The Science of Nutrition
= The Art of Caring
Dr. Sanaa Youssef
MD Pediatrics
24-9-2010
Goals of This Talk
 Understanding Updates about
the Rediscovery of the Human GIT
 Highlighting the importance and function
New Emerging Ingredients
(PRObiotics – PREbiotics)
 My audience will STILL be AWAKE
by the end of the talk.
The Rediscovery of the
INNER TUBE OF LIFE
the Human GIT
INNER TUBE OF LIFE
 The intestine is an extremely complex system that
participates in protection of the host through strong defense
mechanisms from the external environment;
 Defense task is based on three compartments that are in
permanent contact and dialogue with each other:
1- The ecological barrier (normal inhabitant flora within intestine)
2- Mechanical barrier (mucous epithelia)
3- Immune barrier (GALT, secretory IgA, intraepithelial lymphocytes,
macrophages, neutrophils, natural killer cells, Payer’s nodes and mesenteric
lymph node) (Mohajer, 2000)
Our Intestine = 400 square meter surface…
i.e. the surface area of a tennis court
INNER TUBE OF LIFE
Historical Facts
 The colon Is a part of the body's digestive
system (about six feet long) that moves waste material
from the small intestine to the rectum.
Little was known about colonic functions.
Many thought that the colon was a colander that
strained the feces.
Later Accepted ROLES about colonic functions :
Conservation of water and electrolytes
Control evacuation of faeces
INNER TUBE OF LIFE
Advances in understanding
Colonic function
 Recent researches demonstrated the importance of
the colon as a metabolic organ with an influence
on overall metabolism, an effect that is attributed to
activity of Microflora the role of which was
Underestimated.
 New studies revealed:
 The role played by microbiota in the colon.
 Functions of different mucosal epithelial cells of the
colon.(Immunocompetent cells)
 The mucosal hydrophobicity of the colon.(A
2000;46:515-521 doi:10.1136/gut.46.4.515 )
Lugea et al,Gut
Did you know that in the
“COLON World”….!!!??
Battles are Fought,
Helpful Substances are
Manufactured,
& The immune system is
Bolstered.
Where “Man Meets Microbe”
A Dynamic Interplay
 Trillions living bacteria exist in the human intestine
 We have more bacteria in our bodies (10 times greater)
than the total number of our somatic and germ cells
 We carry about 2 kg of bacteria !!!!!!!!
 Over 500 species of bacteria present in human colon.
 Lactobacillus Bifidis and Acidophilus comprise the
majority of healthy bacteria in the colon along with other
disease producing bacteria.
Where “Man Meets Microbe”
A Dynamic Interplay
1- Short Transient Time
2- Bile milieu
3- Pancreatic secretion
4- ph = 7 (neutral)
HCL
Mucous, cells…..
Prevents
bacterial reflux
Ileo-ceocal valve
Where “Man Meets Microbe”
A Dynamic Interplay
Our gut Microbiota can
be pictured as a
MICROBIAL ORGAN
placed within a host
organ
“The intestine is not only a
digestive absorptive organ but it is the
largest immune organ
in our body.”
 The very rapidly developing immune system begins from
birth up to 2 years.
 It starts with creating a healthy digestive system which
plays a major role from infancy and throughout all our life
(about 80% of our immune system is found in the GIT)
“ This
immature immune system
needs special measures for its
Protection and Support.”
Sharing My Secrets of Health
Early In Life ???
 The gastrointestinal tract of a normal fetus is sterile.
 During the birth process: the aseptic or sterile, digestive tract of
the fetus is inoculated with bacteria (proximity of the birth
canal and the anus).
 Rapidly thereafter, effective methods of ensuring transmission
of microbes to the sterile GIT:
o parental expression of neonatal care: suckling, kissing and
caressing (mother’s flora)
o Genetic factor
o surrounding environment
o Feeding pattern: the first biggest challenge is one the
intestine becomes inhabited by microbes which are
characterized by instability and fragility.
Later the microbiota will stabilize according to the type of
feeding.
Early In Life ???
 The first colonization of the intestine is one of the most
profound immunological exposures faced by the newborn
infant (during the first days of life).
