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Protecting against bowel cancer

Men and women discussing bowel cancer

This page tells you about other ways to reduce your risk of bowel cancer, apart from with a healthy diet. You can find the following information

 

A quick guide to what's on this page

Exercise

People who do more physical exercise have a lower risk of large bowel (colon) cancer. We don't know why exercise helps. It may affect your hormone levels. Or it may change the speed that your body ticks over (your metabolic rate). Or it may even change the length of time food stays in your bowel.

Aspirin and NSAIDs

Aspirin and drugs called non steroidal anti inflammatory drugs (NSAIDs, such as ibuprofen or Nurofen) may help to prevent bowel and other digestive system cancers. A 2010 review of trials found that taking low dose aspirin for a few years reduced the risk of colon cancer but not rectal cancer. Research is looking into using medicines such as aspirin to prevent bowel cancer. But aspirin does have side effects. You should not take aspirin or other NSAIDs regularly without checking with your doctor first.

Other possible protective factors

Hormone replacement therapy (HRT) and the contraceptive pill may protect against bowel cancer. You may have a lower risk of bowel cancer if you have a higher than average level of vitamin D and if you don't smoke.
 

CR PDF Icon You can view and print the quick guides for all the pages in the about bowel cancer section.

 

 

Exercise

Image of a couple walking

People who are more physically active have a lower risk of colon cancer. Overall, the most active men can reduce their risk of colon cancer by nearly 20 to 30%. And the most active women can reduce their risk by around 10 to 30%. In 2011, it was estimated that more than 5 out of 100 bowel cancers (5%) in the UK were linked to people doing less than 150 minutes of at least moderate exercise per week.

We don't know why exercise helps. It may affect your hormone levels. Or it may change the speed at which your body ticks over (your metabolic rate). Or it may even change the length of time food stays in your bowel.

 

Aspirin and NSAIDs

Non steroidal anti inflammatory drugs (NSAIDs, such as ibuprofen) and aspirin may help to prevent bowel and other digestive system cancers. We don't know quite how this works. There is a theory that this type of drug stops an enzyme called COX-2 from working. Blocking the enzyme may help to stop polyps developing. Polyps can develop into cancer. Trials are looking into this further. 

At least 2 trials using aspirin have found it lowers the risk of developing bowel polyps. A 2010 review of trials found that taking low dose aspirin for a few years reduced the risk of colon cancer but not rectal cancer. It also reduced the number of people who died from bowel cancer. But aspirin does have side effects and it is not yet clear how safe it is to take even low doses. Research is looking into this. 

You should not take aspirin or other NSAIDs regularly without checking with your doctor first. These drugs can damage the lining of your stomach and cause bleeding. Doctors don't currently recommend routinely taking aspirin or other NSAIDS to prevent bowel cancer unless you are part of a clinical trial. For many people, the risk of damage to the stomach lining outweighs the benefit of preventing bowel cancer. 

Some cancer prevention trials are listed on our clinical trials database. If you want to search only for prevention trials, you will need to use the advanced search option.

 

HRT and the Pill

Hormone replacement therapy (HRT) and the contraceptive pill may protect against bowel cancer, but the evidence is mixed. Compared with women who have never used them, the evidence suggests that women who have used HRT or the pill have around a 20% lower risk of colon and rectal cancer. But we need more research to be sure.

Female hormones may protect against bowel cancer by helping to lower the concentration of bile in the bowel. Although we need it for the healthy digestion of fats, bile irritates the lining of the bowel.

Although HRT may reduce bowel cancer risk, there are other health issues to take into account when deciding to take HRT. It increases your risk of breast cancer and other illnesses. Before making a decision about whether to take HRT, you should talk to your doctor about the overall effect it could have on your health.

 

Vitamin D

Several studies have shown that people with higher levels of vitamin D have a lower risk of bowel cancer. You get a small amount of vitamin D from your diet. But your body also makes vitamin D in response to the sun. You don't need to sunbathe to get enough vitamin D. A short time outdoors a few times a week should be enough. Your body only makes as much vitamin D as it needs. So spending too long in the sun and getting burnt will not help with vitamin D levels, but will increase your risk of skin cancer.

 

Bowel cancer screening

We know from research that people taking part in bowel screening programmes using the faecal occult blood test have a 16% lower risk of dying of bowel cancer than people who don't have screening.

 

Not smoking

Smokers are more likely to develop polyps in their bowel than non smokers, and some studies show that smokers have a higher risk of bowel cancer, particularly rectal cancer. So giving up smoking can reduce your risk of bowel cancer. If you want to give up smoking you can find tips and information on this website.

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Updated: 30 September 2013