Probiotics for Brain Health, Gut Health, and Hormone Balance - Dr. Michael Ruscio, DC

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Probiotics for Brain Health, Gut Health, and Hormone Balance

Findings on PCOS, mastitis, leaky gut syndrome, Alzheimer’s Disease, ulcerative colitis, and more

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➕ Dr. Ruscio’s, DC Notes

Which Conditions the New Probiotic Studies Cover

Polycystic Ovary Syndrome (PCOS)

A study looked at the effects of probiotics on sexual function in women with PCOS.

The parameters:

  • 40 women with PCOS and sexual dysfunction were randomized to Letrozole or Letrozole + synbiotics (lactobacillus species + Fructo-oligosaccharides
    • All patients were given oral folic acid supplementation


The results:

  • After 2 months, the group taking Letrozole and synbiotics, compared to placebo, led to improved: 
    • Pregnancy rate (10% vs 0%) 
    • Sexual function 
    • Body dysmorphia


A study assessed the efficacy of probiotics combined with metformin on improvement of menstrual and metabolic patterns in women with polycystic ovary syndrome. 


The parameters:

  • 60 women with PCOS and irregular menstrual cycles were randomized to probiotics alone, metformin alone, or probiotics and metformin. 

The results:

  • After 23 months, regulation of menstrual cycle occurred in:  
    • 80% in probiotic + metformin group 
    • 55% metformin group 
    • 40% probiotic group



This study analyzed how supplementation of MED-02, a complex supplement containing two probiotic strains, affected body fat and total weight in overweight individuals. 


The parameters:

  • 100 overweight and obese participants were randomized to placebo or probiotics (limolactobacillus strains).  

The results:

  • After 3 months, compared to placebo, the probiotic group experienced reduced:
    • Fat mass (-2.5 lbs vs -0.8 lbs)
    • Total weight (-4.5 lbs vs 2.6 lbs) 
    • Body fat percentage based on DEXA scan (-0.9% vs -0.1%) 


Another study looked at the effects probiotics have on acute mastitis–one of the most common problems in breastfeeding women. 


The parameters:

  • The study included 6 randomized controlled trials featuring 1,096 lactating women. 

The results:

  • Probiotic supplementation (lactobacillus species) led to 51% reduced incidence of mastitis compared to control groups.

Pediatric acute gastroenteritis (PAGE)

This study aimed to compare the efficacy and safety of two probiotics–Saccharomyces boulardii (S.boulardii) and Bacillus clausii (B. clausii)–for the treatment of PAGE. 

The parameters:

  • 312 children between the ages of 6 months–5 years old with acute diarrhea were randomized to S. boulardii or B. clausii.  

The results:

  • After 1 week, S. boulardii led to a shorter duration of diarrhea compared to B. clausii (65 hours vs 78 hours). 
  • Both probiotics led to improved: 
    • Loose stool frequency
    • Diarrhea severity

Ventilator-associated pneumonia (VAP)

A study investigated the preventive effects of pro-, pre- and synbiotics on VAP among critically ill patients. 


The parameters:

  • The study featured 15 randomized controlled trials on critically ill patients.

The results:

  • Compared to control treatments, probiotics, prebiotics and synbiotics led to: 
    • 30% reduced risk of developing VAP
    • Shorter duration of ventilation (-1.6 days)
    • Fewer days in the ICU (-1.7 days)


Stress and viral illnesses 

This study intended to establish whether daily probiotic use can reduce stress and the number of days healthy nurses reported symptoms of a viral illness. 


The parameters:

  • 484 healthy nurses during the Covid-19 pandemic were randomized to placebo or probiotics (lactobacillus rhamnosus). 

The results:

  • After 3 months, there was no difference between groups for:
    • Perceived stress
    • Anxiety
    • Wellbeing
    • Number of days sick

Ulcerative colitis (UC)

A study investigated the use of Escherichia coli Nissle 1917 (EcN) as an add-on therapy for UC.


The parameters:

  • 133 UC patients on 5-ASA (a type of UC medication) medication were randomized to placebo or EcN. 

The results:

  • After 2 months, compared to placebo, EcN group experienced:
    • Higher rates of clinical remission (40% vs 22%) 
    • Higher rates of endoscopic remission (46% vs 27%) 
    • NO difference in improvement of IBD scores 
    • Fewer patients worsening IBD scores (1.7% vs 13.3%)


Brain health

This study looked at the cognitive benefits of probiotics in physically active older adults.


The parameters:

  • 127 physically active healthy adults were treated with probiotics (Lactobacillus rhamnosus GG) 

The results:

  • Probiotics did not lead to improved cognition in healthy adults who were physically active


While this review and meta-analysis looked at probiotic support in patients with Alzheimer’s.

The parameters:

  • 5 randomized controlled trials were included, with a total sample size of 386 cases 

The results: 

  • Probiotics led to improvements in:
    • Cognitive function 
    • Acute memory 
    • Ability to perform activities of daily living


The Effectiveness of Probiotics

This study looked at how effective probiotics are at “restoring eubiosis in patients with drug-induced dysbiosis or other pathological conditions, which could be caused by stress, wrong eating.”

The parameters:

  • In vitro study comparing 4 types of store-bought probiotics. The disintegration of probiotic capsules in hydrochloric acid (conditions simulating the gastrointestinal tract) was timed and investigated.

The results:

  • This study found that the outer capsule was important, as well as “The best antimicrobial activity against most common human gastrointestinal pathogens such as Eschericha coli, Shigella, Salmonella spp., Clostridium difficile are shown by probiotic products with the greatest diversity of bacterial strains. This preclinical study supports the use of using a multi-strain probiotic formula vs specific individual strains.

Atopic Dermatitis 

This study looked at the effects of probiotics in children with atopic dermatitis. 

The parameters:

  • 100 pediatric patients with eczema were randomized to placebo or probiotics (lactobacillus rhamnosus GG) 

The results:

  • After 3 months, compared to placebo, probiotics led to:
    • Higher response rate for reduced eczema severity (60% probiotic vs 20% placebo) 
    • NO difference in gut microbiome based on stool test
    • Improvements in eczema were maintained 1 month after stopping probiotics 

The last study looked at the effect of a multistrain probiotic on leaky gut in IBS-D patients

The parameters:

  • This was an open-label study of 27 patients with IBS-D and leaky gut who were treated with multi-strain probiotics (lacto/bifido blend) 
  • “Leaky gut” was determined based on radionuclide tracers and serum zonulin 

The results:

After 1 month, probiotics led to:

  • 96% experienced satisfactory symptom relief 
  • Improved leaky gut in 82%
  • Normalization of leaky gut in 37%
  • Improved quality of life 
  • Improved abdominal pain and diarrhea
➕ Resources & Links

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