Roughly speaking – dietary fibre
Dietary fibre is something we should eat more of! Isn’t that great, we are actually being told that we should eat more of something rather than being told that we are to cut back! In order to do this we need to know what fibre is and where to get it.
Dietary fibre is a term that incorporates many different parts of the plants that we eat, but is probably best defined as those parts of plants that are resistant to digestion in the stomach and gut. In other words, it does not get absorbed. You can only get fibre from plant products, but there are different types and amounts of fibre in everything we eat. For example white bread has very little fibre but whole wheat bread is a good source.
Dietary fibre was once known as ‘roughage’, but now has a new name — non-starch polysaccharide (NSP). There are two broad categories of fibre, or NSPs that you may see on food labels, called insoluble and soluble. This simply refers to the ability of these to dissolve in hot water.
We need a mix of both, and most diets contain about 2/3 insoluble and 1/3 soluble fibre. Insoluble fibre assists in maintaining regular bowel movements while soluble fibre lowers blood cholesterol levels and can help regulate blood sugar concentrations.
The main function of insoluble fibre is as a bulking agent and so it helps prevent constipation and keep the large intestines healthy. Wholegrain cereals and wholemeal bread are particularly good sources of this type of fibre. Most people do not eat enough dietary fibre. The average intake in Britain is 12g per day and it is recommended that this rises to 18g for adults.
Children need less as too much fibre can make a young child’s diet so bulky that they become full before they have eaten sufficient food to satisfy their need for essential vitamins, minerals and energy.
Fibre is made of mostly complex carbohydrates that are sugar molecules linked in a way that our digestive enzymes don't break them apart. Fibre increases dietary bulk, making chewing more work, and giving a feeling of fullness.
A classic experiment in the fibre field was done more than 20 years ago and is still one of the best examples of its benefits - If you squeeze two apples, you get a glass of juice that you can drink in 30 seconds and you may feel hungry half an hour later. If you cook the two apples to make apple sauce, you can eat this in a few minutes and you will feel hungry one or two hours later. But if you eat two apples, it will take you 20-30 minutes and you won't be hungry for several hours.
Convinced yet? Well why not try to substitute some of the foods that you eat normally with some that have higher fibre. You will probably hardly notice the difference and yet you’ll be doing yourself some good!
Here are some of the high scorers when it comes to fibre full foods!
Wholemeal bread - 1.93g per slice
White bread - 0.58g per slice
Weetabix - 3.9g per serving (2 biscuits)
Kelloggs All Bran - 10g per serving (40 g)
Boiled wholemeal pasta - 7.7g per serving
It's worth noting that recent fibre studies where the fibre is given as supplements rather than foods do not show the same benefits.