Does a high fibre diet reduce my risk of cancer?

  • Yes, eating a diet with lots of foods high in fibre, including wholegrains like wholemeal bread or brown rice, reduces your risk of bowel cancer
  • Around 9 in 10 people in the UK are not meeting the recommended amount of 30g of fibre a day
  • By making some simple swaps you can up your fibre intake

What is fibre?

Fibre is a type of carbohydrate (carb) found in plant-based foods. You might have heard it described as roughage. When we eat it, we can’t easily break it down, so it moves through our gut into the bowel.  

Based on what we know so far, it seems the fibre from wholegrains is better at reducing cancer risk than fibre from fruits and vegetables. But it’s important to eat both as part of a healthy balanced diet.



How does fibre reduce bowel cancer risk?

There are several ways that fibre could reduce your risk of bowel cancer.

Fibre helps us to poo more often, increases the size of poos and dilutes their contents. This means harmful chemicals spend less time in the bowel.

When fibre meets the bacteria in the bowel, the bacteria make something called butyrate. Butyrate helps the cells in our bowel to stay healthy, so that tumours are less likely to develop.


How can I fit in more fibre?

Foods that are high in fibre include wholegrains, fruit, vegetables and pulses (such as beans or lentils). All these foods are high in fibre, but the strongest evidence for a reduced risk of cancer is for wholegrains.

Wholegrains are things like brown rice, whole wheat pasta, oats and wholegrain bread.

To up your fibre intake try;

  • Switching everyday items such as bread, pasta or rice to their wholegrain or brown alternative
  • Having fruit and vegetables with every meal (they can be fresh, frozen or tinned)
  • Using lentils or beans in the place of some or all the meat in your favourite dishes
Top tip - Don’t get caught out when buying your weekly loaf. Most multi seed breads aren’t wholegrain. A good tip when shopping for wholegrains is to look out for ‘whole’ before wheat in the ingredients list.


Should I take fibre supplements?

Though fibre supplements may be useful for some people with certain medical conditions, for most of us the best way to up our fibre intake is by making changes to our diet and eating more food high in fibre, particularly wholegrains. The evidence so far has looked at fibre in what we eat, rather than in supplements, to show its the health benefits of fibre.


Wcrf, Aicr. Diet, Nutrition, Physical Activity and Cancer: a Global Perspective. A summary of the Third Expert Report 2018.

World Cancer Research F. Diet, nutrition, physical activity and colorectal cancer. : World cancer research fund; 2017.

Brown KF, Rumgay H, Dunlop C, et al. The fraction of cancer attributable to modifiable risk factors in England, Wales, Scotland, Northern Ireland, and the United Kingdom in 2015. British Journal of Cancer. 2018;118:1130-1141.

World Cancer Research F. Wholegrains, vegetables and fruit and the risk of cancer. Continuous Update Project.


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