Probiotics Flashcards
FAO defined probiotics as:
live microorganisms which when administered in adequate amounts confer a health benefit to the host
What are abiotics, and what impact do they have on health?
probiotic strains inactivated by heat or lysis or UV
may help downregulate inflammation in gut epithelial cells
What are prebiotics?
non-digested carbohydrates that serve as “food” for gut microflora (help to retain and grow microflora)
True/False: all indigestible fibre is considered a prebiotic
False; must meet certain criteria
What are synbiotics?
Food with both prebiotic and probiotics (in synergy)
4 categories of microbes in the gut:
- autochthonous - in large numbers, permanently colonize
- normal - frequently in gut, sporadically absent
- pathogens - periodically acquired, may persists (harmful, cause inflammation/disease)
- allochthonous - come from other origin, usually temporary
What are the 2 most common microbes used in probiotics?
Lactobacillus (and other LAB), Bifidobacteria
True/False: E Coli can be used as a probiotic
True; NOT pathogenic strain; specifically E. coli Nissel (Mutaflor)
True/False: yeast can be used as a probiotic
True: Saccharomyces boulardii
Non-Lactobacillus and non-bifidobacteria cultures used as probiotics:
Bacillus (subtilis, clausi) Enterococcus (faecium, faecalis) Streptococcus thermophilus Propionibacterium freudenrichii Saccharomyces boulardii
6 criteria for selection of microbe as use for probiotic:
- Origin of strain (from human/elsewhere)
- Biosafety: low pathogenic potential; should be GRAS
- Acid/Bile salt tolerance (able to reach colon)
- Adhesion: able to colonize intestine temporarily
- Produce Antimicrobial substances (prevent infection)
- Utilize prebiotics: use fructo-oligo-saccharides (FOS)
What are protective measures can be done for low acid/bile tolerance probiotics to help them reach the colon?
milk/yogurt have protective effect
encapsulate in enteric-coated capsule (for E. coli Nissel)
In terms of biosafety, ___ and ____ are nonpathogenic, while ____ carries more risk as it is a ____ pathogen.
Lactobacillus, Bifidobacteria
Enterococcus; opportunistic
How do lactobacillus help prevent pathogen growth in the colon?
lower pH (lactic acid)
bacteriocins
hydrogen peroxide
prevent from binding
3 major ways probiotic cultures benefit the GI tract:
- interact with immune system
- strengthen mucosal barrier
- exclusion of pathogens
How do probiotics interact with the immune system?
promote cytokines for ANTI-INFLAMMATORY pathway (IL-10)
reduce cytokines for inflammatory pathway (IL-12)
How do probiotic enhance the mucosal barrier? What happens if the mucosal barrier is weak?
promote mucin (protective protein) production
dysfunctional mucosal barrier -> inflammatory bowel disease
How do probiotics prevent bacteria adhesion?
physically block receptor sites on epithelial cells in gut
some proposed health outcomes from probiotics: (7)
- improved lactose digestion (lactase production)
- weight loss (less energy efficient gut microbes)
- enteric pathogen resistance (prevent binding/inhibitory substances)
- anti-carcinogenic (bind mutagens)
- antihypertensive (release bioactive peptide from milk -> lowers BP)
- reduce ulcers (LAB -> bacteriocins -> prevent H pylori)
- reduce UTIs (exclusion/inhibition)
What combination of probiotics was found to double the lifespan of fruit flies? What was the mechanism, and what implications does it have?
L. plantarum, L. fermentum, Bifidobacteria longum (+ Triphala prebiotic)
through brain-gut axis of communication
possibly use probiotics to treat/prevent chronic disease (cardiovascular, diabetes, neurodegeneration, obesity, etc)
What is UC (disease), and what is the cause?
ulcerative collitis: type of inflammatory bowel disease
cause is unknown; possibly triggered by E. coli (pathogenic)
What are treatment options for UC?
- mesalazine
2. E. coli Nissel
True/False: E. coli Nissel probiotics are more effective than mesalazine treatment for UC. What are the proposed mechanisms?
False; ALMOST as effective.
- direct (bacteriocins)
- interact with epithelial tissue
- modulate immune system
S. thermophilus and L. bulgaricus are commonly found in _____. Are they considered probiotics? Why or why not?
yogurt
YES: make beta-galactosidase: better lactose digestion
NO: TRANSIENT: do not colonize/proliferate
What is the significance of L. rhamnosus as a probiotic?
When taken orally, can colonize vagina
improve vaginal health (decrease coliforms, yeast, UTIs)
Who is well known for publishing many papers on probiotics and vaginal health, and what project did he pioneer?
Greg Reid
Fermented Food for Life: distribute sachets of L. rhamnosus and S. thermophilus to women in poorer countries (Kenya, Uganda, Tanzania) to make yogurt businesses
How are probiotics used outside of human health?
Agriculture and companion animals
Why are probiotics significant in agriculture? Give 2 examples.
improve animal weight gain, growth, reduce enteric pathogens (that affect health of animal and could spread to humans)
new chicks: inoculated with mixture -> resistant to salmonella
Cattle: given probiotic mixture -> resistant to E. coli O157:H7
What are the inherent limitations of probiotic studies? (4)
- Small effects (less than conventional drugs); hard to measure
- Confounded with other factors (age, diet, lifestyle)
- Effects vary with strain, population (dose), health marker, etc
- No consensus on biomarkers for healthy GI tract
True/False: probiotics can speed up the return to a homeostatic gut microbiome after antibiotic therapy (according to Suez et al.)
False; probiotics will actually DELAY return to normal microbiome; also delays return to homeostatic mucosal transcriptome
Why is there a delay in return to the indigenous microbiome after taking antibiotics, and then probiotics? Is there any benefit in probiotic use after antibiotic therapy?
normal gut flora will resist colonization by probiotics
antibiotics will eliminate gut flora -> probiotics have greater colonization -> take longer to return to normal microbiome
some benefit: probiotics (safe/benign) -> act as “placeholder” until normal population recovers
What alternative therapy from probiotics was found to improve time taken for return to normal gut microbiome?
fecal transplants
True/False: probiotics in europe are not under specific regulations.
True
New probiotics (or GMO) under the Novel Foods Regulation Act *health claims need scientific evidence)
What are the regulations for probiotics in food in Canada?
must be from approved list of organisms
only approved list of marketing claims can be made
If probiotics are marketed as a health product, they are classified as _____. How are health claims regulated?
NHPs (natural health product)
must provide evidence to Health Canada to back up claim
