Colonoscopy Q&As
Published by Bupa's health information team, February 2009.
Answers to questions about colonoscopy
This section contains answers to common questions about this topic. Questions have been suggested by health professionals, website feedback and requests via email.
- What kind of food and drinks are allowed before a colonoscopy?
- I have been told to stop taking iron tablets before my colonoscopy - why is this?
- What happens if I need treatment after the colonoscopy?
What kind of food and drinks are allowed before a colonoscopy?
Your doctor will usually ask you to stop eating solid food one day before your colonoscopy and only drink clear liquids on the day before, and the day of, your test.
Explanation
A colonoscopy is a test that allows your doctor to look inside your large bowel. So that your doctor can see the inside of your bowel easily, it needs to be completely empty. To do this you may be asked to change your diet before the procedure.
Your doctor will ask you not to not eat any high-fibre foods for two to three days before your colonoscopy. High-fibre foods include fruit and vegetables, red meat or pink fish, wholemeal bread, rice, pulses or nuts. Low-fibre foods include boiled or steamed white fish, eggs, boiled chicken, cheese, white bread, boiled potatoes without skins, or plain biscuits (for example 'rich tea').
You will need to drink plenty of fluids so that you don't become dehydrated, but not milk or fluids containing milk.
Your doctor might ask you to stop eating solid foods and only drink clear fluids one day before your colonoscopy. Clear fluids include water, squash, clear soup, meat extract drinks, strained fruit juice, lemonade, jelly (not containing fruit) and tea and coffee (without milk).
On the day of your colonoscopy you're usually allowed to drink clear fluids up three to four hours before your procedure.
Your hospital will provide you with detailed fasting instructions before your colonoscopy appointment, which you will need to follow carefully.
Further information
- NHS Bowel Cancer Screening Programme
0114 271 1060
www.cancerscreening.nhs.uk
Sources
- Bowel cancer screening - the colonoscopy investigation. NHS Cancer Screening Programmes, 2006. www.cancerscreening.nhs.uk
- Personal communication, Mr S Pollard, Consultant General Surgeon, Spire Leeds Hospital, 19 July 2008
I have been told to stop taking iron tablets before my colonoscopy - why is this?
A colonoscopy is a test that allows your doctor to look inside your large bowel. Iron coats the lining of the bowel making it difficult for your doctor to see the bowel wall.
Explanation
Iron tablets are taken to treat anaemia. Anaemia is a condition where you have too few red blood cells or not enough haemoglobin in your blood. The most common type of anaemia is caused when there isn't enough iron in the body. This is known as iron-deficiency anaemia. The aim of a course of tablets is to make up for the shortage of iron and to build up your body's stores of iron to the normal level.
Your doctor will usually advise you to stop taking iron tablets or vitamin supplements that contain iron, seven to 10 days before your colonoscopy. The iron in the tablets is black, sticks to the bowel wall and can cause constipation. This isn't harmful but can make it difficult for your doctor see the bowel wall clearly. Stopping iron tablets for seven to 10 days before your colonoscopy allows the effect of the iron on the bowel to wear off, allowing your doctor to see the bowel wall clearly.
In place of your iron tablets, you could make sure that your diet contains foods high in iron, for example, dark green leafy vegetables such as watercress, iron-fortified cereals, meat, beans, nuts, apricots, prunes and raisins. You could take sachets of organic iron instead, but stopping iron supplements completely for this short period doesn't usually have any harmful effects.
You may begin taking your iron supplements again immediately after your colonoscopy.
Sources
- Examining the bowel. Cancer Research UK. www.cancerhelp.org.uk, accessed 15 May 2008
- Iron. Food Standards Agency. www.eatwell.gov.uk, accessed 10 July 2008
- Personal communication, Mr S Pollard, Consultant General Surgeon, Spire Leeds Hospital, 19 July 2008
What happens if I need treatment after the colonoscopy?
If you have had polyps removed during your colonoscopy, you will need to have a follow-up assessment in one or three years' time, depending on the number and size of the polyps that were removed and whether you have had polyps before. This is because if you have developed polyps, you may continue to get new ones. You will usually have another colonoscopy. If the colonoscopy shows that you have a cancer of the bowel, you will need treatment. The main types of treatment for bowel cancer are surgery, chemotherapy and radiotherapy and often a combination of these is used.
Explanation
If you have polyps removed during the colonoscopy, your doctor will tell you if you're in a low, medium or high-risk group for future polyps developing into cancer. This depends on the number and size of the polyps you have had removed. If you're in a low-risk group, your doctor may ask you to have a colonoscopy in five years' time. If you're in the medium- or high-risk group, your doctor will ask you to have another colonoscopy in one or three years' time, depending on the nature of your polyps.
If the colonoscopy shows a cancer, you will need to have more tests to find out exactly how advanced the cancer is and whether it has spread. The main treatment for bowel cancer is surgery, the aim of which is to remove the cancer completely. Chemotherapy uses medicines and radiotherapy uses radiation to destroy cancer cells. These are given before and/or after surgery to reduce the size of the tumour and to reduce the risk of the cancer coming back.
Radiotherapy is a treatment to destroy cancer cells with radiation. It's usually used for rectal cancer and can be used before or after surgery.
Your doctor will discuss with you which is the best treatment for you.
Further information
- NHS Bowel Cancer Screening Programme
0114 271 1060
www.cancerscreening.nhs.uk
Sources
- NHS Bowel Screening Programme. NHS Cancer Screening Programmes. www.cancerscreening.nhs.uk, accessed 5 June 2008
- Bowel cancer screening - the colonoscopy investigation. NHS Cancer Screening Programmes, 2006. www.cancerscreening.nhs.uk
- Atkin WS, Saunders BP. Surveillance guidelines after removal of colorectal adenomatous polyps. Gut 2002; 51:v6-v9. http://gut.bmj.com
Related topics
This information was published by Bupa's health information team and is based on reputable sources of medical evidence. It has been peer reviewed by Bupa doctors. The content is intended for general information only and does not replace the need for personal advice from a qualified health professional.
Publication date: February 2009
Colonoscopy factsheet
Visit the colonoscopy health factsheet for more information.
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