The fibre in our diet comes from plant cell walls and can be divided into two main types of fibre, soluble and insoluble.

Understanding the different types of fibre makes it easier to incorporate them into your diet in the best way.  As many fibre-rich foods have additional benefits, it should be easy enough to choose the best way for you to get the right amount or fibre into your diet.

Why do I need fibre in my diet?

Dietary fibre contributes to a good, healthy gut and some fibres have other benefits such as balancing blood sugar levels and reducing blood cholesterol levels.

Fibre helps create a feeling of fullness which helps with dieting and soluble fibre can help with mood swings.

How much fibre should I eat?

Adults should eat between 18gm – 30gm of fibre per day, of which one third should be soluble and two thirds insoluble.

Many foods which are naturally high in fibre contain both soluble and insoluble fibre.

You should increase the levels of fibre in your diet slowly and drink extra water to avoid wind of bloating.

Insoluble fibre

These are the original ‘roughage’ type fibres consisting of the tougher parts of the plant material that are made of cellulose, hemicellulose and lignin.  This is the material that builds the stems of plants as well as the outer husk of seeds, grains and pulses.

Natural sources of insoluble fibre

Good sources of insoluble fibre include pulses such as beans and lentils; whole grain, wholemeal and bran from cereal grains and fruits with edible seeds.

The benefits of insoluble fibre

The role of insoluble fibre in the diet is to stimulate the movement of food through the digestive tract, a process known as peristalsis.  Some insoluble fibres have other health benefits, for example the lignified fibre in linseeds contains phytoestrogens, plant derived oestrogens which help women with their hormone balance.

How insoluble fibre works

Insoluble fibre is not broken down by bacteria in the gut, instead it absorbs water and speeds up digestive transit time.  This reduces both the work the colon has to do and the risk of bowel disease such as piles, diverticulosis, IBS (Irritable Bowel Syndrome) and colon cancer.

Soluble fibre

Where the scientific benefits of ‘roughage’ have been known for centuries, the understanding the role of soluble dietary fibre is more recent.

Natural sources of soluble fibre

Soluble fibre is found in the gums, mucilages and pectins of the plant world.  It is found in fruit, especially citrus fruit, and seeds such as flax.  Barley. oats, maize, apples, bananas and strawberries are also good sources but most legumes, fruits and root vegetables contain soluble fibre.  Novel food sources include Nopal cactus and Yacon

The benefits of soluble fibre

Soluble fibre is known not only for its benefits on the digestive tract, but also for slowing down the release of sugar into the bloodstream and lowering cholesterol levels in the blood.  It also acts as a food for the good bacteria in the gut.

How soluble fibre works

Soluble fibre is broken down or ‘degraded’ by enzymes in the gut which are produced by the good or friendly bacteria.  The fibre mixes with water to produce a gel-like fibre which keeps food in the stomach for longer before it empties, this releases energy into the bloodstream more slowly and has a beneficial effect on blood sugar levels.

In addition, some soluble fibres bind with the fat-emulsifying acids from the bile gut.  This combination increases the excretion of these fats which would otherwise be deposited as arterial plaque.

FOS – Fructo Oligo Saccharides

FOS are a specific group of insoluble fibre which are particularly good at supporting the growth of beneficial bifidus bacteria in the gut.  They are naturally sweet but have no calorific value.

Natural sources of FOS

Commercial FOS are extracted from chicory root, but good food sources include the allium family; garlic, onions and leeks; Jerusalem artichokes, bananas, wheat and dandelion leaves.

The benefits of FOS and how they work

FructoOligoSaccharides are also known as pre-biotics, that means they provide a good growing medium for friendly bacteria known as pro-biotics.  This synergistic relationship between the two, alters the pH of the colon in favour of the good bacteria and helping to exclude the bad (pathogenic) or disease causing bacteria.