Prebiotic effects of almonds and almond skins on intestinal - PowerPoint Presentation

Slide1

Prebiotic effects of almonds and almond skins on intestinal microbiota in healthy adult humans

By: Tess

SoperSlide2

Introduction: Intestinal Microbiota

I

ntestinal

microbiota play an essential role in influencing the health of the hostGood bacteria: Bifidobacterium spp. and Lactobacillus spp.Bad Bacteria: E Coli and C. perfringensSlide3

Introduction: Prebiotics

Use as

functional food ingredients to manipulate the composition of colonic

microbiota in order to improve healthPrebiotic properties: food oligosaccharides and polysaccharides (including dietary fiber) Slide4

Introduction: Almonds

Almond

or almond skin can serve as a candidate food for potential prebiotic

effectsAlmonds: good source of nutrients and amounts of potential prebiotic indigestible carbohydratesAlmond Skins: 4% of the total almond weight Flavonoids in skin: may contribute to the health benefits associated with almond

consumptionSlide5

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 volunteersHypothesis: almonds and almond skins possess potential prebiotic propertiesSlide6

Methods: Subjects

48 subjects (24 male and 24 females)

18-22 years old

Similar living environment in dormsCriteria: good health, nonsmokers, stable weightNo antibiotics/meds 3 months prior to studyNo yogurt or products containing

bifidobacteria

, lactobacilli,

or

prebiotics

in the 3

weeks prior to

the

studySlide7

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), respectivelySlide8

Methods: Fecal Sample Collection

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

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 periodSlide9

Methods: Measurement of Fecal pH and Water Content

Fecal Water Content

1g fecal samples weighed before and after drying

Vaccum oven 105 degrees by infrared moisture gauge

Fecal pH Measurement

1g feces diluted w/DI

Dispersed by

vortexing

pH measured: lab pH meter with a protein-resistant electrode (at room temp)Slide10

Methods: Enumeration of Fecal Bacteria

1.

Raffinose

-Bifidobacterium (RB) agar For enumeration ofBifidobacterium

spp

.

2. lactobacilli

select (LBS)

agar

For

enumeration

of

Lactobacillus

spp.,

3.

alizarin

-β-

galactosidase

(ALIZ-GAL)

agar

For

enumeration

of

E. coli

4. sulfite

–

polymyxin

–sulfadiazine (

SPS agar ) for enumeration of

Clostridum perfringens

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

After incubation: plates examined for bacterial colonies (colony forming units CFU) per g wet fecesSlide11

Methods: Enzyme Assays

Baseline Week 0 and Ingestion Week 6 Samples used for determinations of

β-

galactosidase, β-glucuronidase, nitroreductase and azoreductase enzyme activitiesSamples 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

fecesSlide12

ResultsSlide13

Daily water intake and defecation frequency per week were recorded by the

subjects

All measurements for each parameter at week 0 and week 6 for each group similar

Study Subjects: Body Composition, Water Intake, Defecation- no significant differencesSlide14

Control Group: significant decrease in fecal pH at Week 3 Week 1: fecal samples

moister &

4 subjects reported mild

diarrheaAlmond Group: water content decreased at week 3 and 6Changes in Fecal Moisture and pH during treatment period for all subjects: no significant differences except in control groupSlide15

Microbial Pops in Wet FecesSlide16

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:

BifidobacteriaSlide17

Lactobacillus: increased significantly after 6 Weeks of ingesting ALL groups

FOS

and Almond Group: no significant change until week 6 (significant increase observed)

Ingestion Period: Almond Skin group maintined higher levels throughoutEvacuation Period: remained high for FOS and Almond Skin, but Almond group levels decreased to initial levelMicrobial Pops in Wet Feces: LactobacillusSlide18

No significant differences during intake of any Group

Microbial Pops in Wet Feces:

E ColiSlide19

At Week 6, all groups decreased

E

vacuation period: the

clostridia populations raised to the baseline level for all groupsMicrobial Pops in Wet Feces: C. perfringensSlide20

Fecal Bacterial EnzymesSlide21

FOS and Almond Skin : resulted in a significant

increase,

Almond: increased trend observed

Fecal B-Galactosidase ActivitiesSlide22

FOS and Almond: decreased

trend

in activity

Almond skin: activity decreased significantlyFecal B-Glucuronidase ActivitiesSlide23

All groups:

significant decrease of

activity

FOS Week 6: activity was lower than after almond skin intake or almond intakeFecal Nitroreductase ActivitiesSlide24

All groups: activity

tended to decrease

but no

statistically significant differences observedFecal Azoreductase ActivitiesSlide25

Discussion: Implication of Results

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 secretionin the short term, almond and almond skin bring no short term significant changes in body composition characteristicsSlide26

Discussion: Implication of Results

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

)Slide27

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 humansSlide28

Discussion: Implication of Results

Indicate the

stimulation effects of almond skin and almond intake were typical prebiotic

effectsSlide29

Discussion: Implication of Results

As a result of changes in the intestinal

microbiota

induced by almond or almond skin consumption, the activities of fecal bacterial enzymes changed. increase in β-galactosidase activity: a consequence of elevated populations of bifidobacteria and lactobacilli

decreases

in β-

glucuronidase

,

nitroreductase

and

azoreductase

activities: associated

with the reduction of viable counts of clostridia or other harmful

bacteriaSlide30

Important Results

After six weeks of almond skin or almond ingestion, the populations of

Bifidobacterium

spp. and Lactobacillus spp. increased significantlyAlmond 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 β-

glucuronidase

,

nitroreductase

and

azoreductase

decreasedSlide31

Future Implications

The abundance of dietary fiber and polyphenols may be associated with the prebiotic effects observed upon ingestion of almond skins and almonds.

F

urther study: explore the specific prebiotic components in almonds and almond skinsSlide32

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 propertiesSlide33

Questions/Comments