Carbohydrates

Question 1

Function for carbohydrates

Answer 1

To supply the body with energy

Question 2

How much energy is in 1g of pure starch or sugar?

Answer 2

3.75 kcal

Question 3

Name the three types of carbohydrates

Answer 3

Starchy carbohydrates
Sugary carbohydrates
Non starch polysaccharide (NSP or fibre)

Question 4

Explain how starch provides us with energy

Answer 4

It’s formed from thousands of glucose units joined together, so when starch is digested, the big molecule is gradually broken down into smaller pieces and as this happens energy is released.

Question 5

Sources of starch

Answer 5

Potatoes
Bread
Rice
Pasta
Breakfast cereals
Cous cous, quinoa

Question 6

Explain how sugar provides energy

Answer 6

It’s a small molecule that can be digested quickly - provides an immediate, but short-lived, supply of energy.

Question 7

Examples of sugary foods

Answer 7

Sweets
Cakes/buns
Biscuits
Chocolate
Fizzy drinks
Fruit juices
Jam/marmalade 
Ice cream

Question 8

Adults are advised to have an intake of …g of NSP (fibre) per day.

Answer 8

18g

Question 9

Sources of insoluble NSP

Answer 9

Wholegrain: - breakfast cereals
                      - bread
                      - (brown) pasta
                      - (brown) rice
Nuts
Pulses (peas, beans, lentils)

Question 10

Function of insoluble NSP

Answer 10

Acts like a sponge and absorbs water to add bulk to the faeces, making it soft and easily removed from the body.

Question 11

Benefits of insoluble NSP

Answer 11

Reduces the risk of constipation, diverticular disease & bowel cancer.

Question 12

Explain the process of constipation

Answer 12

The faeces become very hard and move slowly through the intestine - a lot of effort is required to move them. It can result in abdominal discomfort and a general feeling of ill health.

Question 13

Explain diverticular disease

Answer 13

May develop if the faeces are small and hard (due to lack of NSP and insufficient water). The muscular walls of the intestine have to work harder to move them along, causing increased pressure, leading to pouches of the bowel lining being forced out through the intestine wall. If the pouches (diverticula) become inflamed, it’ll cause discomfort.

Question 14

Sources of soluble NSP

Answer 14

Oats
Pulses (peas, beans, lentils)
Fruit
Vegetables

Question 15

Function of soluble NSP

Answer 15

Helps to reduce blood cholesterol levels & therefore helps to reduce the risk of coronary heart disease.

Question 16

Eating too many sugary & starchy carbohydrates may increase your risk of developing obesity. Why?

Answer 16

Excess energy is stored in the body as fat (adipose tissue).

Question 17

Obesity can increase your risk of developing other health problems later in life, for example…

Answer 17

CHD
Type 2 diabetes
Some cancers
Hypertension (high blood pressure)

Question 18

Why should most of your energy intake come from starchy carbohydrates?

Answer 18

They provide a steady release of energy, which lasts longer, whereas sugar only provides a ‘quick’ release of energy

Question 19

Eating too many sugary carbohydrates can increase your risk of developing ….….………… . How?

Answer 19

Tooth decay. Bacteria in your mouth feed on which produces an acid. The sticky mixture of food, bacteria and acid is called plaque. The acid erodes at the tooth enamel, eventually causing tooth decay.

Question 20

What substance do fizzy drinks contain that also dissolves tooth enamel?

Answer 20

Phosphoric acid

Question 21

State the equation for the erosion of tooth enamel.

Answer 21

Sugar + bacteria -> acid

Question 22

List ways in which parents can help reduce the risk of their children developing tooth decay

Answer 22

(i) Limit consumption of sugary foods and drinks between meals
(ii) Replace fizzy drinks with milk or water
(iii) Encourage to brush teeth at least twice a day with fluoride toothpaste
(iv) Bring to regular dental check-ups, at least twice a year

Question 23

Effects of a deficiency of carbohydrates

Answer 23

[It’s very unlikely for a person to have a deficiency in carbohydrate]
Lack of energy, lethargy (tiredness), weight loss.