Preventing bowel cancer with a high fibre diet
Dietary fibre is the part of plant foods that cannot be broken down and absorbed by the body. It is found in all types of grains, nuts, fruits and vegetables.

The main function of fibre is to keep the digestive system healthy. Dietary fibre can also help with managing your diabetes by slowing the absorption of glucose from the small intestine and reducing cholesterol levels.

How does fibre help to improve my bowel health?
There are two types of fibre found in our food – insoluble fibre and soluble fibre.

Insoluble fibre – adds bulk to the faeces and helps food to pass through the bowel quickly, helping to prevent constipation. Insoluble fibre is found in wholegrain breads and cereals, brans, the skin on fruit and vegetables, as well as nuts and seeds.

Soluble fibre – helps to prevent constipation by soaking up water, just like a sponge. This adds more bulk to the faeces and softens it, helping to pass through the bowel more easily. Soluble fibre is found in oats, barley, legumes (such as lentils, beans, chickpeas, etc.) flaxseeds and psyllium. This type of fibre helps reduce cholesterol levels and can help to reduce blood glucose levels.

How much fibre do I need each day?
It is recommended Australian adults eat around 25-30g of fibre each day. However, most adults do not consume enough fibre, only consuming around 18-25g daily.

A diet low in fibre can increase the risk of the following health problems:

• Constipation will result in small, hard dry faeces that are difficult and painful to pass
• Diverticulitis is when small pouches form in the wall of the small intestine and then become inflamed
• Haemorrhoids are swollen veins in the anus that can become painful
  Irritable bowel syndrome symptoms include stomach pain, bloating, frequent passing of wind and constipation.
• Bowel cancer can develop resulting in cancer of the large intestine.

How can fibre help to prevent bowel cancer?
Many studies have shown a diet high in fibre can help reduce the risk of developing bowel cancer. Fibre increases the bulk of the faeces, possibly diluting some of the cancer-causing components from the diet and also helps the faeces to pass through the bowel more quickly.

When fibre passes through the bowel, it is fermented by bacteria and produces short-chain fatty acids which are thought to protect against bowel cancer.

A diet high in fibre can also help you to lose and maintain a healthy body weight. Foods that are high in fibre are more filling, which may cause you to eat less. Being overweight or obese is a risk factor for developing bowel cancer.

How can I include more fibre in my diet?
Eating the recommended amount of fibre each day (25-30g) is easy if you choose wholegrain breads and cereals and eat the recommended amounts of fruit, vegetables, nuts and legumes. You can follow these simple tips and help boost your fibre intake:

• Eat high fibre breakfast cereals (those that contain greater than six grams of fibre per 100 grams) such as those that contain barley, wheat or oats. Good examples include Weet-Bix, traditional oats made into porridge, natural muesli and All Bran.
• Eat wholemeal and grainy bread, rather than white bread.
• Eat brown rice and wholemeal pasta.
• Include fruit, vegetables or salad (at least five to six serves of vegetables per day) with all of your meals.
• Snack on fresh fruit (two serves per day), nuts or wholegrain crackers.
• Add legumes to your meals, such as lentils in soups and casseroles, chickpeas in salads or enjoy baked beans on toast. It is recommended to have at least two serves of legumes per week. If you need to increase the amount of fibre you eat in order to meet the recommendations, it is important to add fibre gradually to your diet, as a sudden increase can also cause stomach pain and wind. Remember to also increase the amount of fluid you drink.

Fluid
It is important to make sure that you are drinking enough fluid when you have a high fibre diet, as fluid is needed to soften the stool and flush the fibre through the gut. If you don’t drink enough fluid, large amounts of fibre may cause some stomach pain and constipation.

Reducing your risk of bowel cancer is all about having a healthy lifestyle

• Maintain a healthy weight
• Eat a high fibre diet, with plenty of wholegrain breads and cereals, fruit, vegetables, legumes and nuts.
• Don’t smoke
• Exercise will help the movement of waste products through your bowel and will also assist in managing your weight.

For more information about bowel cancer, contact the Cancer Council on 13 11 20.