Probiotics Flashcards
What are probiotics?
live microorganisms which when administered in adequate amounts confer a health benefit to the host
What is abiotics
Typically consist of 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.
What is prebiotics
are non-digestible carbohydrates that act as “food” for probiotics. Prebiotics help probiotics grow and remain in your digestive system. Not all non-digestible carbohydrates are prebiotics. All prebiotics must meet specific scientific criteria.
What is synbiotics
Food ingredients or dietary supplements combining probiotics and prebiotics in a form of synergism
There are four major categories of microbial populations in the gut
- Autochthonous microbiota are populations of microbes that are present in large numbers and permanently colonize the host
- Normal microbiota are microorganisms that are frequently in the gut, but can vary in number and be sporadically absent
- Pathogens are microorganisms that are periodically acquired can persist and cause infection or disease
- Allochthonous microbiota are microbes from another origin that are present temporarily (most probiotics are also allochthonous)
Is e.coli always pathgenic?
•Although E. coli is sometimes considered a foodborne pathogen one specific strain E. coli Nissle (sold under the trade name Mutaflor) is considered a probiotic
Most probiotic formulations
- Probiotic preparations generally contain LAB and Bifidobacteria which are normal constituents of the human gastrointestinal microflora
- Lactobacillus and Bifidobacterium species are generally considered to be beneficial to the health of their human hosts
- However, the use of other microorganisms is also possible: Sometimes the yeast Saccharomyces boulardii is used
6 criteria for selection of probiotic strains
- Origin of strains
- Biosafety
- Tolerance to Acid and Bile salts
- Adhesion to intestinal cells
- production of antimicrobial subtances
- utilization of prebiotics
Expand on origin of strains criteria selection
One criteria originally proposed was that all strains should be from human origin. However, LAB exist in diverse environments, and now it’s the biochemical activity that’s considered, not the origin.
Expand on biosafety criteria fro selection of prebiotics
Lactobacillus and Bifidobacteria have low pathogenic potential. Enterococcus can contain opportunistic pathogens. The use of intestinal isolates raised the concern of biosafety. The organism must be generally recognized as safe (GRAS).
Expand on criteria: tolerance to acid and bile salts for probiotics
- Tolerance to Acid and Bile Salts: Probiotic strains must be tolerant to acid and bile salts in order to reach the GIT (specifically the colon)
An exception to this situation is when probiotics are sold in enteric-coated capsules designed to reach the colon (Escherichia coli strain Nissle)
*** There is also evidence that milk and yogurt provide some protection to probiotic microorganisms.
Expand on adhesion to intestinal cells criteria for probiotics
Strains should be able to adhere to intestinal cells and colonize the GIT, at least temporarily
Expand on the production of antimicrobial substances for probiotics
4.LAB produce a number of substances that are inhibitory to other bacteria including: lactic acid, hydrogen peroxide, and bacteriocins. Lactic acid also lowers the pH of the colon, and this low pH affects the ability of pathogenic bacteria to grow in the colon and vagina. Hydrogen production is also particularly good at discouraging urogenital infections.
Expand on utilization of prebiotics for probiotics selection
4.The relationship between prebiotics and probiotics is also important. Probiotics should be able to use fructo-oligosaccharides (FOS).
The mechanism of action is not fully understood, but studies indicate that there are three major avenues through which probiotic cultures have beneficial activities on the GIT:
- Interaction with the Immune System: Some probiotics appear to shift the production of cytokines from the inflammation-inducing interleukin-12 pathway to the anti-inflammatory IL-10 pathway
- Strengthening 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
- Exclusion of Pathogens: Probiotics appear to inhibit the attachment of bacterial pathogens to the GIT epithelial cells by physically blocking the receptor sites.
How probiotics can be beneficial to lactose digestion
How probiotics can be effective for weight loss
Microbiota with less efficient energy use mechanisms
How probiotics is effective against enteric pathogens
Colonization resistance, unfavorable conditions for pathogens (lower pH, bacteriocins, short-chain fatty acids)
How probiotics are essential for anti-carcinogenic properties?
Antimutagenic activity (bind mutagens), lower pre-carcinogenic enzyme activities (nitroreductase, azoreductase) of colonic bacteria, influence on secondary bile salt concentrations
How probiotics can be antihypertensive
Peptidase activity on milk produces a peptide that acts on angiotensin-1 converting enzyme inhibitor to lower blood pressure in hypertensive animals
How antibiotics can be helpful against ulcers
LAB produce bacteriocins that are effective against H. pylori
How probiotics can be effective against urogenital infections?
