The gut microbiota in health and disease

Question 1

List some factors that affect gut microbiota

Answer 1

• Environment
• Probiotics
• Antibiotics
• Prebiotics
• Faecal transplant
• Disease
• Diet
• Lifestage

Question 2

What can be seen in the microbiota of those with IBD?

Answer 2

Reduced biodiversity - reduction in Firmicutes (Gram +ves) and an increase in facultative anaerobes like E. coli and other Enterobacteriaceae

Question 3

What features of IBD could cause a change in microbiota?

Answer 3

• Antibiotic use
• Inflammation
• Diarrhoea
• Host diet
• Host genotype

Question 4

What is a probiotic?

Answer 4

Probiotics are live organisms which, when administered in adequate amounts, confer a health benefit on the host

Question 5

What is a prebiotic?

Answer 5

Prebiotic is a selectively fermented food/ingredient that results in specific changes in the composition and/or activity of the GI microbiota, thus conferring benefit on the host health. These can be found naturally in some plant food, while also added to cereals, biscuits, breads, drinks and yoghurts

Question 6

What is a symbiotic?

Answer 6

Synbiotics are mixtures of probiotics and prebiotics that beneficially affect the host by improving the survival and implantation of live microbial dietary supplements in the gastrointestinal tract

Question 7

Describe a low FODMAP diet

Answer 7

[FODMAP – fermentable oligosaccharides, disaccharides, monosaccharides and polyols)
Diet designed to reduce bacterial fermentation; identifies key foods to exclude permanently, though diet is only for a limited period to allow survival of microbiota

Question 8

What are the mechanisms of action of probiotics?

Answer 8

1. Competition
2. Bioconversions (diet)
3. Production of vitamins
4. Direct antagonism (pathogens)
5. Competitive exclusion
6. Barrier function
7. Reduce inflammation
8. Immune stimulation

Question 9

What is a common result following broad spectrum antibiotic use?

Answer 9

CDAD - C. difficile associated diarrhoea

Question 10

How is CDAD treated?

Answer 10

Antibiotics

If doesn’t work, foetal microbial transplantation

Question 11

What diseases have been linked to changes in gut microbiota?

Answer 11

• Irritable bowel syndrome
• Inflammatory bowel disease
• Cardiovascular disease
• Allergies
• Obesity
• Bone health
• Brain health
• Rheumatoid arthritis
• Diabetes
• Colorectal cancer