What is dietary fibre?
There are many different types of fibre, but there are two main groups, soluble and insoluble. Each group helps your body in different ways so it is important to include both in your diet.
Soluble fibre (also known as fermentable fibre) is found in:
- grains such as oats, barley and rye;
- fruits like bananas and apples;
- beans and pulses, like baked beans and chick peas;
- root vegetables like carrots and potatoes.
Soluble fibre dissolves in water and forms a gel in the gut. It helps to keep stools soft, making them easier to pass, which may help prevent or treat constipation.
Insoluble fibre (also known as partially fermentable fibre) is found in:
- cereal foods like high fibre breakfast cereals;
- wholemeal breads and pasta, brown rice and other wholegrains;
- vegetables, potatoes with skins;
- nuts, and seeds.
How does fibre benefit health?
Dietary fibre has many health benefits. It can reduce your risk of heart disease, diabetes and some cancers, and also help weight control. Fibre is also important for digestive health - insoluble fibre bulks up stools and makes waste move through the digestive tract more quickly, which is better for the gut and can help to prevent constipation. Soluble fibre may also help this process by making the stools softer and easier to pass. Some types of fibre can be fermented by gut bacteria, producing substances that appear to be good for gut health. Providing ‘food’ for gut bacteria can also help increase the number of healthy bacteria in the gut.
If you need to increase your fibre intake, it is a good idea to so gradually, especially from foods providing insoluble fibre. It is also important to drink plenty of fluids (8-10 glasses per day for adults) and to try to be active for at least 150 minutes per week. See How much physical activity do I need?
Consuming fibre-containing foods seems to be protective against colorectal cancer – this may be because fibre helps waste products to move more quickly through the gut and also due to the fermentation of certain fibres by ‘friendly bacteria’.
Soluble fibres such as beta-glucans and pectins, can help reduce blood cholesterol, so eating plenty of foods like oats, fruit, root vegetables and pulses is a good idea, particularly if you know you have a high cholesterol level or other risk factors for heart disease.
How much fibre do we need?
The government published new guidelines in July 2015 on carbohydrates and health, and recommends that the population's fibre intake should increase to 30g a day (measured by the AOAC method) for adults. On average, we consume much less than this - about 18g per day. Intakes of fibre in children are low too, so recommendations have also been set for children aged under 16 years.
|Age (years)||Recommended intake of fibre|
|2-5||15g per day|
|5-11||20g per day|
|11-16||25g per day|
|17 and over||30g per day|
A healthy, balanced diet can provide enough fibre – especially if you eat your 5 A DAY and choose wholegrain foods and potatoes in skins. Below is an example of foods that together provide more than the recommended amount of fibre over a day.
|Time||Food||Quantity||Fibre content (g)|
|1 banana, sliced||100g||1.5|
|wholemeal toast (2 slices)||70g||4.7|
|Dinner||Baked potato with skin, tuna mayonnaise||180g||6.5|
|Salad (lettuce, tomato and cucumber)||138g||1.7|
|Low fat yogurt||150g||0|
|and chopped almonds||13g||1.3|
|Total fibre intake||34.4|
To increase your fibre intake you could:
- Choose a high fibre breakfast cereal e.g. bran flakes, or porridge
- Go for wholemeal or granary breads instead of white bread
- Choose wholegrains like wholewheat pasta, bulghur wheat or brown rice
- Go for potatoes with skins e.g. baked potato or boiled new potatoes
- For snacks try fruit, vegetable sticks, rye crackers, oatcakes, unsalted nuts or seeds
- Include plenty of vegetables with meals – either as a side dish or added to sauces, stews or curries
- Add pulses like beans, lentils or chickpeas to stews, curries and salads
- Have some fresh or dried fruit, or fruit canned in natural juice for dessert.