Dietary fibre
What is fibre?
Dietary fibre is a component of all plant materials. It is mainly made up of types of carbohydrate that your body can’t digest or absorb, and is found in cereals such as wheat bran and oat bran, legumes (e.g. lentils, beans and peas), nuts, and fruits and vegetables. Foods such as meat, fish, eggs, milk and cheese do not contain fibre.
A diet that’s high in fibre is good for your health. High-fibre diets can help:
- prevent and relieve bowel problems such as constipation, haemorrhoids, diverticular disease, and irritable bowel syndrome;
- improve cholesterol levels in the blood;
- reduce your risk of heart disease;
- reduce your risk of diabetes; and
- reduce your risk of certain types of cancer developing.
Fibre and weight loss
Eating food that’s high in fibre can also help if you’re trying to lose weight. That’s because foods that are higher in fibre make you feel fuller for longer; take longer to chew, reducing meal size; and tend to be less energy-dense than other foods, meaning that they contain fewer kilojoules for the same amount of food.
Soluble and insoluble fibre
Fibre is classed as either soluble or insoluble, depending on whether or not it dissolves in water. Insoluble fibre — sometimes referred to as roughage or bulk — is the best type for relieving constipation because it increases stool volume, as well as the movement of material through your digestive system. Good sources of insoluble fibre include whole-wheat flour, wheat bran, certain vegetables, and nuts.
On the other hand, soluble fibre is the best type of fibre for improving cholesterol and blood sugar levels. This type of fibre combines with water to form a gel-like material, and can help slow down the absorption of sugar. It is found in foods such as oats, citrus fruit, barley and beans.
How much fibre is enough?
According to the Nutrient Reference Values for Australia and New Zealand (developed by the National Health and Medical Research Council (NHMRC) and the Department of Health), adult women should eat at least 25 grams of fibre daily, while men should eat at least 30 grams. Pregnant women over the age of 18 should consume 28 grams of fibre every day, and women who are breastfeeding need 27-30 grams each day.
The NHMRC has also stated that increasing fibre intake even further — up to 38 grams per day for men and 28 grams per day for women — may reduce the risk of developing chronic disease (such as cardiovascular disease and diabetes). And if you get this added fibre by adding extra legumes, fruit and vegies to your diet, you will also increase your intake of antioxidant vitamins and folate, further improving the health benefits.
Unfortunately, most Australians only get about two-thirds of the daily fibre they need, and many people are unsure which foods can help boost their daily dose of fibre.
How can I increase my fibre intake?
Here are some tips for increasing your fibre intake:
- Try changing from white bread to whole-grain or multi-grain bread.
- Substitute white rice and pasta with brown rice and whole-wheat pasta.
- Eat a breakfast cereal that contains lots of oats or bran.
- Try to fit in at least 5 serves of vegies and 2 serves of fruit every day.
- Add beans or lentils to a casserole.
- Instead of chips or chocolate, eat a handful of nuts for a healthy snack.
The amount of soluble and insoluble fibre varies in different foods, so it’s best to eat a wide variety of high-fibre foods. And while it’s possible to increase your fibre intake with fibre supplements, these supplements don’t contain the vitamins, minerals and other nutrients that are found in foods.
When you are buying packaged foods, it’s important to remember that not all foods that are labelled as ‘high in fibre’ actually contain a lot of fibre. It’s safest to read the food label to check just how many grams of fibre they contain.
Also, if you are planning on increasing the amount of fibre you eat, it may be wise to increase it slowly to reduce bloating and gas. Try adding in the additional fibre over a period of a couple of weeks. And remember to drink plenty of fluids too — this helps the fibre pass through your system.
What is the fibre content of different foods?
Take a look at our table to find out the approximate fibre content of some different foods.
| Fibre content of different foods | |
|---|---|
| Food | Total fibre in grams (g) |
| Bread | |
| Bread, rye, 1 slice | 2.0 g |
| Bread, whole-wheat, 1 slice | 1.9 g |
| Bread, multi-grain, 1 slice | 1.8 g |
| Bread, raisin, 1 slice | 1.1 g |
| Bread, Italian, 1 slice | 0.9 g |
| Bread, white, commercial, 1 slice | 0.6 g |
| Breakfast cereals | |
| All Bran, 45 g — 1 serve | 12.4 g |
| Sultana Bran, 45 g | 6.4 g |
| Just Right Original, 45 g — 1 serve | 3.8 g |
| Instant porridge, 1 sachet | 3.4 g |
| Weet Bix, 2 biscuits | 3.3 g |
| Cornflakes, 45 g | 1.2 g |
| Rice Bubbles, 45 g | 0.5 g |
| Fruit | |
| Pear (medium), with skin | 5.1 g |
| Mango | 4.1 g |
| Apple (medium), with skin | 3.3 g |
| Orange (medium) | 2.4 g |
| Banana (medium) | 1.9 g |
| Strawberries, 5 | 1.3 g |
| Vegetables | |
| Green peas, 1 cup | 8.8 g |
| Potato (medium), baked, skin on | 4.6 g |
| Sweet corn, off cob, 1 ear | 4.5 g |
| Parsnip, 0.5 cup, slices — 80 g | 2.8 g |
| Sweet corn, canned, 110 g | 2.3 g |
| Potato, peeled and boiled | 1.9 g |
| Carrot (medium) | 1.8 g |
| Tomato, raw | 1.5 g |
| Nuts | |
| Pistachio, 100 g | 9.0 g |
| Almonds, 100 g | 8.8 g |
| Brazil, 100 g | 8.5 g |
| Mixed tree nuts, 100 g | 7.7 g |
| Walnut, 100 g | 6.4 g |
| Cashew, 100 g | 5.9 g |
| Legumes | |
| Lentils, 1 cup | 15.6 g |
| Baked beans, tinned, 1 cup | 13.9 g |
| Red kidney beans, tinned, 1 cup | 13 g |
| Snacks | |
| Muesli bar, fruit, 100 g | 4.0 g |
| Popcorn, air-popped, 3 cups | 3.6 g |
| Mars bar | 0.9 g |
| Potato chips, plain, 10 chips | 0.8 g |
| Cheese crackers, 4 | 0.3 g |
| Pasta and rice | |
| Spaghetti, whole-wheat, cooked, 1 cup | 6.3 g |
| Rice, brown, cooked, 1 cup | 3.5 g |
| Spaghetti, white, cooked, 1 cup | 2.4 g |
| Rice, white, long grain, cooked, 1 cup | 0.9 g |
Last Reviewed: 02 December 2009
- 1. National Health and Medical Research Council (NHMRC). Nutrient reference values for Australia and New Zealand including recommended dietary intakes (published 2006, endorsed by NHMRC 2005, September 9). Available at http://www.nhmrc.gov.au/publications/synopses/n35syn.htm (accessed 2009, Dec 21)
