Transcript Prebiotics and Probiotics

Group 5:
Nancy Elwell
Emily Lynch
Laura Mello
Virginie Vicks
Prebiotics and
Probiotics
Effects on Obesity and Weight
Loss
Topics that will be discussed
★ Defining obesity
★ Defining Prebiotics and Probiotics
★ Metabolism, physiology,
genetics, and mechanisms of
pre/probiotics
★ Recent findings of peer reviewed
studies done regarding dietary intake
of pre/probiotics and how this relates to obesity and weight loss
Perspective on Obesity
● Obesity can be defined, diagnosed,
and studied according to many factors
● waist circumference
● various BMI standards
● body composition
● disease associations
● lifestyle related causes
● psychosocial factors
● economic factors
● genetics
“All of these factors each have their role in contributing to obesity but not one
single answer or cause exists.”¹
Defining Obesity
● Common example definition of obesity
“disturbance of thermodynamic of energy balance, primarily through increased
intake and decreased expenditure of energy.”¹
● More current and accepted definition of obesity
“a condition in which energy stores of the body (mainly fat) are too great.”²
● Because there are so many causes of obesity, it is now more defined by type in
current medical dictionaries
Obesity can be influenced and/or manipulated by:
● degree by which digestion, absorption, and secretion of macronutrients occur
● hormones which regulate energy intake such as the peptide YY, ghrelin, and leptin
which are responsible for satiety, etc.
● gene expression
● inflammatory response
● glucose metabolism
Obesity can thus be indirectly affected by the gastrointestinal tract
(GIT) microbiota that secondarily influence these mechanisms.
What does prebiotics and probiotics have to do with
influencing obesity?
Defining Prebiotics
“...nondigestible food ingredients
that serve as substrates to
promote the colonic growth
and/or activity of selected
health-promoting species of
bacteria.”¹
Foods Containing Prebiotics
Foods Containing Prebiotics
Grains, oat
bran, oatmeal,
and baked
products
Yogurt,
breast milk,
and other
dairy
products
Onion, garlic,
chicory root, root
veg, bananas,
leeks, artichokes,
legumes,
cabbage, etc.
Infant formula
and other
functional
foods and
supplements
Prebiotics in foods. (2012) Current opinions in biotechnology 187-191
Defining Probiotics
“...products that contain
specific strains of microorganisms in sufficient
numbers to alter the
microflora of the
gastrointestinal tract, ideally to
exert beneficial health effects.”¹
Foods Containing Probiotics
fermented dairy
products such as
milk, cheeses, and
yogurt
Soy and miso
foods
A variety of fruits
and vegetables
fermented fruit
juices, wines,
functional foods
and supplements
Gupta, V., Garg, R. (2009). Probiotics. Indian Journal of Medical Microbiology, 27 (3), 202-9.
Dimitris Charalampopoulos, R.A. (2012). Prebiotics in foods. Current opinions in biotechnology. 187-191.
Metabolism and
Physiology of Prebiotics in
the Setting of Obesity
… And studies that have been done
Functions of the intestinal microflora related to
Prebiotics
Prebiotics and probiotics are keys for good
gut health. The gut flora is responsible for
more that just digestion. Prebiotics can
selectively stimulate the growth and the
activity of the intestinal bacteria causing
changes in the overall microbial population
which are health promoting for the host.
Gut microbiota can affect obesity.
Actions & Efficacy of Prebiotics
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Prebiotics are food for probiotics
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Effective modulators of the gut microflora: improve
gut barrier function and host immunity
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Stimulate the life cycle and increase the metabolic
activity of healthful bacteria (restore dysbiosis)
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Reduce potential pathogenic bacteria subpopulations
Types of Prebiotics:
FODMAP- carbohydrates (oligosaccharides),
disaccharides, monosaccharides and related
alcohols that are poorly absorbed in the
small intestine:
● Inulin
● Oligofructose (FOS)
● Galacto-olisaccharides
● Lactuloses
Prebiotics-Effect on Obesity & Weight Loss
● Evidence that increased dietary prebiotic intake decreased
inflammation, improves glucose metabolism and decrease obesity by
lowering the fat mass
● Reduction in serum cholesterol is seen in hyperlipidemic patients
● Prebiotic fibers bring lower energy density and a higher volume in
promoting satiety (reducing hunger, delaying gastric emptying and
reducing nutrient utilization)
Key Factor:
~ Prebiotic is an asset in weight loss management but not a solution. ~
Gene Expression of Prebiotics
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Prebiotics modulate the gene expression and metabolism that influence the gut
microbiota
Clear genetic differences in the microbial composition between obese and non-obese
patients
Prebiotics lower plasma glucose and cholesterol levels
Prebiotic consumption can change the fate of obesity by improving dysbiosis of the gut
microbiota in increasing firmicutes and decreasing bacteroidetes.
Increased proglucagon mRNA increase plasma Glucagon-like Peptide 1 (GLP -1) Levels.
Increase Regenerating islet-derived protein 3 gamma
(Reg3g) expression in the colon area
Gut peptides and prebiotics related → stability of the gut ecosystem
Prebiotic Study: clinical trial
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Efficacy of prebiotics on both human and animal (mice)
Measuring the success of prebiotics in nurturing “good” GIT microbial communities
Can they change the destiny of metabolic diseases such as obesity and DM2?
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Context and parameters of the study:
This study examined the effect of prebiotic
fibers and gut microbiota alternation
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Results:
Lipid-lowering effect
Inflammation reduction
Improvement of gut microbial profile with
prebiotic fibers
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Researchers concluded:
Lean and obese physiology will respond
differently to treatment designed to modulate
the gut microbiota. More future research is
needed to understand the process.
