Presents an overview of the scientific evidence and methods used to prove polydextrose is a safe and effective soluble prebiotic fibre with high toleration
Scientific Validation Of Polydextrose As A Fibre And
1. Scientific Validation of Polydextrose as a Fibre and Sustained Prebiotic for
Digestive Health
Geoff O’Sullivan
Application Manager
September 2007
With contributions from: Prof Glenn Gibson, University of Reading, Dr Nina Rautonen, Dr Artur
Ouwerhand,Dr Kirsti Tiihonen, Dr Helen Mitchell, Dr Oliver Hasselwander and Dr Julian Stowell
2. Scientific Validation of
Polydextrose as a Fibre and Sustained
Prebiotic for Digestive Health
• Rationale for Prebiotics
• Market for Soluble Fibre Ingredients and Prebiotics
• Definition of ‘Prebiotics’
• Scientific Evidence for Existing Prebiotics
• Metabolism and Associated Health Benefits
• Methods for Prebiotic Evaluation
– Colon Simulator
– Quantitative Methods for Specific Bacterial Strains
– Human intervention studies
• Validation of Polydextrose as a Prebiotic
• Linkage analysis
• Future Directions
– New Biomarkers
• Regulatory
– JECFA, FDA and EU
2
3. Probiotics, Prebiotics, synbiotics and fibre
A probiotic is a live microbial food or feed supplement which
beneficially affects the host by improving the balance of
intestinal microflora.
A prebiotic is a nondigestible food ingredient that beneficially
affects the host by selectively stimulating the growth and/or
activity of one or a limited number of bacteria in the colon,
and thus improves host health.
(Gibson and Roberfroid, 1995)
A Synbiotic – is a combination of pro- and prebiotics where
the efficacy of the probiotic is enhanced by the inclusion of a
prebiotic.
Fibre – can be defined in many ways. Physiologically, fibre is
essential to regularize bowel function and it may also
mediate glucose and cholesterol attenuating effects.
3
4. Rationale for Prebiotics – Digestive Diseases
Diseases & disorders include: All digestive diseases – USA
• Abdominal wall hernia
• Constipation Prevalence
• Diverticulitis >75 million by all digestive diseases
(1998) – excluding 135 and 76 million
• Gastritis and non-ulcer dyspepsia non food borne and food borne
• Haemorrhoids infections/illnesses
• Infectious diarrhoea
Mortality
• Irritable bowel syndrome >125,000 including deaths from cancer
• Inflammatory bowel disease (1998)
• Lactose intolerance
Costs
• Peptic ulcer >$86 billion direct medical costs (1998)
• Hepatitis >$20 billion indirect costs (1998)
lost productivity, disability, etc.
Ref: www.niddk.nih.gov/statistics.htm, The Burden of
Selected Digestive Diseases in the USA, 2002, Sandler
et al
4
5. Rationale for Prebiotics – A
Balanced Microflora
• Molecular studies indicate that the intestinal microflora
consists of 1014 microbes from more than 1000 species.
• Little is known about the role played by many of the
dominant bacteria in the gut that are believed to be benign
such as Bacteroides, Eubacterium spp., Ruminococcus spp.,
Butyrovibrio spp.
• Bifidobacteria and lactobacilli are two species with known
positive contributions to human health.
• As the microflora protect against incoming pathogenic
microbes and modulate immune response, a balanced
microflora increases well-being of the gastrointestinal tract.
Prebiotics can contribute to human digestive health by
specifically stimulating growth of bifidobacteria and
lactobacilli, two microbial species accepted to exhibit
Ouwehand AC, Makelainen H, Tiihonen K and Rautonen, N (2006) - Digestive Health, pages 44-51, Part I
Sweeteners and Sugareffects. in Food Technology, Edited by Helen Mitchell, Blackwell Publishing, UK.
beneficial Alternatives
5
6. Definition of ‘A Healthy or Balanced
Microflora’
Cummings JH et al defined a healthy or balance microflora in 2004:
‘A healthy, or balanced, flora is, therefore, one that is predominantly
saccharolytic and comprises significant numbers of bifidobacteria
and lactobacilli. The exact numbers are difficult to give at present
because a proportion of the gut flora have yet to be identified’
Cummings JH, Antoine J-M, Azpiroz F, Bourdet-Sicard R, Brandtzaeg P, Calder PC, Gibson GR, Guarner F,
Isolauri E, Pannemans D, Shortt C, Tuijtelaars S, Watzl B (2004) PASSCLAIM – Gut health and immunity.
Eur J Nutr; 43, Supplement 2:II/118-II/173
6
7. Market – Prebiotic ingredients
Market of Soluble Fibre
World Demand – Volume (KT)
Total: 167KT
Ingredients and Prebiotics
5.6 5.6
12.2 19.7
Fructo-oligosaccharide (FOS)
Inulin
Isomalto-oligosaccharide (IMO)
35.2
36.0 Resistant maltodextrin
Polydextrose
Lactulose
11.2 Resistant Starch
41.5
Others
Others include primarily oligosaccharides that are mainly marketed as prebiotics in
Japan such as soy-oligosaccharides (SOS), galacto-oligosaccharides (GOS), xylo-
oligosaccharides (XOS).
