April is Bowel Cancer Awareness month, and we felt that this was a great opportunity to discuss bowel cancer- how to recognise the symptoms, to highlight the importance of bowel cancer screening and importantly to highlight all the simple things that you can do to reduce your risk of developing bowel cancer.
Bowel cancer is common – according to theIrish Cancer Society more than 2,800 people are diagnosed with it each year. In the UK nearly 43,000 people are diagnosed with bowel cancer every year – Bowel Cancer UK . It is the third most common in both women and men; after lung and breast cancer in women, and lung and prostate cancer in men. It is a little more common in men than women.
Caught early, bowel cancer is very treatable.
What is bowel cancer?
Bowel cancer is also known as colorectal cancer and can occur in any part of the large bowel (colon) or rectum. It is caused by uncontrolled growth of a group of cells in the lining of the bowel. Most cancers develop slowly over time from benign precursor lesions called polyps. Polyps can change and grow slowly and eventually undergo cancerous change. Polyps can be removed from the bowel during a colonoscopy, and in this way prevent the development of cancer
What are the risk factors for bowel cancer?
- Aged 50+: bowel cancer most commonly develops in older people, but there has been a rise in so-called early-onset colorectal cancer in many parts of the developed world.
- Family history of bowel cancer – particularly if a first degree relative has had bowel cancer; a number of second degree relatives on one side of your family. There are certain ‘syndromes’ where people have inherited a particular genetic mutation, which predisposes them to the development of bowel cancer. These include Lynch Syndrome (also known as HNPCC or Hereditary non-polyposis colorectal cancer) or Familial Adenomatous Polyposis (FAP).
- History of other bowel conditions e.g. Crohn’s, ulcerative colitis or benign polyps
- Smoking, alcohol, poor diet and sedentary lifestyle are all risks
What are the red-flag symptoms?
- Bleeding from your back passage and/or blood in your stool
- Persistent and unexplained change in bowel habit
- Unexplained weight loss
- Pain or lump in your tummy
- Unexplained anaemia
- Feeling as if you haven’t emptied your bowel fully after going to the toilet
What About Bowel Cancer Screening?
The aim of all colon cancer screening programmes is to detect pre-cancerous polyps (which can be removed at the time of colonoscopy, and therefore prevent the development of bowel cancer) or to detect a cancer at an early stage (earlier than it would otherwise have come to light), so that treatment can be curative.
In Ireland, BowelScreen, the National Bowel Screening Programme, offers free screening to women and men aged 60 to 69 every two years. It is a simple at home test known as a Faecal Immunochemical Test (FIT), which tests for hidden blood in your stool. You simply collect a sample of your stool and send it off to be checked. If you have abnormal results you will be invited for a colonoscopy. It’s important to note that blood in your stool is not necessarily a sign of bowel cancer, nor does a negative result mean you will not develop bowel cancer in the future. No screening test is 100% accurate.
See Bowel Screen for more information
Similar screening programmes operate in the UK but the age ranges vary between England, Scotland, Wales and Northern Ireland. Bowel Cancer UK has some excellent information on each of the different screening programmes. In the US, most adults will commence screening for bowel cancer via colonoscopy at 50 years of age.
Reducing your Bowel Cancer Risk
Numerous studies from around the world have identified certain dietary and lifestyle factors that can either increase or reduce your risk of developing bowel cancer. You can’t change your age or your genetics, but there are lots of things that you can do in terms of diet and lifestyle, which will reduce your risk of bowel cancer. And the good news is that these things will also reduce your risk of other cancers and health conditions such as heart disease, high blood pressure, overweight and type 2 diabetes.
Things that reduce the risk of bowel cancer:
- Fibre: eating vegetables, fruit and wholegrains, ideally aiming to have a daily fibre intake of 20-35g / day (and more if you can tolerate it)
- Calcium and dairy products: Diets high in calcium (which includes dairy products) have been shown to reduce the risk of bowel cancer, as calcium has an inhibitory effect on cancer cell growth
- Vitamin D: although the results are not definitive, there is some evidence to suggest that adequate vitamin D levels also reduce the risk of developing bowel cancer. Yet another reason to take vitamin D
- Regular exercise: physically inactive people have a 50% higher risk of developing bowel cancer than active people.
- Limit alcohol intake: it has been estimated that drinking 2-3 units of alcohol per day increases the risk of bowel cancer by 20%, and drinking 4 or more drinks per day increases the risk by 50%.
Factors known to increase the risk of bowel cancer are:
- Diet high in red meat, processed meats and saturated fat: Processed meats are meats that have been cured in some way to increase shelf life- these include bacon and most ‘deli’ meats. It has been estimated that 50g of processed meat per day increases the risk of bowel cancer by 17% and 100g of red meat per day increases the risk by 18%. Cooking meat at very high temperatures so that the outside is blackened (frying or barbecuing for examples) is also associated with an increased risk, and the darkened surface of the meat has been shown to contain some carcinogenic (cancer-inducing) substances
- Obesity and overweight: Overweight men and women have an increased risk of 50% and 20% respectively, of developing bowel cancer. There are many and complex mechanisms involved in this. It has been estimated that the lifetime risk of bowel cancer increases by 3% for every 5kg of weight gain.
- Alcohol excess: see above
- Smoking: Smoking increases the risk of all cancers, and this includes bowel cancer. Smokers have a 2-3 fold increased risk of developing bowel cancer
- Lack of exercise: see above
- Lack of fibre in the diet: see above
- Diets low in calcium, vitamin D and dairy products: An analysis by the World Cancer Research Fund and The American Institute for Cancer Research in 2018 concluded that the evidence supported a reduced risk of bowel cancer in people who had high consumption of dairy products (in particular milk).
- High fructose corn syrup: this is widely used in North America as an artificial sweetener, and increased use of HFCS has been associated with the increase in early-onset bowel cancer that is being seen in parts of the developed world.
So is red meat off the table?
No, red meat isn’t off the table but you should limit the amount of it that you eat. Red meat is a great source of protein, iron, zinc and vitamin B12. Breakthrough Cancer Research recommends eating no more than about three portions per week. This is equivalent to about 350 – 500 g cooked weight of red meat spread across the week.
Processed meats are best eaten in small amounts.
The Gut Experts Tips to reduce your risk of Bowel Cancer
- Eat a Mediterranean style diet- this ticks all the boxes
- Choose fish instead – it’s delicious, nutritious and makes a great alternative to red meat. Don’t be intimidated by fish, it often needs little done to it.
- Eat more white meat i.e. chicken, turkey
- Eat smaller portions of red meat and have a number of meat free days each week
- Cook red meats at lower temperatures e.g. stewing rather than grilling or frying.
- Aim for 20-35g of fibre per day; eat plenty of whole grains, colourful fruit and vegetables. Remember to eat the rainbow.
- Don’t smoke
- Keep alcohol to a minimum
- Take a vitamin D supplement
- Don’t cut out dairy foods unnecessarily – they have many benefits and this is just one of them.
- Try to exercise regularly: 4-5 times per week. It doesn’t have to be a killer work-out in the gym, walking is an excellent form of exercise for gut health
©The Gut Experts 2022
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