Question 1

Which of the following best describes the difference between the terms 'microbiome' and 'microbiota' as used in gut health research?

Accepted Answer

Microbiome refers to the collective genomes of the micro-organisms in a particular environment, while microbiota refers to the community of micro-organisms themselves.

Question 2

A patient with type 2 diabetes is advised to increase their dietary fibre intake. Which of the following mechanisms best explains how increased fibre can improve their insulin sensitivity?

Accepted Answer

Increased fibre intake promotes the growth of gut bacteria that produce short chain fatty acids, such as butyrate, which improve glucose and energy homeostasis.

Question 3

Which of the following statements about short chain fatty acids (SCFAs) is CORRECT?

Accepted Answer

Butyrate is the main energy source for colonocytes and helps maintain gut oxygen balance, preventing dysbiosis.

Question 4

A researcher is studying the impact of antibiotics on gut microbiota. Which of the following findings is most consistent with current evidence?

Accepted Answer

Antibiotics can cause a reduction in gut microbiota diversity, which may promote weight gain and metabolic disturbances.

Question 5

Which of the following best explains why a low fibre Western diet is associated with increased risk of chronic diseases?

Accepted Answer

Low fibre intake reduces SCFA production, degrades the colonic mucus barrier, and increases susceptibility to pathogens and inflammation.

Question 6

A clinical trial finds that faecal microbiota transplantation (FMT) from lean donors improves insulin sensitivity in recipients with metabolic syndrome. What is the most likely mechanism for this effect?

Accepted Answer

FMT alters the recipient's gut microbiota composition, increasing beneficial metabolites such as butyrate, which improve insulin sensitivity.

Question 7

Which of the following dietary interventions is most likely to result in a temporary reduction in gut microbiota diversity, according to recent interventional studies?

Accepted Answer

A major increase in dietary fibre intake, which enriches specific fibre-digesting microbes.

Question 8

Which of the following is a plausible explanation for the observed association between low gut microbiota diversity and increased risk of diseases such as obesity, type 2 diabetes, and inflammatory bowel disease?

Accepted Answer

A species-rich gut ecosystem is more robust against environmental influences, allowing functional compensation when some species are lost.

Question 9

A patient with irritable bowel syndrome (IBS) is placed on a low FODMAP diet. Which of the following changes in their gut microbiota is most likely to occur?

Accepted Answer

A reduction in the proportion of Bifidobacterium species.

Question 10

Which of the following best describes the role of butyrate in the colon?

Accepted Answer

Butyrate serves as the main energy source for colonocytes and helps maintain hypoxia, which prevents dysbiosis.

Question 11

A nutritionist is designing a study to measure the functional capacity of the gut microbiota. Which of the following methods would provide the most comprehensive information about both composition and function?

Accepted Answer

Whole genome shotgun sequencing of microbial DNA.

Question 12

Which of the following statements about probiotics is supported by systematic reviews of randomised controlled trials?

Accepted Answer

Probiotic supplementation can reduce the incidence of antibiotic-associated diarrhoea in children.

Question 13

Which of the following is a key difference between prebiotics and probiotics?

Accepted Answer

Prebiotics are substrates selectively used by host micro-organisms, while probiotics are live micro-organisms administered for health benefit.

Question 14

A patient consumes large amounts of processed foods containing emulsifiers such as carboxymethylcellulose and polysorbate-80. What is the most likely effect on their gut microbiota?

Accepted Answer

Reduced microbial diversity and increased abundance of inflammation-promoting Proteobacteria.

Question 15

Which of the following best explains the relationship between dietary fibre, microbiota accessible carbohydrates, and prebiotics?

Accepted Answer

All prebiotics are microbiota accessible carbohydrates or fermentable dietary fibre, but not all dietary fibre is considered a prebiotic.

Question 16

A study finds that individuals with higher levels of the genus Christensenella in their gut microbiota are less likely to be obese. Which of the following experimental findings supports a causal role for this microbe in weight regulation?

Accepted Answer

Germ-free mice given Christensenella from lean humans gain less weight than those given microbes from obese humans.

Question 17

Which of the following equations correctly represents the calculation of the Homeostasis Model Assessment of Insulin Resistance (HOMA-IR), as used in studies of probiotic effects on type 2 diabetes?

Accepted Answer

$$	ext{HOMA-IR} = \frac{	ext{Fasting\,Insulin\,(\mu U/mL)} 	imes 	ext{Fasting\,Glucose\,(mmol/L)}}{22.5}$$

Question 18

A patient switches from a Western diet to a rural African diet high in fibre for two weeks. Which of the following changes in gut microbiota and metabolites is most likely to occur?

Accepted Answer

Increased abundance of butyrate-producing bacteria and a 2.5-fold increase in butyrate production.

Question 19

Which of the following best describes the effect of artificial sweeteners such as sucralose on the gut microbiota, based on animal studies?

Accepted Answer

Artificial sweeteners can disrupt the balance and diversity of gut microbiota, increasing the abundance of Proteobacteria and Escherichia coli.

The Role of Gut Microbiota in Nutrition and Human Health

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