Not all of these compounds meet the criteria for prebiotic classification and some
are at present mainly used as bulking agents.
GIRACT. Soluble Fibre Ingredients. Global Supply/Demand Patterns in Food, Feed &
Supplements. 2004/5-2010 (July 2005).
7
8. Definition “Prebiotics”
The term ‘prebiotic’ was coined by Gibson and Roberfroid in 1995:
‘Prebiotics are non digestible food ingredients that selectively
stimulate a limited number of bacteria in the colon, to improve
host health’
Since then, the concept has been further developed and in order to
qualify for
prebiotic classification, a compound is required:
Gibson GR & Roberfroid MB (1995) Dietary modulation of the human colonic microbiotia:
Introducing the concept of prebiotics. J Nutr; 125:1401-1412
1. to resist gastric acidity, hydrolysis by mammalian enzymes and
gastrointestinal absorption,
2. to be fermented by the gastrointestinal microflora,
3. to stimulate selectively the growth and/or activity of intestinal
bacteria associated with health & wellbeing
Gibson GR et al (2004) Dietary modulation of the human colonic microbiotia:
Updating the concept of prebiotics Nutr Res Rev; 17:259-275
8
9. Metabolism and Associated Health
Benefits
Prebiotic
Prebiotics have
positive effects on Not digested nor absorbed
several biomarkers immune in small intestine
related to health modulation water
benefits. retention
antimicrobial Colonic microbiota
Prebiotics may hence activity biomass
play a role in reducing
the risk of colon cancer,
acetic acid Microbial metabolites
inflammatory bowel increased
disease, gastrointestinal faecal output
infections and in propionic acid butyric acid
sustaining bone health. detoxification
Liver Reduced pH
fat metabolism energy source
cholesterol metabolism improved colonocytes
2+
Ca absorption immune cells
Ouwehand AC, Makelainen H, Tiihonen K and Rautonen, N (2006) - Digestive Health, pages 44-51, Part I
Sweeteners and Sugar Alternatives in Food Technology, Edited by Helen Mitchell, Blackwell Publishing, UK.
9
10. Methods for Prebiotic Evaluation (I)
A) Non-digestibility
• In vitro, by incubation of prebiotic candidate at pH and temperature
conditions of the stomach and incubation with saliva, pancreatic
and small intestinal enzymes and analysis of hydrolysis products.
• In vivo, by measuring recovery of prebiotic candidate in faeces after
oral administration in germ-free rats.
• In vivo, by recovery of at least 90% of the ingested quantity of a
prebiotic candidate the pouch of ileostomised subjects.
B) Fermentation
• In vitro, by studying anaerobic fermentation of the prebiotic
candidate using pure bacterial populations or faecal slurry.
• In vivo, by measuring recovery of prebiotic candidate in faeces after
oral administration in animals or humans and fermentation products
such as gases (CO2, H2, CH4) or short chain fatty acids (acetic,
propionic, butyric and lactic acid).
10
11. Methods for Prebiotic Evaluation (II)
C) Selective stimulation of growth and/or activity of intestinal
bacteria
associated with health & wellbeing
• In vitro, by studying changes in composition of a mixed faecal slurry
before and after fermentation of a prebiotic candidate in a colon
simulator.
• This method is particularly useful for screening of candidate
prebiotics and comparison with established prebiotics.
Final proof that a candidate prebiotic can be classified as prebiotic
has to be obtained in placebo-controlled dietary intervention trials
in humans:
Volunteers are (n= 8-20) are supplemented with prebiotic candidate
(typically 5-15 g/day) for 2-12 days
Stool sampling before and after the intervention to quantify changes in
microflora
Quantification of selectively stimulated growth of bacteria by culture
and and requires culture techniques and nucleotide probe based
Van Loo J (2005) Prebiotics: a nutritional concept gaining momentum in modern nutrition.
techniques
Food Science and Technology Bulletin: Functional Foods; 2:83-100.
