7.7 Non-digetsible Food Components

Question 1

What are the components of the large intestine

Answer 1

cecum, colon, rectum and anus

Question 2

What are the different sections of the colon

Answer 2

the ascending colon, transverse colon, descending colon and sigmoid colon

Question 3

What is the main fermentation chamber in the large intestine

Answer 3

The ascending colon due to its high bacteria population

Question 4

What are some functions of the large intestine

Answer 4

-colonic bacterial metabolic activity, fermenting carbohydrates to produce short chain fatty acids

-vitamin K absorption

-absorption of water and electrolytes from colonic contents to form solid faeces

-storage of faecal matter

-prevention of establishment of pathogenic bacteria

Question 5

Describe the different sub categories of dietary fibre

Answer 5

Dietary fibre can be soluble or insoluble.

Soluble fibres can form viscous solutions or they can be fermented by bacteria to produce short chain fatty acids

Question 6

What is the benefit of fermentable fibre

Answer 6

The soluble fibre can be fermented by bacteria to produce metabolites such as short chain fatty acids. Different SCFAs have different health benefits such as acting reducing cholesterol synthesis, stimulating gut cell proliferation, reducing the gut pH and synthesising glucose.

Question 7

What are some short chain fatty acids

Answer 7

Acetic acid, propionic acid, butyric acid

Question 8

What is the effect of fibre on gut transit time

Answer 8

In the stomach and small intestine, soluble fibre reduces gastric emptying.

In the colon, insoluble fibre increases propulsion via peristalsis

Question 9

What are some advantages of a high fibre diet

Answer 9

-slower absorption of nutrients so increased satiety and lower glycaemic response
-lower plasma cholesterol
-increased stool output
-SCFA in colon lowering colonic pH