Gut Microbiome (HL)

What is the microbiome?

A collection of genomes from all microorganisms living in a specific environment.

What is microbiota?

Microorganisms such as bacteria, viruses, fungi and parasites found in a specific environment (e.g. the gut).

What are the two main roles of the gut microbiome?

Extracting and synthesising nutrients from food and providing defence against pathogens.

How does the gut microbiome protect the body?

Prevents pathogen overgrowth, inhibits harmful bacteria and interacts with the immune system.

How does the gut influence the brain?

The gut secretes neurotransmitters that influence mood regulation and cognition.

Where are most nutrients absorbed in the digestive system?

The small intestine.

What happens to nutrients that are not absorbed in the small intestine?

They move to the large intestine where microorganisms break them down.

What signals does the gut send to the brain?

Signals indicating hunger when empty, fullness when full, and warnings when harmful pathogens are present.

What is the gut-brain axis?

A two-way communication system between the gut, brain and spinal cord.

What functions are influenced by the gut-brain axis?

Mood, cognition and mental health.

Why is maintaining a strong gut barrier important?

It prevents bacteria from passing through the gut wall into the bloodstream.

What can happen if gut wall permeability increases?

Bacteria may move into the bloodstream, increasing infection risk and inflammation.

What dietary factors influence the gut microbiome?

Dietary fibre, fermented foods and polyphenols.

What lifestyle factors influence the gut microbiome?

Physical activity, sleep, stress, smoking and alcohol consumption.

What other factors influence the gut microbiome?

Genetics and medications such as probiotics and antibiotics.

What is the role of dietary fibre in gut health?

Acts as a food source for beneficial gut bacteria and promotes healthy digestion.

What are polyphenols and how do they affect gut health?

Plant compounds that promote beneficial bacteria growth, inhibit harmful bacteria and reduce inflammation.

How do fermented foods improve gut health?

They contain probiotics that introduce beneficial bacteria into the gut.

What are antibiotics?

Medications that destroy bacteria, including both harmful and beneficial bacteria.

How can antibiotics affect the gut microbiome?

They can cause gut dysbiosis by disrupting microbial balance.

What are probiotics?

Live beneficial bacteria that support gut health and help restore microbial balance.

How do probiotics improve digestion?

They enhance food breakdown and improve nutrient absorption.

How can probiotics reduce gastrointestinal disorders?

They help manage conditions such as diarrhoea, IBS and inflammatory bowel disease.

How can probiotics influence metabolic health?

They regulate metabolism, improve insulin sensitivity and reduce obesity-related risks.

What is Relative Energy Deficiency in Sport (RED-S)?

A condition caused by an imbalance between energy intake and energy expenditure, commonly seen in athletes with high training loads.

How can RED-S cause gastrointestinal complaints?

Low energy availability reduces blood flow to the gut, impairing digestion and nutrient absorption.

How does RED-S affect gut motility?

Chronic energy deficiency may slow digestion and cause irregular bowel movements.

How does RED-S affect gut barrier function?

It can increase intestinal permeability, leading to inflammation and GI discomfort.

How does RED-S affect gut microbiome diversity?

Reduced nutrient intake lowers microbiome diversity and beneficial bacteria growth.

How does RED-S affect metabolite production in the gut?

Energy deficiency reduces production of short-chain fatty acids that support gut health.

How can athletes mitigate the effects of RED-S on gut health?

Ensure adequate energy intake, consume probiotics and fibre, maintain hydration, and manage training load and recovery.