Fibre

 

What is fibre?

Fibre is a kind of carbohydrate that helps your digestive system work well by making food move through it. Fibre is also called roughage or Non-Starch Polysaccharide (NSP).

We can get fibre from different foods like vegetables and fruits such as carrots, potatoes, beans, broccoli and peas, apples, raspberries, strawberries, bananas, plums and prunes. We can also get fibre from seeds, lentils, nuts and beans and whole grain foods like wholemeal flour, bread, pasta and rice. Fibre is very important for our health. If we don’t eat enough fibre, we might get constipated and have other serious health problems such as cancer in the bowel and colon and high blood pressure and heart disease.

 

How much fibre do we need?

Different ages need different amounts of fibre. For example, 11-16 year olds should eat about 25 grams of fibre every day. A diet with a lot of fibre can help you feel less hungry and more satisfied for longer. The right amount of dietary fibre can stop constipation and lower the chance of heart disease, stroke, type 2 diabetes, bowel cancer and obesity.

 

Soluble vs. insoluble fibre

There are two kinds of fibre in foods that have a lot of fibre: soluble and insoluble fibre. Soluble fibre can dissolve in water and turns into a gel-like substance in the large intestine. It can help lower blood cholesterol. You can find this fibre in foods like chickpeas and carrots. Insoluble fibre does not dissolve in water. It goes through the digestive tract and takes in fluid and other waste matter. The fibre helps the waste matter move through the intestines and out of the body. This kind of fibre can help stop constipation. You can find this fibre in foods like rice and nuts.

 

🍎 Knowledge Check: Fibre & Digestion

Test your understanding of why "roughage" is vital for your health.

1. Which carbohydrate is the main component of dietary fibre?

• Starch
• Cellulose
• Glucose

2. Fibre is not considered a 'nutrient' in the traditional sense because:

• It contains no atoms.
• It is poisonous to humans.
• It cannot be digested or absorbed into the blood.

3. How does fibre help prevent constipation?

• By providing bulk for the digestive muscles to push against.
• By dissolving into a liquid in the stomach.
• By killing bacteria in the large intestine.

4. What is the name of the wave-like muscle contractions that move food through the gut?

• Diffusion
• Peristalsis
• Active Transport

5. Which of these meals would provide the MOST dietary fibre?

• Grilled chicken and white rice
• A plain omelette with cheese
• A jacket potato with the skin on and baked beans

Click to Reveal Answers

1. Cellulose (Found in plant cell walls).
2. Cannot be absorbed (It leaves the body the same way it entered!).
3. Providing bulk (This keeps the muscles of the intestine active).
4. Peristalsis (Key biological process for KS3 Biology).
5. Jacket potato with skin and beans (Plant skins and legumes are excellent fibre sources).

 

Summary:

 

• Dietary fibre is plant material that your body can’t break down.
• Dietary fibre helps your digestive system to move food along the intestines and get rid of the waste material.
• Foods that have a lot of fibre are beans, pulses, and vegetables like broccoli and carrots.