There are two types of fibre:

1. Insoluble fibre gives a coarse texture to foods. It is found in wholegrains and cereals, bran, potatoes, and the skins of fruits and vegetables. This type of fibre doesn't dissolve in water.

2. Soluble fibre gives food a gel-like consistency and is found in fruits, vegetables, oats, barley, beans, legumes, pulses, and pectin. This type of fibre dissolves in water.

Health benefits

High-fibre food stops you from snacking. Fibre-rich food fills you up for longer, so you are less likely to snack on fatty and sugary foods between meals.

Fibre also keeps your gut healthy. Insoluble fibre has the ability to absorb or hold on to water, making the contents of your gut soft and moist, and so helping to prevent constipation.

Fibre reduces the likelihood of developing colon cancer. Insoluble fibres have the ability to hold on to or dilute substances that can cause cancer.

Slow moving food waste allows more time for cancer-causing compounds to come into contact with the walls of the intestines. By eating more fibre, you reduce the time it takes for waste to pass through the gut.

Soluble fibre can help lower blood cholesterol by trapping fatty substances in the intestines so the body doesn't absorb them.

Fibre helps people with diabetes control their sugar levels in the blood by slowing down the digestion of carbohydrates.

How much fibre?

Most health organisations suggest that adults should eat between 20-35g fibre a day.

However, Asians eat much less than this. A survey conducted in Singapore in 1983 showed that most adults ate only 15g a day.

Hong Kong people eat even less - a 1995 study showed that intake was less than 10g a day.

A 2005 survey conducted among kindergarten children in Hong Kong found that 30 per cent of the 561 children interviewed were constipated.

The American Dietetic Association uses a formula to work out how much fibre you need: Age in years + 5.

For example, a 13-year-old needs 18g of fibre a day (13+5).

Embarrassing gas

Sometimes, people who eat a high-fibre diet complain of flatulence, or 'gas'. As we don't have the enzymes to break down fibre, the fibre is fermented by bacteria which live in our colon.

A by-product of fermentation is gas.

You can prevent this by drinking more water; soaking dried beans in water before cooking and cooking them for longer than the recommended time; and slowly introducing more fibre into your diet if you are used to a low-fibre diet.

Label know-how

The American Dietetic Association uses these guidelines to determine the level of fibre in food: 5g or more per serving means food is high fibre; 2.5-4.9g per serving means food is a good source of fibre; and 2.5g per serving means food is an average source of fibre.

Quiz

1. Name the two types of fibre

2. Fibre used to be known as . . .

a. ruffian

b. bran

c. roughage

3. Which of the following formulas helps you find out how much fibre children and teens need per day?

a. age in years + 10

b. age in years + 5

c. age in years + 2

4. Which of the following foods contains the most fibre per serving?

a. one medium-sized orange

b. one glass of apple juice

c. one slice of wholewheat bread

5. One medium-sized baked potato contains 2.9g fibre. This is a . . .

a. high source of fibre

b. good source of fibre

c. poor source of fibre

Answers:

1. insoluble and soluble fibre; 2.c; 3.b; 4.a; 5.b