Fibre & Cancer Risk

In recent years, many scientific studies have suggested that cancer development may be linked with food consumption. Indeed, it is estimated that one in ten cancer diagnoses may be attributed to unhealthy diets. Several foods have been suggested to contribute to cancer including those that contain high levels of saturated fats and low levels of fibre. At present a large international study called EPIC (European Prospective Investigation into Cancer and Nutrition) is investigating the links between diet and cancer. EPIC scientists have recently discovered that foods high in fibre can reduce risk of bowel cancer.

What is dietary fibre?

beans-insoluble-fibre-foods

Fibre is defined as ‘dietary material containing substances such as cellulose, lignin and pectin, that are resistant to the action of digestive enzymes’ (Oxford Dictionary). Fibre contributes to a healthy diet and provides many health benefits including prevention of: heart disease, diabetes, weight gain and cancer and can also improve digestive health. However, statistics reveal that the average UK fibre consumption is lower (approximately 14 g) than the daily recommendation (18 g).

Fibre exists in two forms, soluble and insoluble, and each contribute to the body in different ways thus both are important for a balanced diet. Soluble fibre dissolves in water and is thought to reduce the levels of blood cholesterol in the body and soften stools allowing easier passage through the bowels. Foods that contain soluble fibre include: oats, barley, rye, bananas, apples, root vegetables and linseeds. Insoluble fibre passes through the digestive system without being broken down and aids movement of other foods through the bowels thus maintaining a healthy gut and preventing digestive problems. Foods that contain insoluble fibres include: wholemeal bread, bran, cereals, nuts and seeds.

How is fibre protective against bowel cancer?

Although fibre has been associated with reduced risk of bowel cancer development, the mechanism through which this may occur remains elusive. It is thought that bacterium in the bowel may interact with fibre to produce several chemicals including butyrate. Butyrate causes a change in bowel conditions which reduces the risk of tumour development and experiments have revealed that butyrate can stop the growth of cancer cells resulting in cell death. Furthermore, it has also been suggested that dietary fibre may increase the weight of stools and frequency of bowel movement. This reduces the contact time between the bowel and chemicals found within stools and may thus reduce cancer development.

Eating lots of fibre could reduce the risk of bowel cancer

EPIC scientists have revealed that people who consumed 25 – 40 % of daily recommended fibre correlated with a lower risk of bowel cancer compared to people who consumed lower percentages. Other large scale studies have supported these findings and showed that a diet low in fibre contributed to more than one in ten bowel cancers. However, results have proven controversial and some studies do not show a link between high fibre diets and bowel cancer risk. This may have been because of the methodological limitations of studies looking at populations from single countries which may have low average fibre consumption or the level of fibre intake studied may have been too low. However EPIC scientists have tried to overcome these limitations through the investigation of fibre consumption in 10 European countries thus aiming for more reliable results.

Conclusions

Although several food groups are associated with cancer risk, scientists are yet to determine specific foods which show a convincing contribution to cancer development. This may be due to the difficulties scientists face in the analyses of individual’s daily diets which are highly variable and consist of multiple food groups that differentially affect the risk of cancer development. Therefore, whilst it has been well established that foods high in saturated fats and low in fibre may increase bowel cancer risk, it is a challenge for scientists to design experiments that can accurately pinpoint the singular effect of individual foods. Overall, evidence suggests that it is important to maintain a healthy well-balanced diet consisting of high fibre foods that may reduce the risk of bowel cancer development and improve digestive health.

3 thoughts on “Fibre & Cancer Risk

  1. Melissa says:

    What a coincidence, I am doing an assignment on this exact topic right now! I’m reassured by the fact that the logic of my assignment is very similar to the logic of your article 🙂

    Like

    • Becky says:

      Hi Melissa, that’s great! I’m glad it can be of some use to you 🙂 Good luck with your assignment and thank you for reading my article 🙂

      Like

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