small intestine, colon and out of our body instantly. There are two types of fibre, soluble and insoluble. Soluble fibre dissolves in water and forms a gel-like material which could lower blood cholesterol and glucose levels. This type of fibre is found in oats, peas, beans, apples, citrus fruits or carrots. Insoluble fibre promotes the movement of material through our digestive system and increases stool bulk. Good sources of insoluble fibre are nuts, beans, vegetables or whole-wheat flour.

A diet high in fibre has many benefits such as:

  • Normalizes bowel movements
  • Helps maintain bowel health
  • Lowers cholesterol levels
  • Helps control blood sugar levels
  • Helps with achieving healthy weight


What diet increases the risk of colon cancer?

Diet which increases the risk of colon cancer includes the consumption of red and processed meat. It is associated with increased incident of carcinogenesis in the colon. When meat is hit by high temperatures the components of meat on the surface area could be converted to carcinogens. In addition, red meat contains more haem iron which is associated with colorectal tumour growth. Colon cancer risk is 20-30% higher per 100-120g/day of red meat intake and 40-50% higher per 30-40g/day of processed meat intake.


What does research suggest?

A prospective study examined the association between dietary fibre intake and the incidence of colorectal cancer in 521.000 participants aged 24-70 years. After a follow-up study it has been shown that total dietary fibre consumption was positively associated with colorectal cancer risk (Bingham et al., 2003). There results are supported by another study done on Swedish women where total fruit and vegetable consumption showed reduced risk of colon cancer, however the strongest association was seen in the group with the lowest consumption of fruit and vegetable. Therefore, we can conclude that the increased intake of fruit and vegetable is the most beneficial for people who consume less than 2 servings of fruit and vegetable per day (Terry et al., 2001).

Cancer is an inflammatory disease; therefore, it has been suggested that increased intake of fresh, canned or smoked fish could reduce the risk by 30%. The mechanisms are associated with increased intake of omega 3 fatty acids which are a protective element in the diet (Norat et al., 2005).

High consumption of red and processed meat increased the risk by 55% when the consumption of red and processed meat increased by 100g/day. This results are supported by a prospective study among 88.000 women without a history of cancer. After a 6 year follow-up there were 150 cases of colon cancer which supports the hypothesis that a high intake of animal fat increases the risk (Wittet et al., 1990).



There is an evidence based on existing literature that red and processed meat increases the risk of developing colon cancer. Fish, fruit, vegetable and dietary fibre are an important part of the diet as they have a protective effect.

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