What is dietary fibre?
Dietary fibre, “bulk” or “roughage” (a complex carbohydrate) is the part of plant-derived foods that can’t be completely broken down by digestive enzymes in the human digestive system. Instead, it travels through the gut largely untouched, when it arrives in the colon where it may or may not be fermented by gut bacteria or micro flora. This is in direct contrast with most other nutrients, which are fully digested and used in other parts of the body during the digestive process.
Fibre is probably not something you think about too often, unless you suffer with chronic constipation or other symptoms of poor digestion on a regular basis. However, it plays a very important role in helping to maintain, not only a regular digestive system, but also a healthy body, for everyone.
As mentioned above, fibre is derived from plant sources, such as fruit, vegetables and grains, and contributes to digestive regularity, toxin elimination and is a key ingredient to a healthy, varied and balanced diet. Most people consume different types of fibre daily, without realising it. However, the quality of this fibre will vary greatly.
It is important to remember that fibre is about much more than just eating unprocessed bran, as is sometimes promoted by cereal companies. Bran has the potential to irritate many people’s guts, producing bloating, excessive wind and anal discomfort.
Soluble and insoluble fibre
Dietary fibre is often categorised according to its solubility, as soluble or insoluble fibre. In other words, whether it dissolves or not. Both types of fibre are found in different proportions in fibre foods.
What is soluble fibre?
Soluble fibre, essential for healthy digestion, is fibre that dissolves in water; a soft fibre that absorbs water as it moves through the digestive tract. It is made up of sticky substances like gums and pectin, which form a gel-like substance in the presence of liquid.
It is found in fruit, vegetables and other plant-based foods, and is probably best known for its cholesterol-lowering effects and ability to regulate blood sugar levels. When soluble fibre absorbs water, it turns into a gelatinous substance which is then fermented in the colon to produce short chain fatty acids. Soluble fibre is thought to bind with cholesterol and prevent it from being reabsorbed into the bloodstream. This helps to lower the amount of cholesterol in the blood, therefore reducing the risk of heart disease.
This type of fibre is a fermented source of nutrition, which means that it is acted upon by the normal bacteria in your intestines, which helps to break down the carbohydrates in your colon. One of the benefits is that your stomach stays fuller longer, providing a feeling of fullness.
Especially good sources of insoluble fibre include beans and other legumes, whole grains and certain fruit and vegetables (such as apples, citrus fruits and strawberries, and peas and lentils).
What is insoluble fibre?
Insoluble fibre, resistant to human digestive enzymes, is not digested by the body and it does not dissolve in water. It acts like a sponge, absorbing water and moving solid waste out of the intestines. In this way, it promotes regularity and softens stools
It is mainly found in wholegrain foods (such wheat bran, brown rice and couscous), root vegetables (such as carrots, parsnips and potatoes), celery, cucumbers and courgettes, fruit with edible seeds, beans, pulses and lentils, nuts and seeds.
Constipation is a serious and chronic problem for many people of all ages in today’s fast-paced, fast-food society. Stress, low-fibre diets, lack of exercise, certain medications, very little insoluble fibre in the diet and dehydration all often result in continuous bowel problems. Toxic bowel material needs to be passed every day. Otherwise, if allowed to build up in the colon, it can lead to a range of bowel disorders and diseases.
Ironically, constipation can be a side-effect of a high-fibre diet if fluid intake isn’t also increased. This is because fibre acts like a sponge and absorbs water.
Why is fibre good for you?
Diets that are high in fibre have been shown to be beneficial in a number of ways, from supporting digestive health and regularity, to helping to eliminate toxins from the body. High fibre diets also help to regulate blood sugar levels, lower cholesterol levels and keep you feeling fuller for longer, thereby also supporting natural weight loss and a healthy heart.
Your daily diet should ideally contain between 25 – 30 grams of high quality fibre.
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