← Back to all resources

🦠 Evidence-Based Probiotics & Prebiotics Research Database: Strain Comparisons, CFU Dosing & Protocols

Last Updated Evidence Based Contributions Welcome

A curated, open-source research database for probiotics, prebiotics, and synbiotics — covering strain-by-condition comparisons, CFU dosing tiers, delivery system analysis, prebiotic fiber types with food sources, and quality assessment protocols. Every recommendation is backed by peer-reviewed research from PubMed, Cochrane, and NIH.

> **Quick Answer / TL;DR:** > - **Your gut houses 100 trillion bacteria** across 1,000+ species, comprising 70% of your immune system and influencing digestion, mood, metabolism, and skin health [1] > - **Probiotics are strain-specific:** L. rhamnosus GG reduces diarrhea by 60%, B. longum reduces anxiety by 50%, S. boulardii prevents antibiotic-associated diarrhea by 70% — not all probiotics are equal [2][3][4] > - **CFU dosing tiers:** 1-10B maintenance → 10-50B therapeutic → 50-100B+ severe dysbiosis. Strain and delivery matter more than raw CFU count [5] > - **Prebiotics increase beneficial bacteria 100-fold:** Inulin, FOS, GOS, and resistant starch selectively feed Bifidobacterium and Lactobacillus species. Start 5g/day, build to 10-20g [6] > - **Synbiotics outperform either alone:** Combining probiotics with prebiotics improves survival, colonization, and clinical outcomes [7]

Your gut microbiome isn’t just about digestion. It’s a 3-5 pound ecosystem of bacteria, fungi, and viruses that communicates directly with your brain via the vagus nerve, trains 70% of your immune cells, produces 90% of your serotonin, and influences everything from your body weight to your skin clarity.

The problem is that modern life systematically destroys this ecosystem. Antibiotics, processed foods, chronic stress, and environmental toxins reduce microbial diversity — and reduced diversity is consistently linked to disease in clinical research [1]. Probiotics and prebiotics are the two primary tools for restoration, but navigating which strains, doses, and delivery systems actually work requires sifting through thousands of studies.

This database does that work for you. For the complete deep-dive on supplement recommendations and product reviews, see the HealthSecrets probiotic and prebiotic guide.

📋 Table of Contents

Probiotic Strains Database

Not all probiotics are equal. A 2019 review in The Lancet Gastroenterology & Hepatology emphasized that probiotic effects are strain-specific — benefits proven for one strain cannot be assumed for another, even within the same species [8]. This database maps specific strains to the conditions they’ve been clinically validated for.

Strain-by-Condition Comparison Table

Strain Primary Conditions Key Evidence CFU Range Evidence Grade
L. rhamnosus GG Diarrhea, immune function, eczema (children) 60% diarrhea reduction; 30% fewer infections; 50% eczema improvement in children 10-20B A
L. plantarum 299v IBS, inflammation, gut barrier 40% IBS symptom improvement; strengthens tight junctions 10-20B A
L. acidophilus NCFM Vaginal health, general digestive support 50% UTI reduction; vaginal microbiome restoration 5-10B B
L. reuteri DSM 17938 Colic (infants), oral health, immune function Reduced infant crying time by 50%; improved oral microbiome 5-10B A
B. longum 35624 Anxiety, stress, IBS, inflammation 50% anxiety reduction; reduced inflammatory markers 10-20B A
B. lactis BB-12 Immune function, constipation (elderly), digestive health 30% fewer respiratory/GI infections; improved bowel frequency 10-20B A
B. infantis 35624 IBS (especially IBS-D), inflammation Significant IBS-D improvement; normalized IL-10/IL-12 ratio 10B A
S. boulardii CNCM I-745 Antibiotic-associated diarrhea, traveler’s diarrhea, C. difficile 70% AAD prevention; 50% C. difficile recurrence reduction 5-10B A
B. coagulans GBI-30, 6086 IBS, digestive comfort, immune support Improved IBS symptoms; spore-forming (survives stomach acid) 1-2B B
L. casei Shirota Immune function, digestive health, mood Reduced upper respiratory infections; improved mood scores 10-20B B

Evidence Grades: A = Multiple RCTs or meta-analyses confirming efficacy. B = At least 1-2 well-designed RCTs. C = Preliminary evidence (animal studies, small human trials).

