Probiotics for the Gut
A Guide for Primary Care Physicians
Dr Jarrod Lee
Gastroenterologist & Advanced Endoscopist
Mt Elizabeth Novena Hospital
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Ilya Metchnikov (1845 – 1916)
• “The Father of Probiotics”
• Russian biologist, zoologist
and protozoologist
• Nobel prize in 1908 for
work on phagocytosis
• “Prolongation of Life:
Optimistic Studies” (1907)
– Proposed that ingesting
bacteria could have health
benefits and prolong life
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Human body
• 10 trillion human cells;
23,000 human genes
• 100 trillion bacteria; 3
million genes
“If gut bacteria are
making you ill, can
swapping them out
make you healthy?”
3Economist 2012

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Gut Microbiota

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How Do
We Start?
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Definitions
• Probiotics:
– Live microorganisms that confer a health benefit on the
host when administered in adequate amounts
• Prebiotic:
– Dietary substances that nurture a selected group of micro-
organisms in the gut
– Favouring the growth of beneficial over harmful bacteria
• Synbiotics:
– Products that contain both probiotics and prebiotics
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Lactic Acid Bacteria
• Used for preservation of food by fermentation for
thousands of years
– Fermentation: process by which a microorganism
transforms food into other products
• Found in many yoghurts
– But yoghurts not considered probiotics as not shown to
have an adequate number of viable bacteria specifically
shown to confer health benefits
• Includes Lactobacillus, Lactococcus, Streptococcus
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Lactic Acid
Bacteria
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Probiotic Nomenclature
• Probiotic strains are identified by genus,
species and an alphanumeric designation
• Marketing and trade names are not regulated,
e.g. LGG
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Genus Species Strain
Lactobacillus rhamnosus GG
Lactobacillus casei DN-144 001

Legal Definition
NONE!!!
2011 WGO Minimum Criteria:
• Specified by genus and strain
• Alive
• Delivered in adequate dose through end of shelf life
• Efficacious in controlled human studies
• Safe for intended use
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Prebiotics
• Mostly used as food ingredients
– E.g. biscuits, cereals, chocolates, spreads, dairy products
• Common prebiotics: oligofructose, inulin, lactulose
– Oligofructose found naturally in: wheat, onions, bananas,
honey, garlic, leeks
• Fermentation of oligofructose in colon:
– Increases bifidobacteria numbers
– Increases fecal weight, and shortens GI transit time
• Increased colonic bifidobacteria inhibits pathogens,
reduces ammonia levels, and produces vitamins
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Clinical Indications

How Does It Work?
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Infectious Diarrhea
• Treatment
– 2004 Cochrane review (23 RCTs, 1917 patients) showed
probiotics significantly reduced diarrhea duration by a
mean of 30.5 hours
– 2007 meta-analysis showed similar effect in children
• Prevention
– 2007 meta-analysis (12 RCTs, 4709 patients) showed
modest decrease in risk of travellers diarrhea with
probiotics; RR 0.85
19BMJ 2007; Travel Med Infect Dis 2007

Antibiotic Associated Diarrhea
• Antibiotics cause disturbances in gut flora which lead
to reduced resistance to pathogens such as
Clostridium difficile
• Latest meta-analyses: 2013 Cochrane review
– 23 RCTs, 4213 patients (adults and children)
– Probiotics significantly reduced risk of diarrhea by 64%
(2.0% vs 5.5%)
– Adverse events reduced by 20%
– Similar findings in earlier meta-analyses
• Greatest benefit if started within 72H of antibiotics
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• 19 RCTs, 1650 patients
• Probiotics significantly better than placebo
– RR of symptoms persisting 0.71
– NNT 4
• No difference in type of probiotic used
• More useful for pain, bloating, global improvement
• A meta-analysis of 3 RCTs showed similar effect in
children
21Gut 2010; APT 2011

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Safety
• Safe, few side effects
– Flatulence and mild discomfort
– Mild, self limited
– No long term safety data
• No known interactions with other medications or
supplements
• Rare reports of pathological infection
• Avoid in: short gut syndrome, severely ill or immune
compromised patients
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What Probiotic Strain?
• Lactobacillus and Bifidobacterium species
– Have the most evidence for digestive disorders
– Preferred probiotics for these conditions
– Lactobacillus (especially LGG) has strongest evidence for
acute infectious diarrhea
– Bifidobacterium has strongest evidence for IBS
• Saccharomyces boulardii
– probiotic yeast strain
– proven to be beneficial in diarrhoea conditions
– potential advantage of resistance to most antibiotics
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What Dose?
• In general, higher dosages of > 5 billion CFUs per day
in children, and > 10 billion CFUs per day in adults
were associated with better outcomes
• Studies with Saccharomyces boulardii use a dose of
250 to 500 mg per day
• No evidence that even higher dosages are unsafe,
but may be more expensive and unnecessary
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How Long?
• Survive in the human gut and
detectable in stool
• Do not colonize the gut and not
detectable 1-4 weeks after stopping
• Sustained benefit requires continued
consumption
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Which One to Choose?
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Lacteol Fort
• Lactobacillus acidophilus
• Heat killed and freeze dried
• Works by exclusion:
– Adheres to brush border cells
– Prevents pathogens from attaching, colonizing and
drawing fluid
• “Stimulates growth of acidogenic flora and IgA
synthesis”
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Conclusion
Probiotics are:
• Well proven in studies for specific gut disorders
• Safe to use, but avoid in short gut, severely ill or
immune compromised patients
• Symptomatic effects may be modest; may be best
used as adjuncts rather than replacements for
conventional therapy
• Selection should consider clinical indication, strain
and dosage
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Thank You
Questions to
drjarrodlee@gmail.com
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