Fibre

Published by Bupa’s Health Information Team, December 2010.

Fibre is an essential part of a healthy diet, helping to keep your digestive system in good working order. But many people aren’t getting enough. This article explains why fibre is important – and how you can make some simple changes to incorporate more of it into your diet.

What is fibre?

Fibre is a type of carbohydrate that is found in all types of plant-based foods, including fruit, vegetables and grains. However, unlike other types of complex carbohydrate, it’s not easily broken down by your digestive system and most of it passes through your body unchanged.

There are two types of fibre – soluble and insoluble. Insoluble fibre passes through your digestive system undigested, whereas soluble fibre is broken down by bacteria in your large bowel.

Why do I need fibre?

Fibre is essential for keeping your bowel healthy. When fibre passes through your bowel, it absorbs a lot of water and increases the bulk of any waste matter that leaves your body. This makes your faeces softer and easier to pass through your bowel.

Some types of fibre also produce a small amount of energy; however this is so little that it isn’t really considered to be an energy source.

Health benefits of fibre

Both soluble and insoluble fibre are beneficial to your health. Insoluble fibre can help to prevent various bowel problems, such as constipation and diverticular disease (when your bowel wall becomes inflamed and damaged). Having a diet high in fibre has also been associated with a reduced risk of bowel cancer. However, there is some debate about whether fibre protects against bowel cancer, or whether people who eat lots of fibre may just have a healthier diet in general, which puts them at a lower risk. Either way, making sure you include lots of insoluble fibre in your diet can help to keep your bowel healthy and functioning well.

Fibre has some other important health benefits in addition to its effects in the bowel. Soluble fibre has been shown to help reduce cholesterol levels, which in turn reduces your risk of heart disease. There is also some evidence to suggest that fibre can reduce your risk of type 2 diabetes. Fibre also slows down the absorption of carbohydrates into your blood – helping to keep your blood sugar level constant. This can be particularly helpful in people who have diabetes.

Finally, foods high in fibre help to make you feel full, control your appetite and to maintain a healthy weight.

Good sources of fibre

All plant-based foods contain fibre, but some have more than others. Good sources of insoluble fibre include:

• wholegrain bread
• wholegrain breakfast cereals
• brown rice
• fruit and vegetables

Good sources of soluble fibre include:

• beans and lentils
• oats
• pulses (eg peas and beans)
• fruit and vegetables

How much fibre do I need?

The recommended intake of fibre for adults is 18g a day. However, most people in the UK don’t eat enough – the average intake is 12.6g a day for women and 15.2g a day for men.

So what does 18g of fibre look like? A few examples of the amount of fibre in some common foods include the following.

• One bowl (30g) of high-fibre cereal, eg bran flakes – 4g
• One slice of wholemeal bread – 3 to 4g (white bread contains less than half this amount)
• One baked potato (with skin) – 5g
• Half a tin of baked beans (200g) – 7.7g
• Portion of dried figs (50g) – 3.8g
• One medium-sized apple – 1.8g

You don’t need to keep track of the amount of fibre in all the food you eat – but if you make wholegrain, starchy foods the basis of all your meals and eat plenty of fruit and veg, you should be well on your way to reaching the recommended amount.

If you do decide to increase your fibre intake, it’s best to do it gradually. Suddenly upping it can lead to wind, bloating and stomach cramps. However, your digestive system will slowly adapt to the increased amount of fibre and any problems will gradually subside. You should also make sure you are drinking enough fluid if you increase your fibre intake, as fibre absorbs water.

Fill up on fibre

Want to get more fibre into your diet? Here are a few tips to help you on your way.

• Go for wholegrain bread, rice and pasta rather than white versions. They are higher in fibre and just as tasty.
• Don’t just rely on fruit juice for your five-a-day. It’s ok to have the occasional glass, but eating whole fruits instead will help to bump up your fibre intake – and they also contain less sugar and fewer calories.
• Try incorporating more pulses – such as beans, chickpeas and lentils – into your diet. They are a very healthy, and often cheap, alternative to meat, being high in protein and low in fat – as well as an excellent source of fibre.
• Dried fruit, nuts, popcorn and raw veg are all examples of high-fibre, healthy snacks.
• Check the labelling - foods that are classed as high fibre must contain at least 6g of fibre per 100g.

For sources and links to further information, see Resources.