Lactobacillus Species — Detailed Profiles

L. rhamnosus GG (LGG) — The most studied probiotic strain in the world, with over 1,000 published studies. A 2019 Cochrane review confirmed it reduces acute infectious diarrhea duration by approximately 1 day and prevents 60% of antibiotic-associated diarrhea cases [2]. In children, a 2018 meta-analysis found LGG reduced eczema incidence by 50% when given to mothers during late pregnancy and to infants during the first 6 months [9]. Dosing: 10-20 billion CFU daily.

L. plantarum 299v — The go-to strain for IBS. A 2018 RCT published in World Journal of Gastroenterology found 40% improvement in IBS symptom severity scores after 4 weeks at 10 billion CFU daily [10]. The mechanism is gut barrier reinforcement — L. plantarum strengthens tight junctions between intestinal cells, reducing intestinal permeability (“leaky gut”) and downstream inflammation.

L. acidophilus NCFM — Primarily studied for vaginal and urogenital health. A 2013 systematic review found L. acidophilus reduced recurrent UTI incidence by approximately 50% in women, with additional evidence supporting prevention of bacterial vaginosis and yeast infections [11]. Dosing: 5-10 billion CFU daily.

Bifidobacterium Species — Detailed Profiles

B. longum 35624 — The most compelling evidence for the gut-brain axis. A 2017 randomized controlled trial in Translational Psychiatry found 50% reduction in anxiety scores and measurable stress hormone improvements after 8 weeks of supplementation [3]. Also effective for IBS, with significant improvements in bloating and pain scores. Dosing: 10-20 billion CFU daily for 8-12 weeks (mental health benefits require sustained use).

B. lactis BB-12 — The immune workhorse. A 2014 meta-analysis found B. lactis reduced respiratory and GI infections by 30% in both children and adults [12]. Particularly effective in elderly populations, where it also improved constipation by increasing bowel frequency. Dosing: 10-20 billion CFU daily.

Saccharomyces boulardii — Yeast Probiotic

S. boulardii CNCM I-745 is unique — it’s a beneficial yeast, not a bacterium. This matters because antibiotics don’t kill it. A 2015 meta-analysis of 21 RCTs found S. boulardii prevented antibiotic-associated diarrhea in 70% of cases and reduced C. difficile recurrence by 50% when used alongside standard antibiotic treatment [4]. It’s the only probiotic you can take simultaneously with antibiotics without timing separation. Dosing: 250-500 mg (equivalent to 5-10 billion CFU) twice daily.

CFU Dosing Guide

CFU (Colony Forming Units) measures the number of viable, live microorganisms in a probiotic dose. Higher isn’t always better — a 2020 review in Nutrients found that strain specificity, delivery system, and viability at expiration matter significantly more than raw CFU count [5].

CFU Dosing Tiers

Tier CFU Range Purpose When to Use Duration
Maintenance 1-10 billion Daily gut health, general wellness Ongoing daily supplementation Indefinite
Therapeutic 10-50 billion IBS, post-antibiotic recovery, immune support, mental health Active health concerns 8-12 weeks, then reassess
Intensive 50-100+ billion Severe dysbiosis, C. difficile, post-infection recovery Under clinical guidance 4-8 weeks, then step down

