Probiotics have shown promise in alleviating symptoms of irritable bowel syndrome (IBS) based on several clinical studies. However, the results have been mixed, possibly due to differences in probiotic strains used and limitations such as small sample sizes and short study durations. Overall, multiple studies found improvements in IBS symptoms like abdominal pain and changes in bowel movements when taking probiotics, but larger and longer trials are still needed to confirm their effectiveness for treating IBS. Future research should aim to standardize study methods and closely monitor subjects to better determine the potential benefits of probiotics.

1. The Efficacy of Probiotics on
Alleviating IBS Symptoms
Sloane Kaye, Graduate Student of Nutritional Science
California State University

2. Irritable Bowel Syndrome (IBS)
 Defined as a group of intestinal symptoms which commonly occur together, causing
discomfort in an individual’s bowel movements.
 common gastrointestinal disorder
 Affecting approximately 10-15% of the population
 No definitive test to diagnosis IBS
 Diagnostic testing include:
 blood tests (check for anemia, abnormalities, and inflammation)
 stool tests (most commonly used to check for bacterial infections)
 psychological testing with the use of questionnaires to detect anxiety, stress or other
psychological problems

3. IBS – Continued…
 Sub typed into three categories known as the Rome Criteria based upon the main symptom
of the bowel habit
 IBS-C (IBS with constipation)
 IBS-D (IBS with diarrhea)
 IBS-M (IBS with mixed symptoms)
 IBS symptoms must last for a least three months and for at least three days per month
 IBS is a long-term condition, symptoms include:
 abdominal pain, bloating, gas, cramping, constipation, and diarrhea
 Risk factors:
 gender (IBS is almost twice as common in women than men), environmental factors, genetic
factors, food intolerance, altered nervous system, altered hormonal regulation, oversensitive
intestines, bacterial overgrowth, and bacterial activity in the gut, stress, anxiety

4. IBS Continued
 Treatment of IBS:
 medications, fiber supplements, laxatives, anti-diarrheal, antidepressants, and other pain
relievers
 Focus of treatment is relieving the associated symptoms
 Stress relief, changes in diet and lifestyle
 Elimination of high gas foods gluten
 Restrictive Diet
 Sensitive to certain carbohydrates (FODMAS)
 Lactose, fructans, or fructose
 Causes of IBS are unknown
 Proposed causation: bacterial imbalance of the gut
 Alternative therapy to relieve IBS symptoms through use of probiotics
 Probiotics are termed as “good bacteria”

5. Purpose/ Aim
 Research about the role of probiotics on health increased over the years
 Some experts advise probiotics to be a conducive for IBS others aren’t as convinced
AIM: Investigate the use of probiotics as an effective treatment measure in alleviating symptoms
for IBS

6. Methods
 Literature Review for evidence analysis
 Databases: PubMed, Wiley Online Library, GoogleScholar, and Web of Science
 Keywords: probiotics, gut dysbiosis, irritable bowel syndrome, IBS, Colonic
fermentation, microbiota, digestive system diseases, and gut
 Inclusion Criteria: full-text peer-review articles, past ten years, cohort, cross-
sectional studies, random clinical trials, humans, published in English
 Exclusion Criteria: Published prior to 2008, if topic at large was unrelated, review
articles, meta-analysis, and animal trials

7. Summary of Evidence
(Min et al., 2012)
 Randomized, double-blind control Trial
 130 subjects
 Investigate effects of composite yogurt enriched with acacia dietary fiber has a therapeutic effect on
patients diagnosed with irritable bowel syndrome
 Subjects reported improvements in bowel habit satisfaction, and symptoms related to IBS
 Alleviated symptoms were founded to be statistically significant
 Consistent with previous studies
 Limitations: short length of study, dietary analysis

8. Summary of Evidence
(Mezzasalma et al., 2016)
 Randomized, double-blind placebo-controlled, clinical trial
 Administered two formulations containing different probiotic strains
 The aim of the study was to explore the efficacy of two probiotic formulations in
ameliorating symptoms of IBS
 Understood level of bifidobacteria and lactobacilli species is lower in IBS patients
 Analyzed the initial variations in the intestinal microbiota
 Significant differences in the reported severity of symptoms between the two probiotic
groups and the placebo
 Subjects reported a decrease of at least 30% when compared to the initial baseline
conditions.
 limitation of study done in a tertiary health care center

