Probiotics and Prebiotics

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How does probiotic bacteria originate in a baby and what impact does this have?	-Newborns are born with a sterile gastrointestinal tract (GIT) -This is inoculated within first few days from consumption of breast milk -This improves digestion, coats the bowel and protects the infant from pathogens
What factors affect the microbial composition in the gut of a newborn child after the first few days?	Feeding, hospitalisation and antibiotic use
When is someone classed as having good intestinal health?	When there is more than 85% of good microbes and less than 15% of bad microbes
Define probiotics	Live microorganisms that when administered in adequate amounts will confer a health benefit on the host
What 3 criteria are used to select effective probiotics?	1)Safety e.g. origin, identity and resistance to mutations 2) Functional e.g. adhesion, colonisation of the mucosal 3) Technological e.g. growth properties in vitro and during processing
What must an effective probiotic be?	Non-pathogenic, non-toxic, able to survive the passage through the GIT, remain viable during storage and use and exert one or more beneficial effects on the host
Most strains are probiotics are members of which group? and name two examples.	-Members of the Lactic Acid Bacteria -e.g. Bifidobacterium and lactobacillus species
What type of food sources are probiotics found in and give three examples	-Found in fermented foods -e.g. cheese, yogurt, sausage (salami), sauerkraut
Probiotics can also be found in supplements. However, in terms of supplements, what is it important to note?	-Not all probiotic supplements are the same e.g. they may contain different genera, species or strains -Not all probiotic supplements will exhibit the same health benefits (claims should only be made if there is proof from carefully designed studies)
List 4 health benefits of probiotics	1) Regulate the balance of gut microflora 2) Improve digestion of lactose 3) Stimulation of the immune system 4) Other benefits e.g. lowering serum cholesterol levels and promoting anti-carcinogenic effects
Explain how probiotics can regulate the gut microflora	-Improve gut mucosal barrier by coating the intestinal epithelium with probiotics which decreases pathogen adhesion and regulates the balance of gut microflora -Probiotics produce antimicrobial substances such as organic acids and bacteriocins which inhibit pathogen adhesion -Probiotics reduce gastrointestinal infections such as antibiotic associated diarrhoea, travellers diarrheoa (e.g. E. Coli) and acute diarrheoa (e.g. Rotavirus)
Explain how probiotics improve the digestion of lactose	-Probiotics increase production of B-Galactosidase (lactase) which breakdown lactose into simple sugars (glucose & galactose) which enhances the absorption of these sugars -This helps to alleviate symptoms of lactose intolerance or lactose maldigester
Explain how probiotics increase stimulation of the immune system	-GALT or gut-associated lymphoid tissues are considered to be the largest intrinsic protection in the human body against infective agents -Around 80% of immunoglobin producing cells are found in the small bowel -Gut microflora essential for mucosal immune stimulation and amplification of immuno-competent cells -Several probiotics are claimed to stimulate the immune system by up-regulating immune response to possible pathogens or to vaccines and down regulating inflammatory response
Explain how probiotics lower serum cholesterol levels and promote an anti-carcinogenic effect	-Deconjugation of bile acids by probiotics leads to reduction in lipid absorbance -Binding of cholesterol to cell surface of probiotics leads to transit out from GIT -Suppressed the conversion of pro-carniogen to carcinogen which therefore reduces the amount of carcinogen in intestine
Define prebiotics	Non-digestible food ingredients that beneficially effect the host by selectively simulating the growth and/or activity of one or a limited number of bacteria in the colon
List the characteristics that a prebiotic must have	-Dietary ingredient that services intact till it reaches the large intestine -Has specific metabolism directed towards helpful bacteria rather than harmful bacteria -Active at a nutritionally feasible dose -Slow fermentation through the colon
Give an example of a prebiotic and describe why it makes a good prebiotic	-Non-digestible oligosaccharides (NDO) seem to exert the best prebiotic effect -They are short chain carbohydrates that occur widely in nature and have a glycosidic bond in a spatial configuration which is able to resit hydrolytic and digestive enzymes but is sensitive to metabolic activity of colonic bacteria -Colonic bacteria are able to ferment NDOs to produce short chain carboxylic acids and gases as well as increase metabolic energy, growth and proliferation
Give two examples of non-digestible oligosaccharides which are probiotics	-Inulin-type fructans (fructooligosaccharide, FOS) -Soybean oligosaccharide (raffinose and stachyose) -Lactulose
In what sources can probiotics (NDOs) be found?	NDOs typically found in plants e.g. seeds and tubers but they can also be found in smaller quantities as free sugars in human milk
Name two sources of fruit-oligosaccharides (FOS) and the typical amounts you would find within those foods	-Jerusalem artichoke (17-21g/100g) -Garlic (16g/100g) -Raw Onion (1-8g/100g)
What are the benefits of prebiotics?	-Main benefits of prebiotics are same as probiotics due to prebiotics "feeding" or stimulating the probiotic bacteria such as bifidobacterium and lactobacillus species -Specific benefits of prebiotics include: production of short chain fatty acids e.g. acetate, butyrate and propionate and improved mineral absorbance and balance due to acidification of colonic contents which raises concentration of ionised materials (e.g. calcium) thus favouring passive diffusion/absorption

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	Creado por Adam Hollens hace más de 9 años