Dietary fibre: key for a happy, healthy gut

The gut plays a big role in your total health, so eating more fibre-containing foods has many health benefits. Try to eat more whole grains, fruits, vegetables, dried beans and lentils each day.

Fibre is the part of food that is not digested in the small intestine. Dietary fibre moves largely unchanged into the large intestine or colon where it is fermented by friendly bacteria that live there. But there are different types of fibre, all with a role to play.

Eating foods high in fibre

Australians need to eat at least 25-30g fibre each day. Eating more dietary fibre can help keep your digestive system healthy and reduce the risk of:

There is also a link between eating high fibre whole grain foods and a lower risk of cardiovascular disease.

There are two kinds of fibre – insoluble and soluble.

Insoluble fibre

Insoluble fibre adds bulk, and helps to keep our bowels regular. It’s found in the hard, scratchy outer skins and surfaces of roots, grains and seeds which are not as easily digested. Insoluble fibre is also very filling. This type of fibre works like a ‘broom’ through the bowel. Foods higher in insoluble fibre include:

  • Whole grain breads and cereals
  • The outer skins of fruit and vegetables
  • Nuts and seeds
  • Raw lentils, kidney beans and chickpeas.

Soluble fibre

Soluble fibre dissolves in water to form a thick gel in your intestines, slowing down digestion. Foods containing this type of fibre can help stabilise blood glucose levels in people with diabetes and may help to lower LDL (unhealthy) cholesterol levels by collecting fatty deposits as it moves through the intestine. By slowing down digestion, foods that are high in soluble fibre can help people feel fuller for longer after eating. Foods higher in soluble fibre include:

  • Fruits and vegetables
  • Dried beans and lentils
  • Oats.

Resistant starch

While most starch is digested in the upper part of the gut, resistant starch resists digestion in the small intestine and so goes all the way to the large intestine. Once in the large intestine, friendly bacteria ferment resistant starch. This process produces substances (gasses) that help to keep the lining of the bowel healthy. Resistant starch can be found in:

  • Slightly undercooked pasta (‘al-dente’)
  • Under ripe bananas
  • Cooked and cooled potato
  • ‘Hi-maize’ which is found in commercial food products such as breads and cereals.

Below is an example of how an adult may meet their daily dietary fibre requirements:

Food
3/4 cup whole grain breakfast cereal
2 slices wholemeal bread
1 apple (with skin) and 1 orange
2 cups mixed raw vegetables
1/4 cup legumes eg. baked beans
Total

Fibre Content
4.5g
4.5g
5.5g
10g
3g
27.5g

An Accredited Practising Dietitian (APD) can offer advice on how best to eat a variety of high fibre foods each day and getting the balance of fibre that is right for you.