Herbal & Plant

Fibre is a type of carbohydrate found in plant foods which we do not have the ability to digest in the same way as we digest protein, carbohydrate and fat. Fibre can be conveniently divided into two types: Insoluble and soluble fibre.

 

Insoluble fibre

This type of fibre is the one most recognised and is typified by the course almost ‘husk’ like fibre as is found in wheat bran. It does not become particularly viscous when added to water, and passes through both the small and large intestine providing a noticeable laxative effect by adding bulk to the stool, and hence increasing frequency of bowel movement.

Generally speaking, the bulkier the stool the faster and more frequent the bowel movement. Also it is noteworthy that foods rich in insoluble fibre will add about four times the bulk of stool per gram of fibre than most fruits and vegetables. The laxative effect of fibre apart from reducing any symptoms associated with constipation is also linked with decreased colonic pressure and risk of many intestinal diseases.    

 

Soluble fibre

This type of fibre as the name suggests is reasonably soluble in water, sometimes producing viscous gel like substances. Also, although this fibre goes through our small intestine intact, the billions of friendly bacteria in our large intestine ‘ferment’ it to produce beneficial acids such as lactic and butyric acid, and also gas. The acids which are produced are used as food by the cells which line the large intestine and hence provides a major role in maintaining intestinal health, whilst the gas produced is the major source of the 2-4 litres of ‘wind’ which we all pass every day.

Fibre is known to be beneficial to health in a variety of ways. These include;

 

Weight management – studies have shown that fiber, particularly the viscous types of soluble fibre create a feeling of fullness hen eaten and hence blunt the appetite. On average it has been found that an increase of 14g/day of fibre to the diet results in a 10% reduction of calorie intake.

 

Heart health and type 2 diabetes – studies of large populations have associated the increased intake of fibre with lowered risk of heart disease and diabetes. This reduction in risk is due to fibre having a beneficial effect on risk factors such as:

Basically yes they are. Because soluble fibre is used for growth by the friendly bacteria used as probiotics they are now often termed ‘prebiotics’. As such, fibre will contribute to the maintenance of high populations of these friendly bacteria, and therefore contribute to the benefits they provide.

The average amount of fibre consumed per day in the UK is between 12-14g, whereas it is considered that the optimal amount is about double this quantity at 25-30g. The British Nutritional Foundation guideline for fibre intake is 24g/day. For children above 2 years of age a good guideline for fibre intake is ‘age +5g’ /day. For example, a 10 year old should have an intake of 10+5=15g/day.

Clearly, fibre intake can be increased by dietary means by eating greater amounts of fruit, vegetable, and wholegrain products. However, recently a number of soluble fibre products have been introduced into the market as soluble powders which are either tasteless or moderately sweet and which can be added to drinks etc. These do potentially offer a convenient way of increasing fibre intake.