Dietary Fibre

Fibre is an important part of a healthy and balanced diet.  It has many health benefits – it can help to reduce your risk of heart disease, diabetes, some cancers, it improves digestive health and also helps weight control.  There are two types of fibre – soluble and insoluble. Both help the body in different ways; it is then important that both are included in the diet in order to aid our bodies in its daily processes.

Fibre comes from plants. Meat and dairy products do not contain fibre.  Fibre is a dietary material that is resistant to the action of digestive enzymes.  It is the indigestible part of plant cells.

Fibre absorbs water and swells up during its journey through the digestive tract; this provides good soft bulk that speeds up the transit of food.  Fibre usually has a ‘normalising’ effect on empty bowel  : it helps to prevent constipation whilst also counteracting the abnormal rapid transit times related to diarrhoea.

Another benefit of fibre is that it has an outstanding lowering effect on blood cholesterol levels.  The fibre binds to the bile acids that emulsify fats. Cholesterol is used by the liver to produce these bile acids. When the soluble fibre binds to the acids in the small intestine they are then removed from the system.  The liver then uses up more cholesterol to produce more acids and the process begins again and again. In that way, fibre is able to aid in reducing cholesterol levels in the body.  As fibre increases the rate at which bile is excreted it may also help in preventing the formation of gallstones.

The British Nutrition Foundation recommends a minimum daily fibre intake of 12-14g for healthy adults.  This is a low amount compared to the amount of fibre that our ancestors used to consume, humans evolved to ferment approximately 50-90g daily.  It is thought that the low amounts of fibre consumed daily and also the minimal diversity of the fruit and vegetables that we eat are a main factor contributing to the levels of obesity in developed countries.

By eating 25-40g of fibre daily you could help to reduce the risk of developing heart disease, diabetes, high blood pressure, colon cancer and other intestinal disorders.

Increasing your intake of fibre should be done gradually and you should ensure that you are drinking adequate amounts of fluid, between 1.5 – 2 litres daily.

As mentioned before there are two types of fibre – soluble and insoluble.  Most plants contain a combination of the two e.g. Plums have a thick skin covering a juicy pulp inside.  The skin is insoluble fibre and the pulp soluble fibre.

Soluble fibre, also known as fermentable fibre, is found in;

  • Pulses and legumes e.g. sesame and sunflower seeds, kidney beans, oats, barley and rye,
  • fruits such as apples and pears,
  • leafy vegetables such as broccoli and cabbage amongst others.

Soluble fibre is sticky and forms a gel in water causing food to be absorbed at a slower rate; it is a main influence in absorption within the stomach and the small intestine.  It delays food from leaving the stomach, and makes you fill fuller for longer, which can help to control weight.

As cooking can destroy most of the fibre in vegetables and fruits it is best to either eat them raw or cook them as lightly as possible which will ensure fibre remains intact.

Insoluble fibre does not dissolve in water and has only a partial or low fermentation when eaten, ensuring that it passes through the gut relatively intact.  Although insoluble fibre does not dissolve in water it can bind with it and take up large amounts holding onto the water which adds bulk to stools and makes waste pass through the digestive tract more quickly which is good for the gut and can help to prevent constipation.

Insoluble fibre can be found in (amongst others);

  • wholegrains – wholemeal breads and pastas, brown rice,
  • apples, green beans, kidney beans and broccoli,
  • nuts and seeds

To increase your dietary fibre intake you could;

  • include plenty of vegetables with your meals,
  • have a high fibre breakfast such as bran flakes or porridge,
  • choose wholegrain or granary breads instead of white,
  • add pulses such as chickpeas, beans or lentils to stews and curries or eat as side dishes,
  • eat nuts and seeds, rye crackers or oatcakes for snacks