11
13. 4 Stage Colon Simulator
N2
+NH 3
N2 N2 N2 N2
+4°C
Fresh +4°C
medium V1 V2 V3 V4 Effluent
3 ml 5 ml 7 ml 9 ml
pH 5.5 pH 6.0 pH 6.5 pH 7.0
“proximal” “distal”
13
14. Quantification Methods for Specific
Bacteria Strains
Method Main Advantages Main Disadvantages
Selective culturing & Inexpensive, allows large Time consuming, operator
identification of biochemical number of replicates subjectivity, only culturable
characterisation bacteria detected
Fluoresence in situ hybridisation Highly specific, also for Time consuming, only probe for
(FISH) unculturable bacteria known bacteria
Percent-G+C profiling Robust method, qualitative Does not distinguish between
picture of the total bacterial specific species
community
Polymerase chain reaction High fidelity and reliability, allows Expensive, time consuming,
(PCR), also quantitative placement of previously some bias during PCR
unidentified bacteria
Direct community analysis Culture-independent, diversity of Some loss of diversity due to
entire sample can be elucidated bias introduced by PCR
Denaturing gradient gel Rapid, also for unculturable Qualitative rather than
electrophoresis (DGGE) bacteria quantitative, loss of diversity due
to bias introduced by PCR
New techniques make use of 16SrRNA oligonucleotide probes which identify specific
bacteria, genera or whole species or sequencing of 16SrRNA amplified by PCR.
Van Loo J (2005) Food Science and Technology Bulletin: Functional Foods; 2:83-100.
14
15. Polydextrose - Chemical Structure
Randomly cross linked polymer of glucose. R
can be hydrogen, sorbitol-bridge or more
CH2OH polydextrose
CH2OH
O
O OH
OH O
O CH2
HO CH2OH
HO O CH2
OH O
OH O CH2 O
O CH2
CH2OH HO O OH O CH2
HO O
O OH OH O O
OH OH OR
OH O OH OH O
HO HO
HO OH HO
OH
OH CH2OH
CH2OH O Highly branched
All bonds are present O OH O
complex 3D
OH O
1 – 6 and 1 – 4
OH structure
HO
Linkages
OH
15
16. Polydextrose - Chemical Structure
• The Molecular size of polydextrose is limited to an
average of 12 DP units with a molecular weight range 180 –
5000
• Polydextrose is a randomly bonded condensation polymer
of D-glucose with some bound sorbitol and a suitable acid
• For starch the range of DP is typically from 37 – 49
• Polydextrose - has the highest amount of branching
and complexity of any carbohydrate
16
17. Polydextrose Caloric Utilization
• Structural compactness and complexity prevents
hydrolysis by mammalian enzymes
• Large intestinal microorganisms only capable of partial
conversation
Large Intestine Volatile Fatty acids 1 kcal/g
• Radio-tracer studies in rats and humans confirm energy
value(1).
• Other studies have confirmed this value(2) (3)etc.
1. Archour L, Flourie B, Briet F, Pellier P, Marteau P and Rambaud J-C (1994) Gastrointestinal effects and energy value
of polydextrose in healthy non obese men. American Journal of Clinical Nutrition: 59: 1362-1368
2. Figdor SK and Rennhard HH (1981) Caloric utilization and disposition of [14C]polydextrose in the rat. Journal of
Agricultural and Food Chemistry: 29(6):1181-9
17
18. What is an effective prebiotic?
A product that:
• Increases the overall wellbeing of
gastrointestinal tract
• Decreases risk of gastrointestinal
diseases
• Is safe!
• Increases saccharolytic fermentation
and reduces
putrefactive fermentation
18
19. Metabolism of polydextrose in the different
Stages of a colon simulator
• Polydextrose is 16
fermented gradually
Total concn of PDX mg/ml
14
but not completely
throughout the four 12
stages
10
•The complex 8
structure may
explain gradual 6
fermentation
4
2
Fava F, Mäkivuokko H,
Siljander-Rasi H, 0
Putaala H, Tiihonen K,
Stowell J, V1 V2 V3 V4 V1 V2 V3 V4 V1 V2 V3 V4
Touhy K, Gibson G
and Rautonen N
0.5% PDX 1.0% PDX 2.0% PDX
(2007) British Journal of
19
Nutrition 98, 123-133
21. Polydextrose - Sustained Fermentation in
the Colon
Fermentation continues also in the distal colon with Polydextrose
Fatty acid production using a 4-stage fermentation simulation
70
60
50
40 Butyric acid
mM
Propionic acid
30 Acetic acid
20
10
0
Stage 1 Stage 2 Stage 3 Stage 4
“proximal” “distal”
21
Source: unpublished data - Danisco
22. Volatile Fatty Acids
6
5 **
Stool content (mg/g)
0 g/d
4 * p<0.05, ** p<0.01 for
4 g/d
3
comparison of results to
8 g/d
** 12 g/d
baseline (0 g/d)
2
** ** Zhong Jie et al., American Journal of
1
Clinical Nutrition (2000)
0
Acetate Propionate Butyrate Iso- Iso-
*
butyrate valerate
Source: unpublished data
Polydextrose is fermented in the colon producing short chain fatty acids (butyrate,
isobutyrate, acetate), which decrease pH
Faecal pH decrease can suppress production of enteric toxins
22 Increased butyrate promotes the growth of colonic cells (source of energy)
23. Prebiotic Effect
7
0 g/d
6
4 g/d
Counts (x109/g stool)
5 8 g/d
4
12 g/d Good bacteria - increasing
3
2
1
0
B. fragilis B. vulgatus B. intermedius Lactobacillus Bifidobacterium
Bad Bacteria - decreasing
Very large increase of beneficial Lactobacillus and Bifidus and a resulting decrease in
toxic bacterias
Zhong et al., American Journal of Clinical Nutrition Vol 72. No 3 September 2000
23
24. Polydextrose fermentation does not result in
the accumulation of lactic acid in vivo
Polydextrose does not Residual lactic acid concentration in rats
increase residual lactic acid
5
concentrations in the lower 4.5
intestine (p-value for 4
3.5
difference > 0.10). (Hollie M. 3
mmol/g
Probert,1* Juha H. A. Apajalahti,2 2.5
Nina Rautonen,2 Julian Stowell,3 and 2
1.5
Glenn R. Gibson1, Applied and
1
Environmental Microbiology, August 2004,
0.5
p. 4505-4511, Vol. 70, No. 8) 0
Low -fibre Western diet + 2%2% Litesse of diet
+ polydextrose
24
25. Adverse effects
• Ammonia, biogenic amines, indoles and phenols are
produced in putrefaction. They are toxic in large quantities.
