Fiber in your Diet
What is fibre?
Fibre is the structural part of a plant that supports and holds it together. It is a carbohydrate and is referred to as non-starch polysaccharide (NSP) in scientific circles and ‘roughage’ in everyday language. Fibre can be chewed, swallowed and subjected to stomach acid, yet much of it passes through the body unchanged.
Why do we need fibre?
Dietary fibre acts like a sponge, absorbing water to increase the bulk and softness of stools. This ensures that they are eliminated easily from the body. If you increase your intake of fibre, it is also important that you increase your fluid intake.
Fibre is important because it:
- Stimulates the digestive tract and helps it work efficiently
- Encourages the presence of health-giving bacteria in the large intestine
- Softens the stool (bowel motion) and helps prevent constipation
- Slows down carbohydrate absorption, making meals more satisfying and therefore helping with weight management
Fibre has also been associated with a decreased incidence of certain cancers of the digestive tract.
Which foods contain fibre?
There are two major types of fibre – soluble and insoluble. Plant foods generally contain a combination of both types.
Food types which are predominantly high in soluble fibre are:
- Pulses (e.g. peas, beans)
Soluble fibre is broken down by enzyme-producing bacteria present in the colon to produce energy and gas and bulky stools. This fibre forms a gel-like substance which can bind to other substances in the gut. It also has the extra benefits of lowering cholesterol levels and slowing down the entry of glucose into the blood, thereby improving blood sugar control.
Foods predominantly high in insoluble fibre are:
- Fruit and vegetables with their skins and pips
- Wholegrain cereals (wheat, rye, rice)
- Nuts and some pulses
Insoluble fibre is less easily broken down by bacteria in the colon, but holds water very effectively (up to 15 times its weight in water) thus contributing to an increase in stool weight. It is this fibre that is often referred to as ‘nature’s broom’ and is thought to have many protective effects on the gut.
How much do we need?
Only the correct combination of these two types of fibre will ensure proper bowel function. Most of us need to increase both types of fibre in our diet. By following a healthy balanced diet this can be easily achieved. Gradually increase the amount of fibre you eat, as your digestive system will need time to adapt. If you introduce too much fibre into your diet too quickly, you may experience: bloating, constipation, excessive wind (flatulence), pain.
- Ensure that all the starch or grains you eat are the high fibre varieties. Read the labels of cereals and breads to confirm the fibre content. A high fibre cereal should contain at least 5gms total fibre per serving.
- Switch to wholegrain breads. (Should contain at least 2-3g of fibre per slice)
- Introduce more wholegrains such as wholemeal pasta and brown rice into your main meal.
- Have 3 servings of fruit and 2 of vegetables per day, where possible raw and with their skins, pips and membranes. Start the day off by including a piece of fresh fruit with your breakfast, have fruit as a dessert and as a snack between meals. Tinned, frozen and dried fruit and vegetables are also beneficial.
- Snack on high fibre healthy foods like dried fruit, nuts and raisins, wholemeal biscuits, rusks and popcorn.
- Try including beans, peas or lentils as part of your main meal.
- Try to cut down on processed, pre-prepared foods. They mostly have a lower fibre content than their fresh alternatives.
Don’t forget the fluid
Without fluid, dietary fibre cannot do its job. Insoluble fibre, in particular, acts like a sponge absorbing water, increasing stool weight and size, thus putting pressure on the bowel wall and facilitating the movement of the stool. Without fluid this fibre is pointless and will only result in constipation. Try to drink at least 3-4 pints (8-10 cups) of fluid per day. Suitable fluids include non-caffeine and non-alcohol based drinks like water, fruit teas, well-diluted fruit juices and fruit squashes.