Topic 7 - Harder stuff Flashcards
Low FODMAP diet
- Leads to increased Actinobacteria
- A high FODMAP diet has a decreased abundance of bacteria that are involved in gas consumption
- Leads to a reduction in IBS
Fibre & prebiotics
- Leads to increased microbiota diversity AND SCFA production
- Leads to a reduction in Type 2 diabetes & cardiovascular disease
Difference in microbiomes b/w breastfed and bottle-fed babies
- Breast fed babies have a lot more Actinobacteria (Bifidobacterium, lactobacillus)
- Have HMOs which are digested by specific bacteria in infant GI tract and act as prebiotics by enriching certain beneficial bacteria
- They also promote the release of SCFAs that feed on infant gut
- Bottle fed babies have more diverse microbiota; more Bacteroides and Clostridial species
- More pathogens
What are the 6 benefits of HMOs?
- They help Bifidobacteria to grow & proliferate
- They competitively exclude pathogens from binding
- Decoy for other microbes to attach to so they can be removed
- Macronutrient digestion
- Development of mucus layer
- HMOs affect bifidobacteria & promote growth of SCFA
What are the 3 key effects of SCFAs?
- They help the growth of enterocytes and use them for energy harvest
- Involved with anti-inflammatory cytokines
- Involved in immune modulation
How are gut microbes involved in immune development?
- Induction, training, & function of the immune system is facilitated by microbes
- Allows immune system to work out which microbes are good and which cause disease
- If the immune system does not work properly, food allergies and autoimmune disease can develop
How does the gut microbiome in the first few weeks compare to later in life?
- The gut microbiome is dynamic in the first few weeks of life; lower diversity, higher variability
- Gut microbiome transitions to higher diversity, lower variability as development proceeds
What are 3 things that can lead to disruptions on gut microbiota?
1) infections
2) antibiotics
3) changes in diet
What types of bacteria are found in the placenta?
- nonpathogenic commensal microbiota
- firmicutes, tenericutes, proteobacteria, bacteroidetes, fusobacteria
What are the first colonizers of the infant gut in vaginal birth?
facultative anaerobic bacteria, like Staphylococcus
What is the bacterial composition of C-section babies like?
- less diverse
- absence of Bifidobacterium and Bacteroides species
What are some health consequences of C-section babies?
- increased risk of allergies and asthma
- associated with higher body mass and childhood obesity
What are the 4 factors that are known to alter gut microbiome & associated with higher rate of C-section surgery?
- Diet
- Antibiotic exposure
- Gestational age
- Host genetics
What are some negative effects of being a preterm infant?
- Higher level of potential pathogens
- High interindividual variability
- Reduced microbial diversity
- Harbour increased levels of facultative anaerobic microorganisms (e.g. Lacobacillus)
- Delayed maturation of immune system (higher risk of infection)
- Lower levels of bifidobacterium
- Necrotizing enterocolitis (NEC) is a serious gastrointestinal disease
- Increase in proteobacteria and decrease in firmicutes before diagnosis of NEC
What are some of the short vs long term benefits of breastfeeding?
Short-term: lowered risk of infectious diseases in childhood
Long-term: lower risk of obesity, protection against type 2 diabetes, increased performance on IQ tests
How does the gut microbiota change after the introduction of solid foods?
- More complex microbiota
- Bifidobacteria proportions drop as microbiota diversifies
- Facultative anaerobes decrease and strictly anaerobic clostridia increase
- Proportions of bacteroides remain unchanged and are one of the most predominant groups in infant after weaning
- Higher prevalence of butyrate-producing bacteria
How do the functions of the microbiota differ in children vs adults?
- Children → ongoing physical development; DNA replication, repair,
- Adults → inflammation & increased risk of adiposity (obesity); synthesis of Vitamin B12, folate
What are the main external factors that can affect the composition of the microbiota in healthy adults?
- Infection
- Major dietary changes
- Antibiotic therapy
- Medications
What kind of elderly person has the highest diversity in gut microbiota?
An older adult living in a community setting who consumes a low fat / high fibre diet that includes a variety of foods
Kids have higher _____ than adults
Bifidobacterium
What is the gut microbiota of old people like?
- Higher Bacteroidetes (more than Firmicutes) and
- Proteobacteria
- Less Actinobacteria (esp Bifidobacterium)
- A centenarian has more pathobionts and less butyrate-producing bacteria
- Lower microbial diversity is associated with HIGHER frailty + inflammation
- In old people, composition of gut microbiota shifts towards LESS DIVERSITY and more proinflammatory species