(Cummings and Macfarlane 1991(9) , Smith and Macfarlane, 1997 (10) )
• Branched volatile fatty acids, such as isovaleric, isobutyric
and 2-methylbutyric acid, are also produced in putrefaction.
They are not toxic but serve as biomarkers for harmful
putrefaction.
(Bergman 1990 (11), Cummings and Macfarlane 1991 (9), Ito
et al. 1993 (12),
Smith and Macfarlane 1997 (10) )
25
26. Production of branched fatty acids is decreased
by polydextrose in rats
Concentrations of residual branched fatty acids in the rat lower
intestine after 4 weeks
Polydextrose reduces
Caecal concentration of branched VFAs
putrefaction in rat
lower GI tract in 1.2
Western low fiber diet 1
(p < 0.0001 ****).
0.8
mmol/g
0.6
0.4
0.2
0
Low-fibre Western diet + 2% Polydextrose
2% Litesse of diet
Source: unpublished data
26
27. Faecal concentrations of branched fatty acids
are decreased by polydextrose in humans
In a clinical trial Faecal concentrations of branched VFAs
polydextrose
Concentration of branched VFAs (mmol/g) 5
reduced faecal
4.5
branched fatty
4
acids (p=0.04* 3.5
from 0 to 3 3
weeks and 2.5
Control (normal diet)
Polydextrose (10g/day)
Litesse (10 g/day)
p=0.004 ** 2
from 0 to 6 1.5
weeks). 1
0.5
0
0 wk 3 wk 6 wk
Source: unpublished data - Danisco
27
28. Fast- and slow-fermenting prebiotics in the colon
1st generation
prebiotics increase
fermentation in the
proximal colon.
Fast-fermenting prebiotics
1st generation
Fermentation of
Polydextrose polydextrose
continues still in
the distal parts.
Proximal colon Distal colon
28
29. Rapidly fermented prebiotic leading to
Putrefaction
Butyrate not produced
in distal colon
Prebiotic Number of bacteria
putrefaction
Saccharolytic fermentation
Putrefaction is
associated with
health risks
Proximal colon Distal colon
29
30. Sustained saccharolytic fermentation
Butyrate production throughout the colon
Fermentation
Prebiotic Number of bacteria
Saccharolytic fermentation
putrefaction
Proximal colon Distal colon
30
31. Polydextrose supplementation to normal Western
diet leads to sustained fermentation in the colon
Stomach/Small intestine Large intestine
proximal distal
Fermentation
Digestion Non-absorbed
& Steady rate Steady rate
Food Faeces
Absorption material
Fat / Monosaccharides /
Amino acids
Steady production of short chain fatty acids,
no uncomfortable rapid gas formation!