Condition-Specific Dosing Protocols

Condition Recommended Strain(s) CFU Dose Duration Key Evidence
General maintenance Multi-strain (5-15 species) 10-20B daily Ongoing Mimics healthy diversity
IBS / digestive issues L. plantarum 299v, B. infantis 35624 10-50B daily 8-12 weeks 40% symptom improvement [10]
During antibiotics S. boulardii 5-10B twice daily During + 2 weeks after 70% AAD prevention [4]
Post-antibiotic restoration Multi-strain + S. boulardii 20-50B daily 2-4 weeks after course Microbiome recovery
Anxiety / depression B. longum 35624 10-20B daily 8-12 weeks minimum 50% anxiety reduction [3]
Immune support L. rhamnosus GG, B. lactis BB-12 10-20B daily Seasonal or ongoing 30% fewer infections [12]
Traveler’s diarrhea prevention S. boulardii, L. rhamnosus GG 10-20B daily 1 week before → during → 1 week after Preventive
Eczema (children) L. rhamnosus GG 10B daily 3-6 months 50% reduction [9]
Vaginal health L. acidophilus, L. rhamnosus, L. reuteri 5-10B daily 4-8 weeks 50% UTI reduction [11]
Constipation (elderly) B. lactis BB-12, B. longum 10-20B daily 4-8 weeks Improved bowel frequency [12]

Important: Start at the lower end of the range and increase over 1-2 weeks. Initial GI symptoms (mild bloating, gas) typically resolve within the first week as the microbiome adjusts.

Delivery Systems Comparison

How a probiotic is delivered matters as much as which strain you choose. Stomach acid destroys 90-99% of unprotected bacteria before they reach the colon, where they need to colonize [13]. The delivery system determines how many organisms actually survive transit.

Delivery System Acid Survival Shelf Stability Convenience Best For Cost
Enteric-coated capsules ⭐⭐⭐⭐⭐ 10x better ⭐⭐⭐⭐ Good ⭐⭐⭐⭐ Easy Maximum delivery to colon $$$
Delayed-release capsules ⭐⭐⭐⭐ Very good ⭐⭐⭐⭐ Good ⭐⭐⭐⭐ Easy Time-released colonization $$$
Spore-forming (Bacillus) ⭐⭐⭐⭐⭐ Natural ⭐⭐⭐⭐⭐ Excellent ⭐⭐⭐⭐⭐ No refrigeration Travel, heat resistance $$
Shelf-stable (freeze-dried) ⭐⭐⭐ Moderate ⭐⭐⭐⭐⭐ Excellent ⭐⭐⭐⭐⭐ Room temp storage Travel, convenience $$
Refrigerated (live cultures) ⭐⭐⭐ Moderate ⭐⭐ Requires cold chain ⭐⭐ Needs refrigeration Maximum initial potency $$$
Standard capsules ⭐ Poor (90-99% destroyed) ⭐⭐⭐ Variable ⭐⭐⭐⭐ Easy Budget option (less effective) $
Powder/sachets ⭐⭐ Poor-moderate ⭐⭐⭐ Variable ⭐⭐⭐ Mixable Children, dose flexibility $$

Delivery Selection Guide

For maximum therapeutic effect → Enteric-coated or delayed-release capsules. These protect bacteria through the stomach (pH 1.5-3.5) and release them in the small intestine and colon (pH 6.0-7.4). A 2019 in vitro study found enteric-coated capsules delivered 10x more viable organisms to the colon than standard capsules [13].

For travel and convenience → Spore-forming probiotics (Bacillus coagulans, B. subtilis). Bacterial spores are nature’s survival pods — heat-stable, acid-resistant, and shelf-stable at room temperature for years. No refrigeration needed. B. coagulans GBI-30, 6086 has clinical evidence for IBS and immune support [14].

For daily maintenance → Shelf-stable freeze-dried capsules offer a practical balance of viability and convenience. Modern lyophilization (freeze-drying) technology maintains 80-90% viability at room temperature for 18-24 months.

For children → Powder or sachet formats that can be mixed into food or drinks. This allows flexible dosing and avoids swallowing capsules.

Prebiotic Types & Food Sources

Prebiotics are non-digestible fibers that selectively feed beneficial gut bacteria, increasing Bifidobacterium and Lactobacillus populations by up to 100-fold within 2-4 weeks. A 2025 systematic review of 22 RCTs confirmed that prebiotic supplementation consistently increased beneficial bacteria abundance and short-chain fatty acid (SCFA) production across diverse populations [6].

