Microbiota of The GI Tract

Question 1

Why are there differences in the bacterial communities throughout the GIT?

Answer 1

There are different bacterial communities along the GI tract, due to the variation in certain conditions along the GI tract:

1) pH variations
2) Oxygen concentration variations
3) Variation in transit times

Question 2

What are the activities of the different bacterial species?

Answer 2

1) Metabolism of dietary components
2) Produce essential metabolites
3) Development of immune system
4) Host signalling
5) Defence against pathogens
6) Modification of host secretions

Question 3

Why is the presence of/products of bacteria important for a healthy gut?

Answer 3

• Bacteria in the stomach can provide defence against pathogens (barrier effect and active competitive exclusion)
• Help develop immune system
• Produce essential metabolites to maintain health.
• Gut bacteria help metabolise dietary components such as fibre.

Question 4

What are the impacts of different diets on bacterial activity?

Answer 4

Damaging:

Heterocyclic amines

N-nitrosamines

Protective:

Phytoestrogens

Short Chain Fatty acids

Anti-oxidants