31
32. Enhancing and inhibiting effects of polydextrose
Saccharolytic Putrefactive
Lactic Acetic Butyric ACIDS Branched Phenols
indoles
Faecal mass Energy for
epithelial and
immune cells Amines etc. BASES Ammonia
SHORTER Control of
TRANSIT TIME proliferation
Anti-
Down pH Up
bacterials
REDUCTION OF ENHANCED
PATHOGEN
COLON CANCER MINERAL
REDUCTION TOXIC EFFECTS
RISK ABSORPTION
32
33. Polydextrose a typical DP 12 structure
Terminal Group 1-6
OH HO
O OH
HO O OH
HO
OH O
HO
O O
HO
HO
O
OH OH
HO O OH
HO
Double substituted groups O
O O
HO O
O HO O
OH
O O
O OH HO
HO OH
HO O
O OH
HO O
HO HO O
O HO
HO OH HO
OH O
O OH OH
OH
HO
HO
OH
Fully substituted Core
Source: unpublished data All bonds 1-6,4,3,2
33
34. Polydextrose before and after colon simulator
MALDI of Colon Simulator Sample vs. Regular Polydextrose
Colon Simulator Sample
Regular Polydextrose
Relative Peak Height
2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27
Degree of Polymerization
Source: unpublished data
34
35. Preliminary Linkages and Branching
Branching and Linkage Normalized Linkage Positions for 3%
Polydextrose in Colon Simulator Vessels 1, 2, and 3
60 Litesse Vessel 1
Terminal groups decrease
Vessel 2 Vessel 3
50
Core material increases
40
Area %
30
20
10
0
al
ch
ch
ch
d
d
d
d
d
he
ke
ke
ke
ke
in
an
an
an
rm
l in
l in
l in
l in
nc
br
br
br
te
ra
6-
4-
3-
2-
le
le
le
nb
ub
ng
ip
no
tr
do
si
Type of Linkage or Branching
35
Source: unpublished data
36. Polydextrose - Prebiotic Summary
• Prebiotic
– 4 – 12 g of Ploydextrose,
Zhong et al, American Journal of Clinical
Nutrition (2000), vol 72 pp. 1503 –9
– Promote growth of intestinal Lactobacillus and
bifidus
– Fermentation in the large intestine yields short-
chain fatty acids (including butyrate)
– Improved gastrointestinal function , no adverse
effects
Prebiotic
36
37. Polydextrose - Mineral Absorption
• Improvement of mineral absorption
– dietary polydextrose (5%) increased calcium
absorption and bone mineralisation in rats
– 21 days increased the bone calcium concentration and
apparent calcium absorption when compared to control
– polydextrose has the potential to increase calcium in
humans, linked to intestinal acidification, but unknown
mechanisms are also involved
Ref: Hara, H et al. Ingestion of the soluble dietary fibre,
polydextrose, increases calcium absoption an bone
mineralization in normal and total-gastrectomized rats. British
Journal of Nutrition, 200, 84:655-611
37
37
38. Definition – Dietary Fibre
Fibre definition according to the CODEX alimentarius:
Dietary fibre means carbohydrate polymers with a degree of polymerisation (DP)
not lower than 3, which are neither digested nor absorbed in the small intestine. A
degree of polymerisation not lower than 3 is intended to exclude mono- and
disaccharides. It is not intended to reflect the average DP of a mixture.’
CODEX alimentarius. Document CL 2005/53 - FSDU Dec 2005.
38
39. Polydextrose - Soluble Dietary Fibre
• Soluble fibre
– Dietary fibre is difficult to define - can use analysis, Analysis :
physiology, chemistry or origin Growing acceptance
of physiological definition AOAC 2000.11
– Fifteen clinical studies show physiological benefits
from Litesse
• Fecal • Serum
– Bulking (increase) – Glucose (attenuate)
– Softening (increase) – Lipids (attenuate)
– Transit time (decrease)
– Flora, i.e. prebiotic • Intestinal
(improve) – Physiology
– pH (decrease) (growth)
– Short Chain Fatty Acid
(increase)
– Carcinogens (decrease)
39
42. Studies on the effects of Polydextrose intake on
gastrointestinal function
• 120 subjects divided into four Laxative threshold for Litesse is 90
groups: g/day (Burdock and Flamm 1999)
– 0, 4, 8 and 12 g Litesse/day for four
weeks
Decreased pH enhances mineral
• Improvement in colon function absorption and inhibits acid sensitive
• No laxation problems pathogens (Hara et al., 2000)
• Decrease in faecal pH
• Increase in faecal weight
• Increase in SCFAs, especially
butyrate
• Increase in Lactobacillus and
Bifidobacterium (traditional method)
42 Zhong et al., 2000,
43. ZHONG JIE et al - AJCN, 2000 72: 1503-9
ZHONG JIE et al - AJCN, 2000 72: 1503-9
7
0 g/d
6
4 g/d
Counts (x109/g stool)
5 8 g/d
4
12 g/d Good bacteria - increasing
3
2
1
0
B. fragilis B. vulgatus B. intermedius Lactobacillus Bifidobacterium
Bad Bacteria - decreasing
Very large increase of beneficial Lactobacillus and Bifidus and a resulting decrease in
toxic bacterias
Zhong et al., American Journal of Clinical Nutrition Vol 72. No 3 September 2000
43
44. DIGESTIVE HEALTH - DELIVERABLES
• Regularizing bowel function/laxation
• Reduced inflammation/allergic reactions
• Enhanced immune system
• Increased saccharolytic bacteria
• Reduced colonic pH discouraging growth of putrefactive bacteria
• Lower risk of pathogens
• Reduced production of toxic products e.g. ammonia, phenolics
• Reduced cholesterol
• Improved glycaemic control
• Reduced risk of diabetes, cardiovascular disease etc
• Increased butyrate production:
- Improves integrity of the gastric mucosa
- Programmed death of cancer cells – apoptosis
• Reduced cancer risk – especially colon cancer
• Enhanced mineral absorption - Reduced risk of osteoporosis
44
45. Modulation of Epithelial Gene Expression
Using Prebiotics
Aim: In vitro evidence of anti-inflammatory and anti-carcinogenic properties
• An ”immortal” human colon cancer
cell line
• A good model of intestinal epithelial
cells
• Caco-2 cells are exposed to different
treatments and the effects on gene
expression are measured
health-promoting treatments can be identified by a “good” effect on gene
expression
45
46. The Genes of Interest: Cyclooxygenases
Membrane phospholipids
phospholipase A2
• Two cyclooxygenase
(Cox) genes code for Arachidonic acid
the Cox-1 and Cox-2 cox-1 cox-2
proteins.
