Carbohydrate digestion

Question 1

What is the function of proteins?

Answer 1

Energy source
protein sparing
prevent ketosis

Question 2

What are the two forms of carbohydrates?

Answer 2

Complex carbohydrates: Starch (potatoes and bread) and fibre (insoluble: bran, soluble: lentils, beans oatmeal)

Simple carbohydrates: Sugars- disaccharides (maltose, sucrose and lactose) + monosaccharides (glucose, galactose and fructose)

Question 3

Where would you find the disaccharides?

Answer 3

Sucrose: table sugar
Lactose: milk
Maltose: fermentation/alcohol production

Question 4

How are carbs digested to begin with?

Answer 4

In the mouth, amylase breaks down starch

Question 5

What happens in the stomach?

Answer 5

Stomach acid halts digestion as amylase becomes inactive.

Question 6

What happens in the small intestine?

Answer 6

Pancreatic amylase continues digestion, causing starch to maltose
Disacchardases also break down disaccharides:
Maltose –> Glucose + glucose
Lactose–> glucose + galactose
Sucrose–> glucose + fructose

Question 7

Where does carb absorption occur?

Answer 7

In the small intestine mainly, where glucose and lactose are absorbed by active transport, and fructose by facilitated diffusion

Question 8

What is the cause, what are the symptoms, and how can lactose intolerance be managed?

Answer 8

Caused by a lactase deficiency
Symptoms include abdominal discomfort, bloating and diarrhoea
Can be managed by not eating dairy products or enzyme treatment

Question 9

What role does dietary fibre play in our diets?

Answer 9

Maintains bowel health
Insoluble: softens stool; increases transit time
Soluble: Binds with fatty acids; regulates blood sugar; lowers cholesterol and LDL; fermented by bacteria