Microbiome (GIT)

Question 1

What is the relationship between plant polysaccharide intake and intestinal microbiota?

Answer 1

Most complex plant polysaccharides aren’t digested by humans and enter the colon as a food source for microbiota.

E.g. Japanese people have microbiota that can harvest energy from seaweed - NA people don’t.

Question 2

What is dysbiosis and what can cause it?

Answer 2

Dysbiosis is an imbalance in the microbial community, associated with disease.

It can be caused by overgrowth of members of commensal bacterial (e.g. enterobactericeae in irritable bowel syndrome) or by loss of commensals (e.g. in antibiotic therapy, accompanied by overgrowth of pathogens)

Question 3

Microbiota diversity can be measured - what is meant by alpha and beta diversity?

Answer 3

Alpha diversity = how many different species are present.

Beta diversity = measure of diversity between two samples (e.g. Sample X and Y have large beta diversity, as they have very few organisms in common)

Question 4

What are the positive and negative effects of the gut microbiome?

Answer 4

Positive

• Role in digestion, nutrient supply
• Protection and clearance from pathogenic invasion

Negative

• Gastrointestinal disorders
• Colon cancer development
• Metabolic syndromes such as diabetes, obesity

Question 5

What is the relationship between a diet low in animal fat and protein, but high in plant fibres vs diet high in animal fat and protein and low in plant fibres on gut microbiota?

Answer 5

Plant fibres are broken down into food sources that promote development of microbiota related to metabolic health.

Animal fats and proteins are broken down into compounds that promote development of microbiota related to metabolic diseases.

Good microbiota are though to decrease blood glucose and increase energy expenditure. Bad do the opposite.

Question 6

What are short chain fatty acids, and why are they beneficial?

Answer 6

Short chain fatty acids come from breakdown of indigestable plant polysaccharides.

SCFAs are though to have many health benefits.

Question 7

What is the hygiene hypothesis?

Answer 7

Early life exposure to commensals, rather than pathogens is though to protect from allergic disease.

Question 8

What are some factors related to microbiota modulation from pre-natal to post-natal?

Answer 8

Placenta

Breast milk feeding

Family members

Maternal diet

Question 9

What are the most abundant microorganisms in the gut?

Answer 9

Archaea.

Thought to play a role in periodontal disease.

Question 10

What are some interventions to improve gut microbiome?

Answer 10

Exercise

Nutrition

Faecal microbiota transplantation

Prebiotics, probiotics.