• Mainly inducible,
Prostaglandin H2 e.g.
• Cox-1 and –2 inflammatory
cytokines or LPS
synthesize
prostaglandins
prostaglandin
synthases
PGI2 PGD2 PGE2 PGF2
46
47. The Roles of Cox-1 and Cox-2 in Health
and Disease
• Cox-1
– expressed all the time
– essential to normal tissue function and repair; the ”good” Cox.
– inhibition of Cox-1 is the reason for the toxic side effects (bleeding)
of NSAID’s (e.g. aspirin)
• Cox-2
– inducible in most tissues, including the gastrointestinal tract
– equally important as Cox-1
– overexpression is associated with (or is a triggering event in) various
inflammatory and malignant diseases; the ”bad” Cox
– Cox-2 inhibitors have a chemopreventive effect
47
48. Prebiotics as Modulators of Epithelial
Cox-gene Expression
Supernatants from polydextrose fed simulation
model were obtained from the different stages of colonic
the simulator and applied to Caco-2 cells. fermentation
Cells were then exposed for 24 hrs prior to
isolating the RNA.
Soluble metabolites
One possible mechanism could
be that microbial metabolites
affect epithelial
cyclooxygenase expression
epithelial
cell
function
48
49. Caco-2 cell-based simulation method
1. Cell exposure for 24 hours 2. RNA purification
3. RNA measurement by quantitative RT-PCR
- Cyclooxygenase-2 expression was determined
49
50. Polydextrose normalizes Cox-2
expression in Caco-2 cells
• Polydextrose fermentation in
the proximal colon does not
Expression of cox-2
influence cox-2 expression
Relative expression at 24h
1,80 No fiber 1 % Polydextrose 2% Polydextrose
• Expression of cox-2 is
decreased in the more distal 1,60
colon, in vessels 2-4 1,40
1,20
• This implies that pdx can
1,00
reduce risk for inflammation
0,80
and carcinogenecity in the 0,60
distal colon by reducing cox-2 0,40
gene activity 0,20
• Reduction of risk for colon 0,00
cancer development has also
0% a te
M
0% x 1
0% x 2
0% x 3
1% x 4
1% x 1
1% x 2
1% x 3
2% x 4
2% x 1
2% x 2
2% x 3
x4
been observed in animal
Na DME
pd
pd
pd
pd
pd
pd
pd
pd
pd
pd
pd
pd
r
uty
models (Ishizuka S et al.
-B
2003 Nutr Res 23, 117-122)
50
51. Main Conclusions from Colon
Simulator Studies
• Two in vitro techniques have been combined in order to study fermentation
of prebiotics and interaction with gut mucosal cells in more detail
• The results provide a hypothesis of how a prebiotic, specifically
polydextrose, can influence mucosal gene expression beneficially via colon
fermentation reducing risk for for colon inflammation and cancer development
• These novel tools can be used e.g. to gain more insight to the structure-
function relationship of prebiotics and to characterize further the role of gut
microbes on colon health
51
52. Polydextrose as an effective prebiotic -
Summary
• Passes intact to the colon
• Fermented throughout the colon - increasing saccharolytic fermentation (reduces pH)
• Stimulates Bifidobacteria
• Enhances butyrate production
• Does not cause acidosis (no accumulation of lactic acid)
• By competition, reduces putrefactive fermentation (less branched VFAs, less biogenic amines
– reduced cancer risk)
• Enhances mineral absorption
• Stimulates immune system without causing inflammation
• Reduces inflammation – Dose dependent reduction in COX 2 expression
• Well tolerated
• Soluble fibre effects
• Good stability and versatility in foods
52
53. Reduced Colon Cancer Risk
Substantial evidence from animal studies
• Reduced tumour incidence in models where cancer inducing
chemicals mimic the effect of toxic metabolites of food components
• Anti-cancer properties also observed in genetic pre-determined
models such as apc min mouse (protective gene switched off)
• Anti-cancer effects demonstrated in tumour implantation models
where advanced states of cancers are studied
• Possible mechanisms:
- Suppression of DNA damage and increased repair
- Stimulation of apoptosis in colon
(Van Loo J (2005) Food Science and Technology Bulletin: Functional Foods; 2:83-100. Van Loo J and Jonkers N (2001) Nutr Metab Cardiovasc Dis;
11,Suppl to No 4:87-93)
Based on the data from experimental data, a EU funded research
project: the SYNCAN project QLK1-1999-00346 was initiated to
evaluate whether a combination of pre- and probiotics may reduce
the risk of colon cancer in humans.
