Bowel Cancer and Diet

POSTED BY sian | Jan, 26, 2018 |

Bowel cancer is a malignant tumour of the large bowel (colon) or back passage (rectum). Bowel cancer is the 4th most common cancer in the UK with over 41,000 new cases diagnosed each year1. Bowel cancer is most common in the over 60’s and is rare in people younger than 40 years old. Survival is best if the cancer is discovered early with a 93% survival for early cancer but if the cancer has spread to other parts of the body few people survive 5 years2. The majority of cases develop from polyps (tiny growths in the bowel), which if left untreated can develop into cancer.

The symptoms of bowel cancer are variable and can include:

  • Diarrhoea or loose poo for over 3 weeks
  • Blood in the poo
  • Losing weight
  • Some cancers can bleed and cause anaemia which may lead to tiredness and breathlessness

If you are suffering from any of these symptoms it is very important you see a bowel specialist for investigation

Diet and bowel cancer risk

The biggest single risk factor is age. More than 8 out of 10 bowel cancers are diagnosed in people aged 60 or over. The chance of getting bowel cancer also goes up if there is bowel cancer in your family.

There are some medical conditions that increase the risk of bowel cancer and these include; Ulcerative Colitis, Crohns Disease and Diabetes.

However, there is strong evidence from the World Cancer Research Fund (September 2017) that:

  • being physically active decreases the risk of colon cancer
  • consuming wholegrains decreases the risk of colorectal cancer
  • consuming foods containing dietary fibre decreases the risk of colorectal cancer
  • consuming dairy products decreases the risk of colorectal cancer
  • taking calcium supplements decreases the risk of colorectal cancer
  • consuming red meat increases the risk of colorectal cancer
  • consuming processed meat such as bacon, ham, salami, increases the risk of colorectal cancer
  • consuming approximately two or more alcoholic drinks per day increases the risk of colorectal cancer
  • being overweight or obese increases the risk of colorectal cancer

Please see a Registered Dietitian for further detailed guidance on your longer-term goals for your diet if you are recovering from bowel cancer.

Diet and Bowel cancer treatment

The best treatment for bowel cancer is an operation to remove the cancer. Nowadays, these operations are performed by keyhole surgery and patients typically spend less than a week in hospital.

Often, surgery is all the treatment that is needed but if the cancer is more advanced, chemotherapy is recommended and can last for 6 months. Surgery can also be used to remove certain cancers that have spread to the liver or lungs but this is not always possible.

After surgery you will find that your digestion takes time to settle down. The most common problems are loose stools, diarrhoea and wanting to go to the toilet more frequently with a greater feeling of urgency.

Diet is very important in ensuring you recover well from surgery incorporating a high protein/high energy diet and addressing dietary issues if they arise. Please see our blog Diet following Bowel Cancer surgery.

If more information is required, do arrange an appointment with a Registered Dietitian.

If radiotherapy or chemotherapy is required, this can sometimes make you feel sick, reduce your appetite and sometimes weight loss, altered taste or bowel changes. A Registered Dietitian can provide dietary guidance during this time to help you manage these symptoms.

Helpful resources

  1. Be.macmillan: Booklets and fact sheets
  2. World Cancer Research Fund: Resources on diet
  3. Cancer Research UK: Including cancer food myths


  1. Cancer Research UK: Bowel cancer statistics
  2. Cancer Research UK: Statistics and outlook for bowel cancer


This blog was written by:

Mr Lee Dvorkin MD FRCS (Gen Surg), Consultant General & Colorectal Surgeon
Mrs Sian Shepherd, Registered Specialist Gastroenterology Dietitian


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