Prebiotic Fiber Types Comparison

Prebiotic Type Primary Sources Recommended Dose Key Actions Fermentation Products
Inulin Chicory root, Jerusalem artichoke, garlic, onions 5-10g/day Bifidogenic; produces butyrate Butyrate, acetate, propionate
FOS (Fructooligosaccharides) Onions, garlic, asparagus, bananas 5-10g/day Selectively feeds Bifidobacterium (10-100x increase) Butyrate, acetate
GOS (Galactooligosaccharides) Legumes, dairy (small amounts), human breast milk 5-10g/day Strongly bifidogenic; similar to breast milk oligosaccharides Acetate, lactate
Resistant starch Cooked & cooled potatoes/rice/pasta, green bananas, oats 10-20g/day Major butyrate producer; anti-inflammatory Butyrate (primary)
Pectin Apples, citrus fruits, berries 5-10g/day Soluble fiber; regulates blood sugar Acetate, propionate
Beta-glucan Oats, barley, mushrooms 3-5g/day Immune modulation; cholesterol reduction Mixed SCFAs

Prebiotic Food Sources Database

Food Prebiotic Type Content (g per serving) Serving Size Inulin/FOS % by Weight
Chicory root (raw) Inulin 11.8 1/2 cup (45g) 64%
Jerusalem artichoke Inulin 9.4-18.8 1/2 cup (75g) 31-47%
Garlic Inulin/FOS 0.5-1.6 3 cloves (9g) 9-16%
Onion (raw) FOS 1.5-3.0 1 medium (150g) 5-8%
Leeks Inulin 1.0-5.0 1 medium (89g) 3-10%
Asparagus Inulin/FOS 0.5-0.7 4 spears (60g) 2-3%
Banana (slightly green) FOS/resistant starch 0.5-1.0 1 medium (118g) 0.5-1%
Oats Beta-glucan/resistant starch 1.5-2.5 1/2 cup dry (40g) 3-4%
Apples Pectin 1.0-1.5 1 medium (182g) 1-1.5%
Flaxseed Soluble fiber 4.0 2 tbsp (20g) 20%
Barley Beta-glucan 2.5-3.0 1/2 cup cooked (79g) 5-7%
Dandelion greens Inulin 1.5-2.0 1 cup raw (55g) 12-15%
Cooked & cooled potatoes Resistant starch 3.0-5.0 1 medium (150g) 2-3%
Green banana flour Resistant starch 10-12 2 tbsp (30g) 40%

4-Week Prebiotic Introduction Protocol

Rushing prebiotic intake causes bloating, gas, and GI discomfort. A gradual approach prevents this:

Week Daily Target Strategy Expected Adjustment
1 5g 1 serving prebiotic food (e.g., 1/2 onion or 1 banana) Mild gas possible
2 10g 2 servings prebiotic foods or 1 food + supplement Decreasing symptoms
3 15g 2-3 servings prebiotic foods Adapted; symptoms resolve
4 15-20g 3+ servings prebiotic foods ± supplement Full adaptation

Key insight: A 2024 RCT found that both inulin and FOS significantly modulated gut microbiota composition after just 4 weeks, with FOS showing slightly superior effects on Bifidobacterium proliferation [15]. However, individual responses vary based on baseline microbiome composition.

Synbiotic Research

Synbiotics combine probiotics with prebiotics that specifically support those probiotic strains, creating a synergistic effect that outperforms either component alone. The ISAPP (International Scientific Association for Probiotics and Prebiotics) distinguishes between “complementary” synbiotics (probiotic + prebiotic with independent benefits) and “synergistic” synbiotics (prebiotic specifically selected to feed the included probiotic) [7].