53
54. Bifidogenic Activity in Humans (II)
Study design
• 22 young adults (15 female/ 5 male)
• Polydextrose: 5 g/day Results: Probiotic mixture
supplemented with polydextrose
• probiotic mixture:
increased cultured bifidobacteria
Lactobacillus GG, L. rhamnosus
LC705, Propionibacterium shermannii
Period Mean S.D. p
JS and Bifidobacterium breve Bbi
Run-in 7,0 2,2 NS
• Fecal sampling after each two-week
Probiotic 7,6 2,0 NS
periods: run-in, probiotic mixture,
PDX+Probiotic 8,9 2,5 <.001
probiotic mixture supplemented with
polydextrose (5 g/day) and wash-out Follow-up 8,5 1,5 <0.05
• total counts of bifidobacteria were Results shown as log10. Statistical significance to run-in with
measured by plating pairwise t-test. Detection limit = 3 log10.
Only the mixture of Litesse® Polydextrose with probiotics increased bifodo count
significantly.
54
Tiihonen et al (2007) in press.
55. Reduction of Aberrant Crypt Foci by Ingestion
of Polydextrose (PDX) in the Rat Colorectum
day
-7 0 1 7 35
Fiber-free x
PDX-A x
PDX-B x
PDX-C x
PDX-D x
x = DMH injection
= PDX feeding
PDX administration is most
effective against
90 1,2-dimethylhydrazine (DMH)
80 induced aberrant crypt foci
70 (ACF) when feeding starts
Number of ACF
60
*p < 0.05, N = 7
one week prior to
50 DHM injection
40 *
30 PDX may play a role in the
20 prevention of colon
10 carcinogenesis.
0
Fiber-free PDX-A PDX-B PDX-C PDX-D
Ishizuka et al (2003) Nutr Res 23:117-122.
55
56. Polydextrose – Approval Information
The FAO/WHO’s Joint Expert Committee on Food
Additives (JECFA) review of a food additive is often
regarded as the final word in the independent safety
assessment of any particular substance
Polydextrose was evaluated by JECFA at its 31st
meeting in 1986
Following this review they gave polydextrose an ADI
of "Not Specified", which represents the safest category
into which JECFA are able to place a food additive
(JECFA) Joint FAO/WHO Expert Committee on Food and Additives
(FAO) Food and Aricultural Orgainisation of the United Nations
56
57. Polydextrose – Approval Information
Burdock and Flamm (1999)
This is a very comprehensive review of the data that
was submitted to the US FDA in the original Food
Additive Petition for the approval of polydextrose as a
food additive
The safety of polydextrose was also affirmed by the US
FDA via the publication of 21 CFR 172.841 permitting
the use of polydextrose in a wide variety of applications
following the GMP/Quantum satis principle
(e.g. no numerical limit on use)
The review on toleration (Flood, Auerbach and Craig)
also discusses some of the relevant studies
Flood, MT, Auerbach, MH and Craig, SAS (2004)
A review of the clinical toleration studies of polydextrose
in food. Food and Chemical Toxicology 42: 1531-1542
57
57
59. Polydextrose – Approval Information
European Commission Scientific Committee for
Food
(EC SCF) in 1990, who following a full review of the
safety, toxicological and tolerance data available,
approved polydextrose as a bulking agent for use in
foods at Quantum satis (e.g. it can be used at GMP
levels, without numerical limit)
Polydextrose was subsequently approved for use at
Quantum satis in food under Annex I of the
Miscellaneous Additives Directive
(which represents the broadest use category for
food additives within the EU
Polydextrose has been on the market for many years
and has a history of safe use, and that production of
polydextrose is conducted under the strictest principles
of HACCP, and follows ISO standard 9001:2000
59
59
60. Polydextrose Gastrointestinal
Toleration
Tolerance Threshold for Sugar Substitutes in
Non-adapted Adults and Children (figures in brackets)
Substance Single Dose (g) Daily Dose (g)
Fructose 70 >90
Mannitol 10 -20
Sorbitol 20 (10) 50 (30)
Xylitol 20 (10) 50 (30)
Lactitol 25 40
Maltitol 30 50
Isomalt 30 (20) 50 (45)
Polydextrose 50 90 (20)
R Grossklaus (1990) Gesundheitliche Bewertung der Risiken durch Lebensmittelzusatzstoffe am Beispiel der
Zuckeraustauschstoffe, Bundesgesundsheitsblatt 12/90 (Safety evaluation of the risks from food additives by examples of
sugar substitutes)
60
61. Polydextrose Gastrointestinal
Toleration
• Polydextrose has low caloric utilisation because it is poorly digested