Metabolism and
Physiology of Probiotics
in the Setting of Obesity
...And the studies that have been done
Probiotics-Effect on Weight Loss
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One study investigated the anti-obesity effects of probiotic, lactic acid bacteria:
Male mice were divided into 4 groups:
NDC (Normal diet and placebo)
HDC (high-fat diet and placebo)
LGLAB (low-fat diet and Lactobacillus plantarum)
HGLAB (high-fat diet and L. plantarum)
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Results: both -GLAB groups showed:
Lower body weight
Reduction in body fat
Reduction in serum and hepatic triglyceride
Reduction in serum insulin and leptin levels
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Results suggest that probiotics have anti-obesity effects
Results may contribute to the development of functional food and probiotics therapy for the
treatment and prevention of obesity¹
Effect of GIT microflora on obesity
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The effect of GIT microflora on obesity were studied:
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Context and parameters of the study:
Mice were fed diets high in saturated fats (72% energy as fat)
for 4 wks
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Results and researchers’ conclusions:
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Mice showed endotoxemia, as evidenced by high
plasma endotoxins
Free saturated acids cause obesity, insulin resistance,
and T2DM
Increases calorie consumption increases bacteria that
promote inflammation and risk of metabolic diseases
Moderate calorie consumption encourages optimum
ratios of bacteria and reduces the risk of metabolic
diseases
Probiotics Affect Gene Expression
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Glucagon: The hormone stimulated during hunger; it has been found to suppress appetite
One study examined the effect of the probiotic Lactobacillus paracasei subsp (L. casei W8) on
Glucagon-like peptide (GLP-1) response:
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Context and parameters of the study:
21 human participants completed 3 test days testing the effect
of L. casei W8. On the fourth day, the same meal was
consumed by all participants. GLP-1, insulin, and glucose
were tested after the meal.
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Results:
Probiotic L. casei W8 lowered food energy intake but Appetite,
Overall Glucose, and Insulin Response were NOT affected
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Researchers concluded:
More study needs to be done to clarify the effects of Probiotics
on the expression of Glucagon Encoding Gene.
Study: Diet Trumps Genetics
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Mammals show distinct variations in GIT bacterial community between individuals
Researchers asked: Is this difference due to host genetics or dietary intake?
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Context and parameters of the study:
This study examined the effect of dietary variations on
the GIT microbiota of 200 mice deficient in genes
relevant to host-microbial interactions with 200 mice not
deficient in these genes
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Results:
Consumption of a high-fat, high-sugar diet altered the
GIT microbiota REGARDLESS of the differences in host
genotype
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Researchers concluded:
Diet plays a crucial role in shaping individual variations
in GIT microbiota. Diet was the primary drive for the
variations, NOT genetics
Prebiotic and Probiotic
Fecal Transplant and
Obesity
...And studies that have been done
Fecal Transplant
Defining Fecal transplant:
the process of transferring fecal matter from one
person to another to alter the fecal microbiome of the
recipient, often used to treat infectious disease such as
C. diff.
How?
The standard way that this transfer is accomplished is
by removal of fecal matter from a donor by
colonoscopy, preparation of slurry of donor fecal
matter, which is then transplanted into the colon of the
recipient through colonoscopy.
Fecal Transplant Studies
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In one study research showed that fecal transplant of probiotics affects the energy balance
equation resulting in weight management.
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Context and parameters of study:
Fecal transplant of lab mice after sterile preparation
of GIT
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Results:
Gut microbiome contributed to nutrient absorption
and regulated host genes that affect fat
development.
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Researchers’ conclusion:
Promising findings supporting probiotic use but
unclear how results would translate to humans
Other Fecal transplant Studies: Host Genetics
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Influence the microbiome and obesity, most inheritable taxa were - Christensenellaceae.
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Context and parameters of study:
When Christensenella minuta were inoculated into the
obese-associated microbiome of “germ-free” mice
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Results:
The C. minuta reduced weight gain and altered the
microbiome of the recipient mice, recipients take on
some metabolic features of donor
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Researchers’ conclusion:
Diet supercedes¹ (particularly from variety of
polysaccharide intake and when the recipient diet is
switched from a “low-fat” polysaccharide diet to a
“Western” diet high in fat and sugar.)²̕ ³
Limitations of All Studies Discussed
● Many studies measure
success by means of…
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serum cholesterol
appetite
plasma glucose
normalizing dysbiosis
microbial profile of GIT
only a few studies measured
success in terms of weight
● Those that measured success
in terms of weight…
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weight loss is “promoted”
secondary to improvement of other
factors but studies have
inconclusive results
most studies done are animal (i.e.
mice, pig) based studies and
cannot be directly comparable to
humans
human studies are subject to
variables and results are
vulnerable to error
Limitations continued...
Fecal transplant study limitations:
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Few studies have been done
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Safety of methods are uncertain
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Methods are only well established for
treatment of infectious disease and not
for microflora manipulation for the
purpose of weight loss
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All current studies are animal-based and
are not comparable to humans
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Evidence thus far has suggested only
temporary success after fecal transplant
in mice but diet determines ultimate
microbiome population
Strengths of All Studies and Concluding Remarks
Strengths and concluding remarks
concerning the collective body of
evidence:
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Studies consistently and objectively
demonstrate probiotic and prebiotic
intake without bias
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Most studies done are animal based in
controlled environments, have little
margin of error, and are not subject to
human participant elements
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Consistent with beneficial findings that
support prebiotics and probiotics on GIT
health and for the host as a whole
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Demonstrate biological evidence that
symbiotics impact conditions of
inflammatory response, blood glucose
and insulin resistance, adiposity, serum
cholesterol, and overall GIT microbial
profile
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Provides strong support for prevention of
obesity and weight managment but more
studies are required with regards to
weight loss