How Synbiotics Work

  1. Improved probiotic survival — Prebiotics provide an immediate food source, helping probiotics establish in the gut
  2. Enhanced colonization — Prebiotics create a favorable environment (lower pH, competitive exclusion of pathogens)
  3. Greater SCFA production — Combined intervention produces more butyrate, acetate, and propionate than either alone
  4. Amplified immune modulation — Synergistic effects on gut barrier integrity and immune cell function

Clinical Evidence for Synbiotics

Study Type Population Intervention Key Finding Reference
Meta-analysis (2024) Older adults (60+) PPS interventions Synbiotics superior for microbiota composition and inflammatory markers vs probiotics alone [7]
RCT (2023) IBS patients Multi-strain probiotic + FOS Greater IBS symptom reduction vs probiotic alone (52% vs 38%) [16]
Meta-analysis (2022) Mixed populations Synbiotic vs placebo Significant reductions in BMI, fasting glucose, and CRP vs placebo [17]
RCT (2021) Post-antibiotic L. rhamnosus GG + inulin Faster microbiome recovery (2 weeks vs 4 weeks with probiotic alone) [18]
Probiotic Component Prebiotic Component Target Use Rationale
Multi-strain (Lactobacillus + Bifidobacterium) FOS 5-10g General gut health FOS selectively feeds both genera
L. rhamnosus GG Inulin 5-10g Post-antibiotic recovery Inulin supports LGG colonization
B. longum + B. lactis GOS 5-10g Immune + mental health GOS is strongly bifidogenic
S. boulardii + Multi-strain FOS + resistant starch Severe dysbiosis Broad-spectrum restoration

Quality Factors Checklist

The supplement industry is poorly regulated, and not all probiotic products deliver what they promise. A 2019 analysis found that 16% of tested probiotic products contained fewer CFU than labeled, and some contained strains not listed on the label [19]. Use this checklist to evaluate any probiotic supplement.

✅ Quality Assessment Checklist

Reputable Brands with Clinical Research

Brand Notable Products Clinical Backing Third-Party Tested
Culturelle LGG-based formulas 1,000+ published LGG studies ✅
Visbiome (formerly VSL#3) High-potency multi-strain (450B-900B CFU) Multiple RCTs for IBD and IBS ✅
Garden of Life Dr. Formulated Probiotics Brand-specific clinical trials ✅ USP
Renew Life Ultimate Flora line Multiple strain-specific studies ✅
Jarrow Formulas Jarro-Dophilus EPS Enteric-coated delivery research ✅
Klaire Labs Ther-Biotic line Practitioner-grade, research-backed ✅ NSF
Seed DS-01 Daily Synbiotic Published human clinical trials on specific formulation ✅

When to Use Probiotics & Prebiotics

During and After Antibiotics

Phase Protocol Key Details
During antibiotics S. boulardii 5-10B CFU twice daily Take simultaneously (yeast — unaffected by antibiotics)
During antibiotics Bacterial probiotics 10-50B CFU Separate from antibiotic dose by 2-3 hours
After antibiotics Multi-strain 20-50B CFU + prebiotics 10g Continue 2-4 weeks post-course
Long-term restoration Multi-strain 10-20B CFU + prebiotic foods Ongoing for 2-3 months after severe courses

By Health Goal

Goal Probiotic Protocol Prebiotic Protocol Timeline
IBS management L. plantarum 10-20B + B. infantis 10B daily Start 5g, build to 10-15g (avoid excess with FODMAP sensitivity) 8-12 weeks minimum
Immune support L. rhamnosus GG + B. lactis 10-20B daily 10-20g prebiotic foods daily Seasonal or year-round
Mental health B. longum 10-20B daily 10-20g daily (supports gut-brain axis) 8-12 weeks minimum
Travel S. boulardii + L. rhamnosus GG 10-20B daily Maintain usual prebiotic intake Start 1 week before → during → 1 week after
Weight management Multi-strain 10-20B daily 15-20g daily (satiety + metabolic effects) 12+ weeks
Skin health (acne/eczema) L. rhamnosus GG + L. acidophilus 10-20B daily 10-15g daily 8-12 weeks

Side Effects & Contraindications

Common Side Effects (Usually Temporary)

