NTP Gut Health & Microbiome 2 — Questions and Answers
Question 1: Which short-chain fatty acid (SCFA) is the primary energy source for colonocytes?
- Acetate
- Propionate
- Butyrate (Correct answer)
- Lactate
Correct answer: Butyrate
Butyrate is the preferred fuel for colonocytes and plays a key role in maintaining intestinal barrier integrity.
Question 2: Secretory IgA (sIgA) in the gut primarily functions to:
- Trigger systemic inflammation
- Neutralize pathogens and prevent microbial adhesion to epithelium (Correct answer)
- Stimulate gastric acid secretion
- Break down dietary proteins
Correct answer: Neutralize pathogens and prevent microbial adhesion to epithelium
sIgA is the dominant antibody in mucosal immunity, binding pathogens and toxins to prevent them from adhering to intestinal epithelial cells.
Question 3: A client presents with bloating that worsens with high-FODMAP foods. The NTP would most likely suspect dysregulation in:
- Pancreatic enzyme secretion
- Small intestinal bacterial overgrowth (SIBO) or carbohydrate malabsorption (Correct answer)
- Bile acid recycling
- Gastric emptying rate
Correct answer: Small intestinal bacterial overgrowth (SIBO) or carbohydrate malabsorption
FODMAPs are fermentable carbohydrates; excessive fermentation by bacteria, as in SIBO, produces gas and bloating.
Question 4: Which of the following best describes the 'leaky gut' mechanism?
- Hypersecretion of mucus reducing nutrient absorption
- Increased intestinal permeability due to tight junction dysfunction (Correct answer)
- Reduced peristalsis causing constipation
- Overproduction of digestive enzymes damaging villi
Correct answer: Increased intestinal permeability due to tight junction dysfunction
Leaky gut (intestinal hyperpermeability) occurs when tight junction proteins loosen, allowing undigested particles and pathogens into the bloodstream.
Question 5: Which bacterial phyla ratio is commonly used as a marker of gut microbiome balance?
- Lactobacillus to Bifidobacterium
- Firmicutes to Bacteroidetes (Correct answer)
- Akkermansia to Faecalibacterium
- Prevotella to Ruminococcus
Correct answer: Firmicutes to Bacteroidetes
An elevated Firmicutes-to-Bacteroidetes ratio has been associated with obesity and metabolic dysfunction in numerous studies.
Question 6: Akkermansia muciniphila is considered a beneficial gut bacterium primarily because it:
- Produces vitamin K2
- Degrades and reinforces the mucus layer, supporting gut barrier integrity (Correct answer)
- Synthesizes all essential amino acids
- Directly neutralizes LPS endotoxin
Correct answer: Degrades and reinforces the mucus layer, supporting gut barrier integrity
Akkermansia muciniphila colonizes the mucus layer and is associated with improved gut barrier function and reduced metabolic endotoxemia.
Question 7: In the context of the gut-brain axis, which vagal signaling pathway carries information from enteroendocrine cells to the brain?
- Sympathetic afferent fibers
- Somatic motor neurons
- Vagal afferent fibers (Correct answer)
- Spinal sensory neurons only
Correct answer: Vagal afferent fibers
Vagal afferent fibers transmit signals from enteroendocrine cells and gut microbiota metabolites to the central nervous system via the gut-brain axis.
NTP Gut Health & Microbiome 2
Which short-chain fatty acid (SCFA) is the primary energy source for colonocytes?