Adhesion to urinary and vaginal cells, competitive exclusion, production of inhibitors (biosurfactants, hydrogen peroxide)
What probiotic mix was able to expand fruit fly life almost by two and potential outcomes
- A probiotic formulation that included L. plantarum,L. fermentum, and Bifidobacteria longum along with a prebiotic (Triphala) was able to almost double the lifespan of fruit flies
- The mechanism was through the gut-brain-axis of communication
- This means that it could potentially be a therapeutic tool in neurodegeneration, diabetes, obesity, cardiovascular disease and other age-related chronic diseases
What is Ulcerative colitis and what bacteria is thought to play a role in it?
- Ulcerative colitis (UC) is a chronic inflammatory bowel disease, the underlying causes are unknown
- It is thought that pathogenic E. coli play a role in the establishment and in “flair-ups” of this disease (ANSC350)
What is used right now to maintain remission of UC
•At the moment mesalazine is used to maintain remission in UC patients
What is the proposed new solution for UC
- There are several peer-reviewed studies indicating that E. coli Nissle is almost as effective as mesalazine in maintaining remission of UC
- There are three proposed mechanisms:
- Direct antimicrobial effect (bacteriocins)
- Bacterial-epithelial crosstalk
- Immune-modulatory properties
Are S. thermophilus and L. bulgaricus in yogurt probiotics?
A bacteria that is able to colonize vagina following oral intake
- L. rhamnosus has been shown to colonize the vagina following oral intake
- In a placebo-controlled trial of 64 healthy women given oral capsules of L. rhamnosus for 60 consecutive days:
- Women who had the probiotic had a depletion of yeast at day 28
- Women who had the probiotic had a decrease in the coliforms present at day 28, 60, and 90
Who is Gregor Reid?
- Received 1.4 million dollars from Global Affairs Canada to start a company/ project called Fermented Food For Life
- The project distributes one-gram sachets that contain probiotic Lactobacillus rhamnosus GR-1 bacteria and a unique Streptococcus thermophilus strain for approximately $0.50 each
- Each sachet can produce 100 Litres of yogurt
These sachets are distributed to “producers” who are “poor” women in Uganda, Kenya and Tanzania.
The sachets provide an opportunity to begin businesses and earn a steady income, as the yogurt is very easy to produce.
How probiotics are used in animal nutrition (give concrete examples with chickens and cattle)
- The primary health targets for agricultural animal probiotics are enhancement of animal growth, weight gain, and reduction in the carriage of human enteric pathogens
- Reduced pathogen carriage is of significant interest because a reduction of pathogens at the farm level would result in a reduction in the risk of foodborne illness
- Newly hatched chicks are generally inoculated with bacteria (a 29 species mixture) and this provides resistance to Salmonella
- Cattle given a probiotic cocktail are also more resistant to E. coli O157:H7 colonization
Why probiotic studies are very limited and should be done better?
- The effect of probiotics is likely small (smaller than with conventional drugs) and is likely confounded by age, diet, and lifestyle
- Study results vary with the strains used, the population level of the probiotic cells delivered, the health marker targeted, and the number, age, and condition of the subject evaluated (we don’t know what the minimal dosage is, and we don’t know how frequently you would have to consume the organism to get the desired effect)
- What are the biomarkers for a healthy GIT? No one can agree on this.
Describe Seuz et al., 2018 study and what they found, what was bad and good
•Examined, in both mice and humans, the effects of an 11-species probiotic or an FMT, administered after antibiotic consumption, on the GIT community structure.•Used an invasive endoscopic technique•The probiotic better colonizes after antibiotic treatment in both humans and mice•The probiotic delays the return of the indigenous microbiome•The probiotic delays the return to a homeostatic mucosal transcriptome
What if other combination was used?little participants
What is probiotic regulation status in Europe
- Probiotics are not governed under specific regulatory frameworks
- The Novel Foods Regulation act governs the introduction of newly discovered or genetically modified LAB
- The EU parliament did adopt a new regulation that the health claims of foods must be accompanied by relevant scientific justification
How probiotic are regulated in Canada?
