Transcript Prebiotic effects of almonds and almond skins on intestinal

PREBIOTIC EFFECTS OF
ALMONDS AND ALMOND
SKINS ON INTESTINAL
MICROBIOTA IN HEALTHY
ADULT HUMANS
By: Tess Soper
Introduction: Intestinal Microbiota

Intestinal microbiota play an essential role in
influencing the health of the host
 Good
bacteria: Bifidobacterium spp. and Lactobacillus spp.
 Bad Bacteria: E Coli and C. perfringens
Introduction: Prebiotics

Use as functional food ingredients to manipulate the
composition of colonic microbiota in order to
improve health
 Prebiotic
properties: food oligosaccharides and
polysaccharides (including dietary fiber)
Introduction: Almonds

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
Almond or almond skin can serve as a candidate
food for potential prebiotic effects
Almonds: good source of nutrients and amounts of
potential prebiotic indigestible carbohydrates
Almond Skins:
 4%
of the total almond weight
 Flavonoids in skin: may contribute to the health benefits
associated with almond consumption
Rationale

Purpose: to investigate the effects of daily consumption of
either almonds or almond skins on the composition of the fecal
microbiota and on selected indicators of microbial activity in
healthy adult volunteers

Hypothesis: almonds and almond skins possess potential
prebiotic properties
Methods: Subjects
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•
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48 subjects (24 male and 24 females)
18-22 years old
Similar living environment in dorms
Criteria: good health, nonsmokers, stable
weight
• No antibiotics/meds 3 months prior to study
• No yogurt or products containing
bifidobacteria, lactobacilli, or prebiotics in
the 3 weeks prior to the study
Methods: Study Design

2 week run-in period (dietary restrictions- no nuts),
6 week treatment period (3 groups) , 2 week
washout period (return to normal diet)
Group 1 (The
Control Group):
commercial
fructooligosaccharides
(FOS), 8 g/d (4 g/serving
for lunch and supper,
which was dissolved in
100 mL drinking water)
Group 2 (The
Almond Skin Group):
almond skin powder, 10 g/d
(5 g/serving for lunch and
supper, which was consumed
after mix into the basic diet)
Group 3 (The
Almond Group):
roasted, unsalted whole
almonds, 56 g/d
(28 g/serving for lunch and
supper, consumed directly),
respectively
Methods: Fecal Sample Collection
Baseline Samples
Week 0: at end of
Run-in Period


