News

29/09/2014

http://www.studenthealth.gov.hk/english/health/health_dn/health_dn_dfayb.html

Diet & Nutrition
Dietary Fibre and Your Body
Dietary fibre, or fibre, is the part of food that cannot be digested by our bodies. Therefore, there is a misconception that fibre is just food remains, while in fact, both water-soluble and water-insoluble fibre, found in different types of food, serve different functions in the body.
The health benefits of dietary fibre
Intake of adequate amount of foods with a high fibre content helps in the prevention of diseases and chronic body imbalances.
Prevention and relief of constipation
Fibre increases the bulk of stool and stimulates motion of the large intestine. It absorbs water, lubricates the large intestine and makes defecation easier.
Digestion and absorption
Fibre stimulates the secretion of digestive fluids and the action of "good" bacteria in the intestine, hence, stimulating the formation of vitamin B2.
Protection against cancer of the large intestine
Fibre prevents the accumulation of cancer-causing (or carcinogenic) materials because it shortens the retention period of waste materials.
Weight-control
As fibre absorbs large amount of water, it expands in volume and gives a sensation of fullness. Moreover, more time is required for chewing high-fibre foods, hence less food would be consumed.
Stabilization of blood sugar level and control of diabetes
Fibre can slow down the body's absorption of sugar.
Lowering of blood cholesterol level, hence prevention of heart disease
Water-soluble fibre combines with cholesterol and then excretes it.
Essential facts

• There is no fibre in fish, meat, shrimps, eggs and milk.
• Only foods of plant origin contain fibre. Examples include: Fungi - straw mushroom, button mushroom, white fungus, black fungus,
• Obtain fibre from food rather than fibre tablets, powder or other supplements.
• Consume differenttypes of fibre-rich foods because fibre from different food serve different functions.
• Increase fibre intake gradually to avoid gastrointestinal upset from sudden intake of large amounts of fibre.
• Too much fibre would lead to malnutrition and decreased absorption of minerals.
• Take fruits and vegetables together with the skin, like unpeeled plums, grapes.
• Fresh fruit is better than fruit juice because most of the fibre in fruit is damaged when it is squeezed to make juice.
• Fibre absorbs a lot of water. For fibre to function effectively, a daily intake of 6-8 glasses of fluid is required.
• Although fibre is important to health, we should not neglect other food types. A balanced diet and regular exercise are of utmost importance to good health.

 
Daily fibre requirement
Adolescence and adults need 25 g or above of fibre everyday while children need less. Add 5 to a child's age to calculate the amount of fibre needed per day (Age + 5 = grams of fibre required per day).
For example, a 6-year-old child would need 11g of dietary fibre per day.
Fibre content in different types of food

FOOD	Fiber (g) /100 g of Food	FOOD	Fiber (g) /100 g of Food
Cereals
White rice (uncooked)	0.6	Wholemeal cereals	11.7
White rice (cooked)	0.2	Cornflakes	3.6
Brown rice (uncooked)	3.4	Oatmeal (uncooked)	10.1
Brown rice (cooked)	1.8	Oatmeal (cooked)	1.7
Wholemeal bread	6.8
Fruits/dried fruits
Apple (with skin)	2.4	Raisin (seedless)	3.7
Orange (peeled and seedless)	2.4	Fig	2.9
Banana (peeled)	2.6	Dates (seedless)	6.7
Dried prune (seedless)	7.1	Dried Apricot	7.7
Vegetables
Broccoli (cooked)	3.3	Carrot (cooked)	3
Kale (cooked)	2	Corn (cooked)	2.4
Watercress (cooked)	1.2	Green pea (cooked)	5.5
Lettuce (raw)	1.5	Potatoes (baked, with skin)	2.2
Onion (raw)	1.7	Sweet potato (baked, with skin)	3.3
Tomato (raw)	1.2
Dried beans
Black-eye bean (cooked)	6.5	Mung bean (cooked)	7.6
Soya bean (cooked)	6	Kidney bean (cooked)	6.4
Red bean (cooked)	7.3
Others
Cashew nut	3.3	Sesame	11.8
Peanut	8.5	Chestnut (peeled)	1.2

Source： Central Health Education Unit of Department of Health
An example of a high-fibre diet

Meal	Food Type & Amount	Fiber (g)	Food Type & Amount	Fibre (g)
Breakfast	Low-fat milk, 1 glass (240ml)	0	Egg, 1 piece (50g)	0
	Whole meal bread, 2 slices (56g)	3.8
Morning Tea	Raisins, 1/2 cup (49g)	1.8	Whole meal crackers, 3 pcs (24g)	1.9
Lunch	Brown rice, 1 bowl (195g)	3.5	Broccoli (cooked), 1/2bowl (90g)	3.0
	Steamed fish (120g)	0	Banana, 1 piece (118g)	3
Afternoon Tea	Boiled corn 1/2 bowl ( 82g)	2.0
Dinner	Brown rice, 1 bowl ( 195g)	3.5	Meat or chicken (120g)	0
	Kale (cooked), 1/2 bowl (65g)	1.3	Orange,1 piece (131g)	3.1
Total fibre content				26.9

References : Nutrient Information Inquiry System, Centre For Food Safety
 
Thanks to Department of Health, Centre for Food Safety 
(Extracted from web page “Diet & Nutrition” of Student Health Service – Department of Health  )