11 - Probiotics Flashcards
define a probiotics
live organisms which when administered in adequate amounts, confer a health benefit to the host
define abiotics
probiotic strains that have been inactivated by lysis, heat, or UV irradiation and have demonstrated some effectiveness in downregulating the inflammatory response in intestinal epithelial cells
define prebiotics
non-digestible CHO that serve as “food” for probiotics to help them grow and remain in the digestive system
true or false: all non-digestible CHO are prebiotics
false - they must meet specific scientific criteria
define synbiotics
food ingredients or dietary supplements combining probiotics & prebiotics in a form of synergism
what are the 4 categories of microbial populations in the gut?
1) autochthonous microbiota
2) normal microbiota
3) pathogens
4) allochthonous microbiota
define autochthonous microbiota
population of microbes that are present in large numbers and permanently colonize the host
define a normal microbiota
microorganisms that are frequently in the gut, but can vary in number and be sporadically absent
define a pathogenic microbiota
microorganisms that are periodically acquired by can persist and cause infection or disease
define allochthonous microbiota
are microbes from another origin that are present temporarily (most probiotics are also allochthonous)
what do probiotics usually contain?
LAB and Bifidobacteria
more specifically:
- Lactobacillus
- Bifidobacterium
what do probiotics sometimes contain?
- yeast: Saccharomyces boulardii
- E. coli Nissel
what are the criteria for the selection of probiotic strains? (6)
1) origin of strains
2) biosafety
3) tolerance to acid and bile salts
4) adhesion to intestinal cells
5) production of antimicrobial substances
6) utilization of prebiotics
where should probiotics originate?
human origin, but this criteria doesn’t hold as much weight anymore. now the biochemical activity is more considered.
regarding biosafety, an organism must be ________
GRAS - generally recognized as safe
explain the third criteria for probiotic strains
probiotic strains must be tolerant to acid and bile salts to reach the GIT. (unless they’re administered as enteric-coated capsules)
explain the fourth criteria for probiotic strains
strains should be able to adhere to intestinal cells and colonise the GIT at least temporarily
explain the fifth criteria for probiotic strains
LAB can produce lactic acid, H2O2, and bacteriocins, all of which limit the growth of pathogenic bacteria
explain the sixth criteria for probiotic strains
probiotics should be able to use fructo oligosaccharides (FOS)
how are probiotics beneficial to the immune system?
shift the production of cytokines from the inflammation-inducing interleukin-12 pathway to the anti-inflammatory IL-10 pathway
how are probiotics beneficial to the mucosal barrier?
Dysfunction of the GIT barrier can lead to inflammatory bowel disease, some probiotics enhance this barrier by encouraging production of protective proteins such as mucins
how are probiotics beneficial with regard to the exclusion of pathogens?
: Probiotics appear to inhibit the attachment of bacterial pathogens to the GIT epithelial cells by physically blocking the receptor sites.
what are some proposed health benefits of probiotics?
- lactose digestion
- weight loss
- resistance to enteric pathogens
- anti-carcinogenic
- antihypertensive
- reduction of ulcers
- reduction of urogenital infections
what cocktail of probiotics was administered to fruit flies? what happened?
L. plantarum, L. fermentum, Bifidobacteria longum;
almost doubled their lifespan via gut-brain axis