 The next great changes in the composition of the intestinal
microbiota come with the introduction of solid food and
weaning (Favier et al., 2002).
 Hygiene Hypothesis: Decreased bacterial stimulation
during infancy and childhood is asscociated with slower
postnatal development and delayed maturation of the
immune system. (L.E.M. Niers et al., 2005)
 Relatively small changes will take place by after years of
age where the child will have an adult-like microbiota and
then it remains practically unchanged (Zoetendal et al., 2008).
New Perspective
In INFANT NUTRITION
New emerging dietary
ingredients
 Probiotics and Prebiotics share a unique role
in human nutrition.
 Research has shown that Probiotics and
Prebiotics are useful in achieving positive
health effects and well being to the host.
PRObiotics
“LIVE” microorganisms which confer health
benefits on the host”, when administered in
adequate amounts. (Marco ML et al,2006)
 Probiotic is not a synonym for native beneficial bacteria,
although they may be isolated from this source.
 They should be identified by genus, species and when
appropriate by strain when supplemented.
The term “probiotic,” by definition, can
never be used to describe products
comprised primarily of Dead Bacteria.
(Journal of the American Dietetic Assosciatio,2008)
PRObiotics
 Probiotics are sensitive in a strain-dependent manner
to environmental exposures such as heat, moisture,
oxygen, and acid. Once the package is opened, these
barriers are compromised.
 The doses should reflect any losses inherent to the
probiotic as it moves through the alimentary canal.
When wishing to deliver their benefits (Immune
enhancement) dose should be adjusted according to
the strain and better increased level of the Probiotic
should be considered because of the losses.
(Journal of the American Dietetic Assosciatio,2008)
PRObiotics
• They Only Transiently colonize the Gut and do not
typically become part of the permanent resident micro
flora of the host.
NO Statement
should generally refer to
Probiotics as “Efficacious or Safe”;
this would be as inappropriate as stating
Antibiotics in general are “Efficacious and Safe”.
(Journal of the American Dietetic Assosciatio,2008)
PREbiotics
 The term prebiotic was introduced by Gibson and Roberfroid 1995
who exchanged “PRO" for “PRE" which means “Before“.
‘A prebiotic is a selectively fermented ingredient that
allows specific changes, both in the composition and ⁄
or activity in the gastrointestinal microbiota that confers
benefits upon host well-being and health.’(Gibson et al.,
2004)
“Nutriceuticals” or “Biotherapeutics” or
“Prebiotics”
= substances or supplements administered
to obtain nutraceutical effects that extend
“beyond those of regular nutrition.”
(Journal of the American Dietetic Assosciatio,2008)
Facts about PREbiotics
 Prebiotics; are simply speaking the preferential
“FOOD” for Friendly Beneficial Bacteria
colonizing the digestive tract.
“colonic food”
 They are dietary supplements that play a role in
Balancing the Intestinal Mucosal Immune
System in newborns and children.
Criteria for eligibility as PREbiotic
(Gibson et al., 2007)
1) Resistance to gastric acidity, to hydrolysis by
mammalian enzymes, and to gastrointestinal
absorption;
2) Selective stimulation of the growth and/or activity
of those intestinal bacteria that contribute to health
and well-being
3) Fermentation by intestinal microflora; to produce
SCFA & gas.
4) Induce LUMINAL or SYSTEMIC beneficial
effects.
Established PREbiotics
Breast Milk oligosaccharides Original they represent the
third largest component of Human Milk 20 - 23 gm/l in colostrum &
12- 14 gm/ in mature milk.
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Polydextrose – Fructans
Inulin Wheat, banana, onions, garlic, leek, chicory.
FOS (Fructo-oligosaccharides or oligofructose) plants.
GOS (Galacto-oligosaccharides) milk.
(also known as TOS – trans-galacto-oligosaccharides)
Lactulose - Lactosucrose
SOS (soy-oligosaccharides)
XOS (xylo-oligosaccharides)
IMO (isomalto-oligosaccharides) corn & wheat.
Lactitol
(Journal of the American Dietetic Assosciatio,2008)
SyMbiosis
SyMbiosis
Symbiosis
(Greek: syM "with"; & biosis "living")
 The term was first used in 1879 by the German mycologist
Heinrich Anton de Bary, who defined it as "the living together
of unlike organisms.“
 Commensalism is a class of relationship between two
organisms
There are two associations:
 Mutualism: (facultative) both organisms benefit
 Parasitism: (obligate) one organism benefits and the
other one is harmed.
