By Elizabeth Hartland
What is dietary fibre and why is it important?
Fibre itself has no nutritional value but the foods in which it is found have vitamins and minerals. It is found in grains, pulses, beans, nuts, vegetables and fruit but not in meat, fish or dairy products. There are two main types – water insoluble and soluble and each plays a different, yet important function in the body.
Water insoluble fibre such as cellulose found in bran and the plant cell walls of foods, cannot be digested by the body. It passes straight through, absorbing water like a sponge. This adds bulk to the waste material in the body. The bulk stimulates the muscular contractions which push the food steadily along the intestines. When the final waste matter is formed, the stools should be large, soft and float as well as easy to pass.
Too little water insoluble fibre and insufficient liquid results in small, hard stools that are difficult to pass and may lead to constipation. The muscles find it difficult to push along small, hard waste matter so straining occurs. Also, when matter stays too long in the bowel, infection and disease may result.
Soluble fibre has been shown to restrict the amount of fat absorbed from food and can significantly lower the blood cholesterol level. This in turn helps to prevent heart attacks.
Fibrous foods need a lot more chewing, absorbing water, bulking out the stomach, making you feel fuller so less is eaten. High fibre foods have a lower calorie content, often replacing fatty refined foods so are useful if overweight. The extra chewing involved also helps to improve dental health.
Why eating dietary fibre can help break the sugar habit
Sugar consumption disturbs our blood sugar levels, e.g. we eat sugar and it rushes quickly into the blood as glucose, giving us a temporary high. Our tired pancreas releases insulin which lowers the glucose, but often too low (result of a high sugar diet), often leading to apathy, dizziness, weakness, fatigue and sometimes depression. This urges us to crave sugar, temporarily relieving these symptoms and the vicious circle continues.
So to help reduce sugar cravings it is important that sugars in our food are released gradually with no sudden rushes of glucose.
Fibre can help do this
1) It packages starchy foods in the stomach and small intestine, delaying absorption of glucose.
2) Pectin – a soluble fibre slows down absorption of glucose (found in bananas and apples).
3) Certain beans contain gums, also slowing down glucose absorption.
4) Beans contain polyphenols again slowing down glucose absorption.
5) Eating more fibre means there is less room for sugary refined foods, helping to wean you off it.
How much fibre is needed?
The average figure recommended is at least 30 grams a day, but it is best to say that you are getting enough when you pass soft stools without any straining at least once a day, though 2-3 times a day is considered healthiest.
Can you eat too much fibre?
Initially, when you change to a high fibre diet you may experience some abdominal discomfort with more flatulence or slight diarrhoea – do not be concerned unduly as this will remedy itself.
||Examples of foods high in fibre (expressed in grams of fibre per 100g of food)
Fresh Coconut 13.6
Brown Boiled Rice 5.5
White Boiled Rice 0.8
Soya flour 14.3
Wholemeal Bread 6.5
White Bread* 2.2
Shredded Wheat 12.3
Rice Crispies 1.0
Oat Cakes 4.0
Baked Beans (canned) 7.3
Lentils (boiled) 3.7
Broad Beans 4.2
Peanut Butter 7.6
Steamed Broccoli 4.1
Raw Cabbage 3.4
Steamed Carrots 3.1
Raw Parsley 9.1
Peas (Raw or Fresh) 5.2
Potatoes in skins 2.0
Dried Raisins 6.8
Dried Figs 18.5
Dried Prunes 16.1
Boiled Sweets 0
Sponge Cake 1.0
Bread and Butter Pudding 0.6
Elizabeth Hartland has a Bachelor of Science Degree in nutrition, together with a Diploma from the Institute of Nutritional Therapy. She is married with two young children and has a passion for good nutrition and helping others to find better health. 282 427 652