Fibre

According to the National Health and Medical Research Council (NHMRC) in their recommendations for nutrient reference values, the daily fibre intake for adult women should be at least 25g a day, and at least 30g for men. There are good reasons to aim for 30g or even higher if you can. High-fibre diets can help prevent bowel problems such as constipation, irritable bowel syndrome and even cancers.

The NHMRC also suggests that by increasing fibre intake to 38g per day for men and 28g per day for women, there may be further reduction of the risk of developing chronic conditions such as heart disease and diabetes.

What is fibre?

Fibre (sometimes known as ‘roughage’) refers to the parts of plant-based foods that your body can’t fully digest. It’s found in the cell walls of plants. Foods from animal products such as meat, fish, eggs and dairy contain no fibre at all. Fibre can be roughly divided into three different types:

• Insoluble fibre, which is good for bowel health. This type can be found in brans, wholegrain cereals including brown rice, and wholegrain breads.
• Soluble fibre, which helps lower cholesterol and keep blood sugar levels healthy. This kind is found in legumes like lentils and beans, and vegetables and fruit.
• Resistant starch, which is bowel-healthy, like insoluble fibre. This type can be found in whole grains, firm bananas, legumes, al dente pasta and cooked, cooled potatoes.

Why is fibre so important?

Insoluble

When insoluble fibre passes through your bowel, it absorbs a lot of water and increases the bulk of any waste matter. It also makes the waste softer, increasing the speed and ease with which it passes through your bowel.

By promoting a healthy bowel, a fibre-rich diet reduces the risk of bowel problems, including constipation and diverticular disease (when the bowel wall becomes inflamed and damaged). A high fibre diet may also reduce the risk of bowel (colon) cancer.

Soluble

Soluble fibre also helps to stabilise your blood sugar levels as it slows down the rate at which glucose is absorbed into your blood stream. Along with a balanced diet with low glycemic index (GI) foods which take longer to break down in the blood stream, this can help keep your energy levels consistent throughout the day, and prevent sharp swings in blood sugar levels that can adversely affect your health in the long run. Maintaining a healthy blood sugar level is particularly helpful if you have diabetes or pre-diabetes.

Soluble fibre also helps to lower your blood cholesterol levels, which in turn reduces your risk of heart disease.

Resistant starch

Fibre also makes you feel full which can help with appetite control if you’re trying to lose excess weight. Resistant starch is believed to provide food for ‘friendly’ microbes in your intestine. The friendly microbes produce a substance called butyrate which improves the acid balance of the colon. This helps the healthy microbes to grow while deterring unhealthy microbes from flourishing.

How can I get more fibre into my diet?

• Read nutrition labels on packaged foods — a food with 3g of fibre per serve is classed as a good source of fibre while one with 6g per serve is classed as a very good source
• Start the day with a good muesli based on oats, nuts, seeds and dried fruit, or try a high fibre breakfast cereal. These can give you around 6g of fibre while little extras like two tablespoons of ground linseed will give you another 4g, and half a small apple (with the skin on) an extra gram.
• Legumes are very high in fibre. Half a 400g can of borlotti beans (drained) added to a salad gives 8g, half a cup of green peas will add 4g and a bean-based soup can provide you with as much as 12g of fibre per serve.
• The fibre content of bread varies, but some can give you as much as 9g of fibre in a serve (2 slices). Make sure to read the label as different breads will provide different amounts of fibre per serve.
• Choose high-fibre snacks. A handful of nuts has around 2–3g fibre, whereas a packet of chips has only 0.9g in comparison. Fruit is good but some have more fibre than others. For example, pears have around 5g of fibre compared to 3g in an apple.
• Try a grain-based salad for a change. For instance, a salad based on quinoa or bulgur with some diced vegetables and a few nuts has around 6–8g of fibre.

It’s best to increase your fibre intake gradually. A sudden increase may produce wind or flatulence, bloating and stomach cramps. It's also a good idea to drink plenty of fluids so the fibre has something to absorb, otherwise you may become constipated.

For more information

Dietitians’ Association of Australia (DAA) http://www.daa.asn.au

Sources

Better Health Channel. Fibre in food. [online] Melbourne, VIC: State Government of Victoria. c1999-2010 [updated May 2010, accessed 4 Aug 2010] Available from: http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/fibre_in_food

Cancer Council. Position statement: Fibre, wholegrain cereals and cancer prevention. [online] Kings Cross, NSW; Cancer Council. Nov 2008 [accessed 4 Aug 2010] Available from: http://www.cancercouncil.com.au/

National Health & Medical Research Council. Nutrient Reference Values - Dietary Fibre. [online] Canberra, ACT: Commonwealth of Australia. c2009 [accessed 4 Aug 2010] Available from: http://www.nrv.gov.au/nutrients/dietary%20fibre.htm

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