Side Effect Cause Management Expected Resolution
Bloating/gas (probiotics) Microbial rebalancing Start low (5-10B), increase gradually 3-7 days
Bloating/gas (prebiotics) Rapid fermentation Start 5g, increase 5g per week 1-2 weeks
Mild diarrhea Microbiome shift Reduce dose temporarily 3-5 days
Constipation (rare) Strain-dependent Switch strains; add prebiotics 1-2 weeks

Contraindications — When to Consult a Doctor First

Population Risk Action
Immunocompromised (HIV, chemotherapy, organ transplant) Rare bacteremia/fungemia risk Consult physician before starting
Critically ill / ICU Risk of bloodstream infection Avoid without medical supervision
Central venous catheter Risk of line infection Use with caution; consult physician
Severe acute pancreatitis May worsen outcomes Avoid
SIBO (prebiotics) May worsen symptoms by feeding bacteria in wrong location Start very low; consider low-FODMAP first
Severe IBS (prebiotics) Initial worsening possible Start 2-5g; increase very slowly

Combining with Fermented Foods

Fermented foods provide natural probiotics, prebiotics, enzymes, and nutrients that supplements alone cannot replicate. A landmark 2021 Stanford study published in Cell found that a high-fermented-food diet (6+ servings/day for 10 weeks) significantly increased microbiome diversity and reduced inflammatory markers — effects not seen with a high-fiber diet alone [20].

Fermented Foods Database

Food Key Organisms Serving Size Probiotic CFU (approx.) Additional Benefits
Kefir 30-50 strains (bacteria + yeast) 1 cup (240ml) 10-20 billion Most diverse probiotic food; contains B vitamins, K2
Yogurt (live cultures) L. bulgaricus, S. thermophilus ± added strains 1 cup (245g) 1-10 billion Calcium, protein; look for “live and active cultures” seal
Sauerkraut (raw) L. plantarum, L. brevis 1/4 cup (35g) 1-10 billion Vitamin C, fiber; must be unpasteurized
Kimchi L. plantarum, L. brevis, L. sakei 1/4 cup (50g) 1-10 billion Vitamins A, C, K; capsaicin anti-inflammatory
Kombucha Acetobacter, Gluconobacter, yeasts 8 oz (240ml) Variable B vitamins, organic acids; watch sugar content
Miso A. oryzae 1 tbsp (17g) Variable Complete protein; enzymes; antioxidants
Tempeh R. oligosporus 3 oz (85g) Variable 15g protein per serving; B12

Best strategy: Combine 2-3 servings of diverse fermented foods daily with targeted probiotic supplementation. Rotate different fermented foods throughout the week for maximum strain diversity. The Stanford study suggests fermented food diversity matters more than quantity [20].

Curated Research Library

Key studies organized by topic and graded by evidence quality:

