Protecting against 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
People who do more physical exercise have a lower risk of large bowel (colon) cancer. We don't know exactly how exercise helps. It may be because exercise can affect your hormone levels. Or because doing exercise speeds up the length of time food stays in your bowel. This reduces the amount of time the bowel lining is in contact with harmful chemicals such as those released when you drink alcohol or eat red or processed meat.
Studies have found that taking aspirin regularly lowers the risk of developing bowel growths (polyps) and bowel cancer. But aspirin has side effects. And it is not yet clear how safe it is to take regularly, even at low doses. Research is looking into this. You should not take aspirin 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.
You can view and print the quick guides for all the pages in the about bowel cancer section.
People who are more physically active have a lower risk of bowel cancer. There is more evidence for cancer of the large bowel (colon cancer) than cancer of the back passage (rectal cancer). About 3 out of 100 bowel cancers (3%) in the UK are linked to not doing enough exercise.
We don't know exactly how exercise helps. It may be because it affects your hormone levels. Or because it changes the speed at which your body ticks over (your metabolic rate). Or because doing exercise speeds up the length of time food stays in your bowel. This reduces the amount of time the bowel lining is in contact with harmful chemicals such as those released when you drink alcohol or eat red or processed meat.
Studies have found that regular use of aspirin lowers the risk of developing bowel polyps and bowel cancer. But aspirin has side effects and it is not yet clear how safe it is to take regularly, even at low doses. Research is looking into this.
You should not take aspirin regularly without checking with your doctor first. It can damage the lining of your stomach and cause bleeding. Doctors don't currently recommend routinely taking aspirin 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.
Hormone replacement therapy (HRT) and the contraceptive pill may protect against bowel cancer. Compared with women who have never used them, the evidence suggests that women who have used HRT have a 16% lower risk of bowel cancer. And those who have used the pill have up to a 20% lower risk of bowel cancer.
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.
Read more about hormones and cancer.
Some 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.
Alcohol increases the risk of bowel cancer. So cutting down on the amount you drink could reduce the risk. About 11 out of 100 bowel cancers (11%) in the UK are linked to drinking alcohol.
The risk of bowel cancer goes up with the more alcohol you drink. But even fairly small amounts can have an effect. The EPIC study found that for every 2 units a person drinks each day (less than a pint of premium larger or large glass of wine), their risk of bowel cancer goes up by 9%.
Read more about alcohol and cancer.
The International Agency for Research on Cancer (IARC) classifies smoking tobacco as a cause of bowel cancer. The risk increases with the number of cigarettes you smoke each day. Smokers are also more likely to develop polyps in their bowel than non smokers.
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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