Dr. 1
Define the term probiotic. (Make sure you include the three components of this definition and use your own words—DO NOT copy the statement from the slide).
Probiotic is a term used to define microorganisms that are believed to have health benefits to humans when consumed.
When did the NIH human microbiome project begin and what were its two major objectives?
NIH human microbiome project began in the year 2005. Its two major objectives are to identify microbes present human body and identify their role in human health and disease
Which different mechanisms were suggested through which microbiota may contribute to colorectal cancer?
Microbiome can contribute to colorectal cancer by the production of toxic and genotoxic bacterial metabolites that can lead to mutations by binding specific cell surface receptors and affect intercellular signal function. These metabolites include: Secondary bile salt transformation, bacterial B-glucuronidases, production of hydrogen sulfide, production aglycones, production of aromatic amines by azoreductases, production of aromatic amines by nitroreductases, generation of acetaldehyde, desulfation of bile acids and generation of reactive oxygen species
Look up any standard nutrition text and list the names of primary and secondary bile acids.
Primary bile acids: - Cholic acid and chenodeoxycholic acid.
Secondary bile acids: - deoxycholic acid and lithocholic acid.
Describe the mechanism through which the secondary bile acids resulting from microbial action relate to the risk of colorectal cancer.
Gastrointestinal tract cells exposed to high concentrations of bile acids generate cells with oxidative stress. Cells with oxidative stress that don't undergo apoptosis develop into cells with unrepaired DNA damage and apoptosis resistant cells. These mutations are accumulative, and the cells continue to be repeatedly exposed to high concentrations of bile acids leading to oncogenic mutations and finally gastrointestinal cancer.
Dr. 2:
Define the term prebiotic. Make sure you include the three components of the prebiotic definition?
Prebiotic is a term used to define nondigestible food ingredients which improve human health by selectively stimulating the growth and activity of bacteria in the colon. Prebiotics can't be hydrolyzed or absorbed in the upper gastrointestinal tract, they are selective substrates to beneficial bacteria and have the ability to favourably alter colonic flora.
Explain Dr. 2 statement that all of us consume prebiotics.
Prebiotics are widely consumed by everybody because they are available in general diets comprising of fiber and other forms of carbohydrates. While most Prebiotics are fiber not all fiber are prebiotic (they don't elicit beneficial microbial activity in the colon).
Look up what are SCFA?
These are Short-chain Fatty Acids (SCFA).
Formic acid and isobutyric acid.
Are they harmful or beneficial?
The SCFA are produced when dietary fiber in the colon is fermented. They are beneficial because they have anticarcinogenic properties.
Explain what Dr. 2 mentions about the SCFA?
The SCFAs produced in the colon act as a source of nourishment to colonocytes. This nourishment is essential for increased cell growth and maintenance of gut physiology.
What were Dr.2 recommendations about prebiotic intake?
Prebiotic have positive health benefits because they change microflora in the colon and play significant roles in cancer prevention. However, they should not be over consumed because overconsumption can lead to tolerance.
What does Dr. 2 mention about the public health message?
Prebiotics and high fibre diets play a role in cancer prevention. However, most populations consume low fibre and prebiotic levels. Consequently, there is a need to increase intake of dietary fibre and prebiotic supplements.
Dr. 3:
Define the term symbiotic.
A synbiotic is a mixture of probiotics and prebiotics that has beneficial effects on a human host by improving dietary microbial supplements in the GIT (gastrointestinal tract. Synbiotics stimulate the metabolism and growth of selective health promoting bacteria.
How are pro/pre/synbiotics supposed to affect the risk of colorectal cancer (CRC)?
Pro/Prebiotics exert specific beneficial effects of intestinal microbes and boost indigenous growth and maintenance of beneficial microbiota and reduce risk of colorectal cancer
Which stages (write names of stages) of CRC are affected by pro/pre/synbiotics?
The stages affected by pro/pre/synbiotics are DNA damage, Cell proliferation, promotion, and metastasis.
All speakers
Bifidobacterium species such as B. lactis, B. longum, B. breve, Lactobacillus species such as L. rhamnosus, L. johnsonii, and L. plantarum.
Fructo-oligosaccharides, galacto-oligosaccharides, inulin, soya-oligosaccharides and pyrodextrins.
Did the speakers mention any prospective cohort studies of prebiotic and probiotic exposure in relation to health outcomes?
Prospective studies in probiotic exposure are involved in identifying the different physiological effects and benefits of various lactic acid bacteria species and their modulation of the immune system. These prospective studies are geared to investigating mucus adherence and probiotic bacteria ability to adhere to epithelial cells in colon among cancer patients. Prospective prebiotic studies would focus on function, safety, and product formulaion. Other studies in prebiotic would serve as a correlation for measurable physiological outcomes or benefites against microbiota at specific sites. Areas of future research mentioned are the effect of prebiotic inulin in across ages and the different levels of prebiotics in fermented and nonfermented foods.
Look up what is a cross-over study from a reputable source (not Wikipedia!).
A cross-over study is a study design in which the administration of two or more experimental treatments is administered to the same group of patients or subjects. The treatments are administered in a specified or random manner (Cross over study design).
Copy the link/source and give it below your answer. But answer the question in your own words.
http://www.medicine.ox.ac.uk/bandolier/booth/glossary/cross.html
Works Cited
"Crossover Study Design." Medicine.ox.ac.uk. N.p., 2016. Web. 12 Apr. 2016.