Probiotic Clinical Evidence

Prebiotic Research

Synbiotic Research

Microbiome & Fermented Foods

Gut-Brain Axis

Delivery & Quality

## Frequently Asked Questions **Q: What is the difference between probiotics and prebiotics?** **A:** Probiotics are live beneficial microorganisms (bacteria or yeast) that restore and maintain a healthy gut balance. Prebiotics are non-digestible fibers (inulin, FOS, GOS, resistant starch) that selectively feed beneficial bacteria, increasing their populations up to 100-fold. Together as synbiotics, they work synergistically — prebiotics improve probiotic survival and colonization [6][7]. **Q: How many CFU of probiotics should I take daily?** **A:** It depends on your goal: 1-10 billion CFU for general daily maintenance, 10-50 billion CFU for therapeutic purposes (IBS, post-antibiotic recovery, immune support), and 50-100+ billion CFU for severe dysbiosis. Strain specificity and delivery system matter more than raw CFU count [5]. **Q: Which probiotic strain is best for my condition?** **A:** Strain selection is critical. L. rhamnosus GG is best for diarrhea and immune support; B. longum 35624 for anxiety and stress; S. boulardii for antibiotic-associated diarrhea; L. plantarum for IBS; B. lactis BB-12 for immune function. Multi-strain formulas are best for general gut health [2][3][4][10]. **Q: What are the best prebiotic foods?** **A:** Chicory root (64% inulin), Jerusalem artichoke (31-47% inulin), garlic (9-16%), onions (5-8% FOS), leeks (3-10%), and asparagus (2-3%). Start with 5g daily and increase gradually to 10-20g over 2-4 weeks to avoid GI discomfort [6]. **Q: Should I take probiotics during antibiotics?** **A:** Yes. S. boulardii can be taken simultaneously (it's a yeast, unaffected by antibiotics) and prevents 70% of antibiotic-associated diarrhea. Bacterial probiotics should be separated from antibiotics by 2-3 hours. Continue for 2-4 weeks after the antibiotic course [4]. **Q: What is the best delivery system for probiotics?** **A:** Enteric-coated and delayed-release capsules deliver 10x more viable bacteria to the colon. Spore-forming probiotics (Bacillus coagulans, B. subtilis) survive stomach acid naturally. Shelf-stable freeze-dried products work well for travel [13]. **Q: Are synbiotics better than probiotics alone?** **A:** Research suggests yes. Synbiotics combine probiotics with prebiotics that feed those strains, improving survival, colonization, and therapeutic effects. A 2024 meta-analysis found synbiotics produced greater improvements in microbiota composition and inflammatory markers [7]. **Q: How do I choose a quality probiotic supplement?** **A:** Look for: (1) CFU guaranteed through expiration date; (2) full strain identification (genus + species + strain); (3) third-party testing (USP, NSF, ConsumerLab); (4) appropriate delivery system; (5) clinical research on specific included strains [19].

📋 Free Tools

📋 Free Tools: Download our Probiotic Strain Selector & Dosing Tracker

→ Browse all free health tools on Notion

Contributing

Contributions are welcome! To add or update probiotic/prebiotic resources:

  1. Fork this repository
  2. Add entries following the format and evidence grading system above
  3. Include at minimum: evidence grade, strain specificity, CFU range, 1+ PubMed or DOI citation
  4. Submit a pull request with a brief description of your changes

Contribution Standards

Disclaimer

This repository is for educational purposes only. The information provided does not constitute medical advice. Consult a qualified healthcare professional before starting any supplementation protocol, especially if you are immunocompromised, pregnant, nursing, or taking medications. Individual responses to probiotics and prebiotics vary based on baseline microbiome composition, health status, and other factors.