Ingestion Samples
Week 1, 3,6: during
treatment
Evacuation Sample
Week 8: at the end of
wash out period
Subjects collected stool samples (10g) in seal specimen cup,
1 specimen cup: weighted into 3 samples (1g) , for
measurement of fecal pH and water content, enumeration of
fecal bacteria, and bacterial enzyme assays
Methods: Measurement of Fecal pH
and Water Content
•Fecal pH Measurement
•1g feces diluted w/DI
•Dispersed by vortexing
•pH measured: lab pH
meter with a proteinresistant electrode (at room
temp)
• Fecal Water Content
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•
1g fecal samples
weighed before and
after drying
Vaccum oven 105
degrees by infrared
moisture gauge
Methods: Enumeration of Fecal
Bacteria
From each fecal sample: 1 g feces mixed with 99 mL sterile H2O, 10-fold dilutions
prepped, 0.1-mL aliquot of each dilution was used to inoculate plates of 4
selective media
1. RaffinoseBifidobacterium
(RB) agar
For enumeration of
Bifidobacterium
spp.
2. lactobacilli
select (LBS) agar
For enumeration of
Lactobacillus spp.,
3. alizarin-βgalactosidase
(ALIZ-GAL) agar
For enumeration of
E. coli
4. sulfite–
polymyxin–
sulfadiazine (SPS
agar ) for
enumeration of
Clostridum
perfringens
After incubation: plates examined for bacterial colonies (colony forming units
CFU) per g wet feces
Methods: Enzyme Assays
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Baseline Week 0 and Ingestion Week 6 Samples used for
determinations of β-galactosidase, β-glucuronidase,
nitroreductase and azoreductase enzyme activities
Samples for Enzyme Assay: 1 g of feces diluted 10-fold in
0.1 M potassium phosphate buffer, homogenized in a blender,
sonicated for 15 min, and centrifuged at 12,000 rpm for
10 min at 4 °C.
Measuring the bacterial enzyme activities: expressed as units
per gram (U/g) of wet feces
Results
Study Subjects: Body Composition, Water Intake,
Defecation- no significant differences
Changes in Fecal Moisture and pH during treatment
period for all subjects: no significant differences except in
control group
Control Group: significant decrease in fecal pH at Week 3
Week 1: fecal samples moister & 4 subjects reported mild diarrhea
Almond Group: water content decreased at week 3 and 6
Microbial Pops in Wet Feces
Microbial Pops in Wet Feces: Bifidobacteria
Bifidobacteria: increased significantly after 6 Weeks of ingesting ALL groups
•
Ingestion Period: (Week 1,3,6) High counts throughout for FOS Control and Almond
Skin
•
Evacuation Period: (Week 8) pops higher than at baseline for ALL groups
•
Almond Group: no significant change until week 6 onward (sign increase observed)
Microbial Pops in Wet Feces: Lactobacillus
Lactobacillus: increased significantly after 6 Weeks of ingesting ALL groups
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FOS and Almond Group: no significant change until week 6 (significant increase
observed)
Ingestion Period: Almond Skin group maintined higher levels throughout
Evacuation Period: remained high for FOS and Almond Skin, but Almond group levels
decreased to initial level
Microbial Pops in Wet Feces: E Coli
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No significant differences during intake of any
Group
Microbial Pops in Wet Feces: C. perfringens
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At Week 6, all groups decreased
Evacuation period: the clostridia populations raised to the baseline
level for all groups
Fecal Bacterial Enzymes
Fecal B-Galactosidase Activities
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FOS and Almond Skin : resulted in a significant increase,
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Almond: increased trend observed
Fecal B-Glucuronidase Activities
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FOS and Almond: decreased trend in activity
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Almond skin: activity decreased significantly
Fecal Nitroreductase Activities
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All groups: significant decrease of activity
FOS Week 6: activity was lower than after almond skin intake or
almond intake
Fecal Azoreductase Activities
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All groups: activity tended to decrease but no statistically
significant differences observed
Discussion: Implication of Results

in the short term, almond
and almond skin bring no
short term significant
changes in body
composition characteristics

the fecal pH and water
content did not change
significantly: fecal pH may
not accurately reflect the
pH in the colon and
depends on absorption of
SCFAs and bicarbonate
secretion
Discussion: Implication of Results
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
almond skins and almonds possess bifidobacteria
and lactobacili stimulation effects
stimulation effects of almond skin and almond
intake on bifidobacteria and lactobacilli were
different
 the
stimulation effect of almond intake was not obvious
until the end of 6 weeks
 eventually (week 6) the pops of bifidobacteria or
lactobacilli in both groups reached a similar level (no
significant difference)
Discussion: Implication of Results

Almond skin or almond ingestion for 6 weeks also
induced a decreasing trend of the viable counts of
C. perfringens
 an
organism known for causing histotoxin and
gastrointestinal diseases in humans
Discussion: Implication of Results

Indicate the stimulation effects of almond skin and
almond intake were typical prebiotic effects
Discussion: Implication of Results
Important Results
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After six weeks of almond skin or almond ingestion, the populations of
Bifidobacterium spp. and Lactobacillus spp. increased significantly
Almond skin or almond ingestion for 6 weeks also induced a decreasing
trend of the viable counts of C. perfringens
the activity of β-galactosidase increased and the activities of βglucuronidase, nitroreductase and azoreductase decreased
Future Implications

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The abundance of dietary fiber and polyphenols
may be associated with the prebiotic effects
observed upon ingestion of almond skins and
almonds.
Further study: explore the specific prebiotic
components in almonds and almond skins
Conclusion
almond skin and almond
ingestion lead to an
improvement of the
intestinal microbiota
profile and modify the
intestinal bacterial
activities
induces the promotion of
health beneficial factors
and inhibition of harmful
factors
almond skins and
almonds possess potential
prebiotic properties
Questions/Comments