Prebiotics Flashcards
what is probosis
introducing large quantities of beneficial bacteria to the host
what is prebiosis
provide bacteria present with dietary adjuncts that will selectively feed the beneficial bacteria and increase their number
what is a prebiotic
a substrate that is selectively utilised by host MOs conferring a health benefit
what is a substrate
any substance that can be used for an organisms nourishment
can whole foods be a prebiotic?
yes, however in most cases they’re in too low concentrations- could be fortified
what are fortified foods? are they pre biotics?
addition of vitamins- no
can a prebiotic be a MO or AM?
no has to be a substrate
can the substrate have adverse effects?
no e.g. excessive gas
TF: breast fed have higher faecal pH, stool frequency and consistency than non breast fed
FALSE- have higher
what is breast milk known to contain? what affect does this have on the child?
human milk oligosaccharides: Fructo OS, Galacto OS
enrichment of bifidobacter and lactobacilli in the gut
what part of the gut do we want probiotics to get to?
distal end- not broken down by host enzymes
example of a bacteria that causes health benefits and we may want to target with a prebiotic? please give then health benefits
bifidobacter
increased amounts of lactic acids and SCFAs
storage advantage of prebiotics over probiotics?
don’t need to be stored specially- in a fridge
how does lactulose act as a prebiotic?
reaches distal parts of the gut where its selectively fermented
able to enrich bifidobacter
2 other clinical utility of lactulose?
osmotic laxative
hepatic encephalopathy
how does lactulose act as a laxative
drops the pH of the intraluminal space- increases osmolarity which has a laxative effect
what can hepatic encephalopathy lead to an accumulation of?
products of bacterial metabolism- aren’t cleared as well as the liver is impaired
how does poor liver function lead to encephalopathy?
build up of ammonia and toxins produced by bacteria which eventually cross the BBB and result in neurological effects
how does lactulose treat hepatic encephalopathy?
- the colonic bacteria use ammonia as a nitrogen source for protein synthesis
- enrichment of bifidobacter, these produce lactic acid which DROP THE PH= conversion of ammonia to ammonium NH4
which is less effective at crossing the BBB - drop in pH is antagonistic to ammonia producing organisms
effects of inulin when used to treat constipation? which bacteria does it nourish/ inhibit and what is produced
increased in bifidobacter and anaerostipes
increased SCFA production
drop in bilophila
TF: the drop in bilophila caused by inulin consumption is good? explain
TRUE
hydrogen sulphide producers- this is bad.
when they drop improved gut barrier function
patient consuming inulin had _____ stool frequency
increased