9. Summary of Evidence
 Šmid et al., 2016
 Randomized double-blind control trial, 76 IBS- C patients
 Aim of the study was focused on the effect of fermented milk with probiotic
cultures Lactobacillus acidophilus and Bifidobacterium, and dietary fibers on
improvement of symptoms associated with IBS- C
 18% improvement in the IBS- QoL score
 significant improvements in bloating severity, and satisfaction with bowel
movements
 Limitation: Failure to meet target recruitment, reduced study power

10. Summary of Evidence
Guyonnet, et al., 2007
 Large‐scale, multicentre, randomized, controlled clinical trial
 6-week trial
 Aimed at assessing the effects of fermented milk on 274 primary care adults with constipation
predominant IBS
 Fermented milk contained the strain B. animalis DN-173
 resistant to acid and oxidative stress, and shown to be well-suited for formulated fermented milk
products
 clinically relevant, such as immune modulation, enhancement of gut-barrier function, and shorten
colonic transit
 Improvements in both stool frequency and consistency, shown rapid improvement in week 1 and
was sustained throughout the entire study
 Consistent with previous findings, the study observed that the probiotics tested may accelerate
the intestinal, especially colonic and sigmoid speed of transit

11. Summary of Evidence
Kajander et al., 2005
 Randomized, double-blind placebo-controlled trial
 Length: 6-months; 103 patients (Rome I or II criteria)
 Examine whether probiotic therapy using LGG, L. rhamnosus LC705, B. breve Bb99
and P. freudenreichii ssp. shermanii JS is effective in alleviating IBS symptoms
 Results indicate that the probiotic mixture is helpful in treating IBS symptoms
 Lactobacilli and bifidobacteria are considered to be safe for healthy and
immunosuppressed individuals
 No apparent adverse effects were observed

12. Summary of Evidence
Roberts et al., 2013
 Double-blind randomized control trial
 179 subjects, across 13 general practices within Central England
 Aim was to assess the effects of the commercially available fermented product on
alleviating the individual symptom for individuals with IBS.
 Analyzed stool frequency, consistency, bowel movements, IBS specific symptoms, and
quality of life.
 Significant improvements were reported for most outcomes in all trial participants
 Improvements was maintained throughout the 12-week period of observations
 Known “placebo” effect observed in control group

13. Discussion
 Manifestations of IBS is unknown
 Previous literature have connected IBS with gut-brain axis interactions, microbiome disruption, genetic
and environmental factors
 Alterations in the microbial flora
 Despite advances in pharmacological approaches, use of probiotics has been confirmed across studies
 Probiotics are multifunctional, ability to stabilize immune dysregulation
 Probiotics can modify the intestinal microbiota, altering microbiotic makeup, and reduce flatulence
 Although, probiotics exert beneficial effects, they can also produce negative ones as well

14. Discussion Cont.…
 Analysis of the studies:
 Overall improvements were shown in alleviating the common symptoms of IBS
 Symptoms begins to attrition toward weeks 8 to 10 or taken off probiotic treatment
 Observed reduced effectiveness with long-term use
 Major limitation use of different strains of probiotics, diversity of subjects for symptoms
 Collectively, studies were small sample size, short duration, and controlled clinical trials
 Use of probiotics in conjunction with our own microbiome is complex
 Takes time for a synergetic effect to emerge

15. Discussion Cont.…
 Controlled environment is necessary
 Strict dietary measures
 Extraneous variables need to be closely scrutinized and accounted for
 Misclassification of data, skew outcome
 Further clinical trials are still needed to confirm the effectiveness of probiotics IBS
patients

16. Conclusion
 Studies conducted on probiotics in patients with IBS, have shown mixed results
 Complex nature of the disease
 No definitive test to diagnose those with the disease
 IBS is likely due to a multitude of causes
 Likelihood of finding one particular probiotic strain or mix to cure all is unlikely
 Overall results for use of probiotics are promising
 More trials are necessary before physicians can be confident in prescribing
probiotics on a routine basis

17. Suggestions for Future Research
 Further exploration is needed to determine the efficacy of probiotics on IBS treatment
of symptoms
 Include longer studies, larger group of subjects
 dietary intake of the subjects should be closely monitored
 Standardize methods
 Questionnaire
 Protocol
 Newly, innovative technologies emerge, research in this particular field is expected to
grow at an exponential pace
 Use of probiotics has the potential to contribute to treat IBS symptoms, researchers
must continue pursuing rigorous studies