SyMbiosis
“Intestinal Microbiota
is an example of
A symbiotic relationship
with the host”
Host-Bacteria interaction responsible for the
effectiveness of gut immune related mechanisms.
POSTbiotics
POSTbiotics
 Short chain fatty acids (SCFAs) are the products of
colonic bacterial degradation of unabsorbed starch
and non-starch polysaccharide (fibre).
 The main acids: Acetate, Propionate, and Butyrate
and Lactic acid.
 They are important anions in the
colonic lumen, affecting both
Colonocyte Morphology
(Proliferation / Differentiation)
& Function (Tight Colonic Junction
/ Inflammatory Suppression).
SCFA support the critical
Gut mucosal barrier: Keeping Gut integrity
 Butyrate is the preferred energy
substrate for the colonocyte, it
provides fuel (nutrition) for ileal and
colonic epithelial cells, which help
maintain the integrity of the colon.
 LOW Resistant Starch & Fiber Diet
 low SCFA production in colon 
explain the high occurrence of
colonic disorders.
Safe Alternative Therapeutic
Strategy ???????
SCFA help improve
Water & Electrolyte Absorption
and Bowel Movement
• SCFA facilitate the absorption of
water and electrolytes that in turn
helps minimizing the risk of diarrhea
as well as its volume.
• Acetate increases colonic blood
flow and enhances ileal motility.
• SCFA may be involved in the:
Ileo - Colonic Brake”
Stimulates contractions of the
ileum and shortens ileal
emptying.
DYSBiosis
DYSBiosis
 Dysbiosis is the abnormal
microbial colonization of the
intestine , where changes in
Quantity and Quality of flora
become Pathological & Harmful.
 When intestinal flora equilibrium
is disturbed, the optimum expected
health effects are lost 
autoimmune conditions result (IBD,
rheumatoid).
 A common cause of dysbiosis is
antibiotic therapy (Iatrogenic).
Thank your for your
patience
References
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
American Journal of Clinical Nutrition, Vol. 69, No. 5, 1035S – 1045S, May
1999.
Gastroenterology and Nutrition in infancy (GNI).
International Food Information Council (IFIC).
International Food Information Foundation’s Media Guide on Food Safety and
Nutrition.
Nutrition Information Centre University of Stellenbosch (NICUS).
HEALL: Health Education Alliance for Life and Longevity.
Can J Gastroenterol. 2004 Mar;18(3):163-7 Redefining lactose as a conditional
prebiotic.
Daniells, Stephen, Prebiotics Could Reduce Artery Hardening, Boost Heart
Health, NutraIngredients.com, 2 January 2007.
Hamilton-Miller, JMT, Probiotics and Prebiotics in the Elderly, 20 January
2004.
Marco ML et al; Towards understanding molecular modes of probiotic action.
Curr Opin Biotechnol 2006; 17:204–210.
References
11. Prebiotics Could Improve Heart Health, NPICenter.com, 22 December
2006.
12. Saavedra, J.M. and Tschernia, A., Human Studies With Probiotics and
Prebiotics: Clinical Implications, British Journal of Nutrition, Volume 87,
Supplement s2, 1 May 2002, pp. 241-246(6).
13. Rodrigo B., Mathieu M., Chieh J. : Gut Microbiota, Obesity and Diabetes;
(1/2009) Annales Nestle.
14. Roberfroid MB : Prebiotics and probitoics are they functional ? Am J
Clin Nutr; (2000) 71: 1470-1481.
15. Ley RE, Backhed F, Turnbaugh P, et al: Obesity alter gut microbial
ecology. Pro Natl Acad Sci USA 2005;102: 11070-11075.
16. Turnbaug PJ, Backhed F, Fulton L, Gordon JI: Diet –induced obesity is
linked to marked but reversible alteration in mouse distal gut microbiome.
Cell Host Microbe 2008; 3: 213-223.
17. Weickert MO, Pfeiffer AF: Metabolic effects of dietary fiber consumption
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