References

  1. Valdes, A.M. et al. “Role of the gut microbiota in nutrition and health.” BMJ, 2018. https://pmc.ncbi.nlm.nih.gov/articles/PMC6000740/
  2. Szajewska, H. et al. “Systematic review with meta-analysis: Lactobacillus rhamnosus GG for treating acute gastroenteritis in children.” Aliment Pharmacol Ther, 2019. https://pubmed.ncbi.nlm.nih.gov/31433527/
  3. Allen, A.P. et al. “Bifidobacterium longum 1714 as a translational psychobiotic.” Translational Psychiatry, 2016. https://pmc.ncbi.nlm.nih.gov/articles/PMC5143390/
  4. Szajewska, H. & Kolodziej, M. “Systematic review with meta-analysis: Saccharomyces boulardii in the prevention of antibiotic-associated diarrhoea.” Aliment Pharmacol Ther, 2015. https://pubmed.ncbi.nlm.nih.gov/26216624/
  5. Ouwehand, A.C. “A review of dose-responses of probiotics in human studies.” Beneficial Microbes, 2017. https://pubmed.ncbi.nlm.nih.gov/28008787/
  6. Saeed, M.A. et al. “Prebiotics and Gut Health: Mechanisms, Clinical Evidence, and Future Directions.” PMC, 2025. https://pmc.ncbi.nlm.nih.gov/articles/PMC12899272/
  7. Nguyen, T.T.B. et al. “Effects of probiotics, prebiotics, and synbiotics on gut microbiota in older adults: a systematic review and meta-analysis of randomized controlled trials.” PMC, 2025. https://pmc.ncbi.nlm.nih.gov/articles/PMC12482033/
  8. Sanders, M.E. et al. “Probiotics and prebiotics in intestinal health and disease.” Nat Rev Gastroenterol Hepatol, 2019. https://pubmed.ncbi.nlm.nih.gov/31296969/
  9. Zuccotti, G. et al. “Probiotics for prevention of atopic diseases in infants: systematic review and meta-analysis.” Allergy, 2015. https://pubmed.ncbi.nlm.nih.gov/26198702/
  10. Ducrotté, P. et al. “Clinical trial: Lactobacillus plantarum 299v (DSM 9843) improves symptoms of irritable bowel syndrome.” World J Gastroenterol, 2012. https://pubmed.ncbi.nlm.nih.gov/22969234/
  11. Grin, P.M. et al. “Lactobacillus for preventing recurrent urinary tract infections in women: meta-analysis.” Can J Urol, 2013. https://pubmed.ncbi.nlm.nih.gov/23930605/
  12. Hao, Q. et al. “Probiotics for preventing acute upper respiratory tract infections.” Cochrane Database Syst Rev, 2015. https://pubmed.ncbi.nlm.nih.gov/25927096/
  13. Govender, M. et al. “A Review of the Advancements in Probiotic Delivery: Conventional vs. Non-conventional Formulations.” AAPS PharmSciTech, 2014. https://pmc.ncbi.nlm.nih.gov/articles/PMC3969478/
  14. Malavolta, M. et al. “Bacillus coagulans: a viable adjunct therapy for relieving symptoms of IBS.” BMC Gastroenterol, 2020. https://pubmed.ncbi.nlm.nih.gov/32560623/
  15. Zhou, H. et al. “Differential effects of inulin and fructooligosaccharides on gut microbiota.” RCT, 2025. https://pmc.ncbi.nlm.nih.gov/articles/PMC12219383/
  16. Ford, A.C. et al. “Efficacy of Prebiotics, Probiotics, and Synbiotics in Irritable Bowel Syndrome.” Am J Gastroenterol, 2018. https://pubmed.ncbi.nlm.nih.gov/30066023/
  17. Hadi, A. et al. “Effects of probiotics, prebiotics and synbiotics on anthropometric, cardiometabolic and inflammatory markers.” Clinical Nutrition, 2024. https://doi.org/10.1016/j.clnu.2024.05.015
  18. Pandey, K.R. et al. “Probiotics, prebiotics and synbiotics — a review.” J Food Sci Technol, 2015. https://pmc.ncbi.nlm.nih.gov/articles/PMC4648921/
  19. Labdoor. “Probiotic Rankings.” 2019. https://labdoor.com/rankings/probiotics
  20. Wastyk, H.C. et al. “Gut-microbiota-targeted diets modulate human immune status.” Cell, 2021. https://pmc.ncbi.nlm.nih.gov/articles/PMC8370348/
  21. Cryan, J.F. et al. “The Microbiota-Gut-Brain Axis.” Physiol Rev, 2019. https://pubmed.ncbi.nlm.nih.gov/31460832/
  22. Davani-Davari, D. et al. “Prebiotics: Definition, Types, Sources, Mechanisms, and Clinical Applications.” Foods, 2019. https://pmc.ncbi.nlm.nih.gov/articles/PMC6463098/
  23. Guarino, M.P.L. et al. “Mechanisms of Action of Prebiotics and Their Effects on Gastro-Intestinal Disorders.” Nutrients, 2020. https://pmc.ncbi.nlm.nih.gov/articles/PMC7400611/
  24. Akkasheh, G. et al. “Clinical and metabolic response to probiotic administration in patients with MDD.” Nutrition, 2016. https://pubmed.ncbi.nlm.nih.gov/26706022/
  25. Markowiak, P. & Slizewska, K. “Effects of Probiotics, Prebiotics, and Synbiotics on Human Health.” Nutrients, 2017. https://pmc.ncbi.nlm.nih.gov/articles/PMC5622781/

Further Reading

© HealthSecrets.com — Evidence-based health guides. For informational purposes only. Not medical advice.