• Because it is poorly digested, excessive consumption can cause laxation
symptoms in sensitive individuals
• Because laxation is an osmotic effect, and polydextrose has higher molecular
weight than the polyols, polydextrose has a higher laxation threshold than the
polyols
• Polydextrose laxation threshold is comparable in adults and children
No laxation dose in g (g/kg bw/day)
Adults 50 (0.7)
Children 20 (1.0)
• JECFA, 1987: “Studies in man have demonstrated that polydextrose, when
administered at very high doses, exert a laxative effect, with a mean laxation
threshold of 90g per day or 50g as a single dose”
• EC/SCF, 1990: “Large doses of polydextrose exert a laxative effect with a mean
laxative threshold of 90g per day or 50g as a single dose
61
62. Polydextrose Gastrointestinal
Toleration
Pfizer Studies: Clinical Toleration Studies of Polydextrose
Investigator Site Year No of Subjects Duration Highest Dose g Diarrhoea
single/daily Episodes
Alter Pfizer 1974 20 male adults 3 weeks 50 / 150 11pdx;5placebo
Knirsch Pfizer 1974 57 male adults 10 days 24/79 2 at 35g/day
McMahon Tulane Univ. 1974 10 type 2 diabetics Single dose 50/50 4pdx;2glucose
Raphan a Pfizer 1975 21 adults –11M/10F 10 days 43/130 none
Raphan b Pfizer 1975 51 adults – 31M/20F 12 weeks 20/60 1@45+60g/day
Bunde Hill Top Res. 1975 11 children 2-3yrs 6 weeks 10/15 4@15g/day
1975 11 children 4-6 yrs 6 weeks 10/20 1@20g/day
1975 12 children 7-9 yrs 6 weeks 15/30 1@30g/day
1975 12 children 10-12 yrs 6 weeks 15/40 4@20g/day
1975 12 children 13-16 yrs 6 weeks 20/55 1@30+55g/day
Scrimshaw & MIT 1977 16 adults – 11M/5F 8 weeks 20/50 none
Young
Beer Univ TX 1989 24 male adults Single dose 58/58 none
Curtis Harris Labs 1990 200 female adults Single dose 40/40 none
62
63. Polydextrose Approvals
(Total 57 Countries – 23/08/2007 )
Europe, Middle East, Africa
Austria Belgium (7/88)* Czech Rep’ (2/96) LEGEND:
Denmark Egypt* Finland
France* Germany* Gibraltar Bold Face: polydextrose can
Greece (5/95) Hungary Iceland be sold
Ireland Israel Italy 5
Italics: Reduced citric acid catalysis OK
Luxembourg5 Netherlands1 Norway1*
Poland (7/94)* Portugal5 Saudi Arabia Underline: Phosphoric acid catalysis OK
Slovakia South Africa Spain5
Sweden1 Switzerland Turkey * Can be labeled dietary fiber
United Arab Emirates United Kingdom*1 Croatia 1.Specific diabetic endorsement
Asia, Americas, Others 2. Laxation label statement required
Argentina2 (3/93)* Australia*1,2 Brazil* (may have usage trigger)
Cambodia Canada Chile
PR China (10/93)2* Colombia Costa Rica 3. Commercially accepted and
El Salvador Guatemala Honduras sold but not formally approved
Hong Kong Indonesia Japan3,4*
Korea (7/89)* Malaysia Mexico* 4. Classified as food, not food
New Zealand* (10/84) Peru Philippines3 additive
5. Approved via EU MAD, not individual
Singapore* Taiwan2* Thailand member state legislation
United States2 * Uruguay Venezuela
63
64. Regulation on Health claims
Regulatory situation in Europe, principles
• Today there is no regulation on health claims in
Europe and
the situation is very different from country to
country .
• European commission wants an harmonisation
of the conditions of use for Nutrition and
Health claims in Europe.
– Adoption and implementation within proposed
time frame
• Claims will be related to the products for end
consumer
• All claims used will have to be authorised in
advance*
* Various transition measures concerning products launched on the market before the implementation of the
new regulation
64
65. Procedure for "Articles 13 HEALTH
claims"
January 2007
Application Procedure Submission to EFSA
Evaluation by
Commission
Member State authority EFSA Commission
January 30th, 2008
or CIAA List '2years
Standing Cte opinion Commission
Draft decision
Final decision
The Commission shall adopt
a positive list of claims within 3 years = 2010
65
66. Scientific Validation of Polydextrose as a Fibre and Sustained Prebiotic for
Digestive Health
Geoff O’Sullivan
Application Manager
September 2007
With contributions from: Prof Glenn Gibson, University of Reading, Dr Nina Rautonen, Dr Artur
Ouwerhand,Dr Kirsti Tiihonen, Dr Helen Mitchell, Dr Oliver Hasselwander and Dr Julian Stowell
