Medical Disclaimer: Supplements are not regulated like drugs. Third-party testing (NSF, USP, Informed Sport) is essential. Consult a healthcare provider before starting, especially if pregnant, nursing, on medications, or have IBD/immunocompromise.
Grading System
| Grade | Definition | Action |
|---|---|---|
| A | Multiple RCTs, meta-analyses, consistent benefit, clear dosing | Use for indicated condition |
| B | Several RCTs, some inconsistency, or condition-specific benefit | Consider for indicated condition |
| C | Limited human data, mechanistic plausibility, small studies | Experimental; low priority |
| D | No human RCTs, negative trials, or theoretical only | Don’t waste money |
| F | Harmful, contaminated, or fraudulent claims | Avoid entirely |
Grade A: Strong Evidence
1. Psyllium Husk (Soluble Viscous Fiber)
| Indication | Dose | Evidence | Best Form |
|---|---|---|---|
| Chronic constipation | 10–20g/day (split) | Meta-analyses: ↑ stool frequency, ↓ straining | Husk powder (cheaper) or capsules |
| IBS-C / IBS-M | 10g/day | RCTs: superior to wheat bran, fewer side effects | Organic, no additives |
| LDL cholesterol | 10–15g/day | FDA health claim: 7g/day → ↓ CHD risk | Same |
| Glycemic control | 5–10g with meals | ↓ postprandial glucose 15–20% | Same |
Start: 3g/day → +3g/week. Water: 250ml per 5g. Brands: NOW, Yerba Prima, generic (test for heavy metals).
2. PHGG (Partially Hydrolyzed Guar Gum / Sunfiber®)
| Indication | Dose | Evidence | Advantage |
|---|---|---|---|
| IBS (all subtypes) | 5–10g/day | RCTs: ↓ pain, ↓ bloating, normalizes stool | Low gas, well-tolerated, prebiotic |
| SIBO adjunct | 5g/day during/after abx | Small RCTs: ↓ recurrence with rifaximin | Feeds colonic, not small bowel |
| Post-antibiotic recovery | 5–10g/day × 8 weeks | ↑ Bifidobacterium, ↑ butyrate | Better tolerated than inulin |
| Pediatric constipation | 3–5g/day | RCTs: safe, effective in children | Tasteless, dissolves clear |
Brands: Sunfiber® (patented), Regular Girl®, Tomorrow’s Nutrition®. Look for “Sunfiber” on label.
3. Saccharomyces boulardii (Probiotic Yeast)
| Indication | Dose | Evidence | Key Advantage |
|---|---|---|---|
| Antibiotic-associated diarrhea (AAD) | 250–500mg 2x/day | Cochrane: ↓ AAD 50–60%, ↓ C. diff 60% | Survives antibiotics (yeast) |
| C. difficile prevention | 500mg 2x/day | Meta-analysis: NNT = 29 | Standard of care adjunct |
| Traveler’s diarrhea | 250mg 2x/day (start 5 days before) | RCTs: ↓ incidence 15–20% | Heat-stable (no refrigeration) |
| H. pylori eradication adjunct | 500mg 2x/day × 14d | ↑ eradication rate, ↓ side effects | Doesn’t interfere with antibiotics |
Brands: Florastor® (patented CNCM I-745), Jarrow, Thorne. Must be S. boulardii CNCM I-745 or equivalent.
4. Lactobacillus rhamnosus GG (LGG)
| Indication | Dose | Evidence | Population |
|---|---|---|---|
| AAD prevention | 10–20B CFU/day | Grade A (pediatric strongest) | Children, adults |
| Acute infectious diarrhea | 10B CFU 2x/day | ↓ duration 1 day (Cochrane) | Children |
| Pediatric atopic dermatitis prevention | 10B CFU/day (maternal + infant) | ↓ incidence 50% (high-risk) | Pregnancy + infancy |
Brands: Culturelle® (patented GG), Garden of Life, NOW. Must specify “L. rhamnosus GG” — not just “L. rhamnosus.”
Grade B: Moderate Evidence
5. Bifidobacterium longum 35624 (Align® Strain)
IBS (bloating, pain): 1B CFU/day. Multiple RCTs: ↓ bloating, ↓ abdominal pain vs. placebo. Only this strain — other B. longum strains not equivalent.
6. Probiotic Multi-Strain (Specific Formulations Only)
VSL#3 / Visbiome® (8 strains, 450–900B CFU): Ulcerative colitis pouchitis, hepatic encephalopathy — Grade A. Expensive, requires refrigeration.
Bio-K+ (L. acidophilus CL1285 + L. casei LBC80R): AAD, C. diff — Grade B.
General multi-strains: Grade C — strain specificity matters; “10 strains 50B CFU” marketing ≠ evidence.
7. Prebiotic Fibers (Inulin, FOS, GOS, Resistant Starch)
| Fiber | Dose | Best For | Tolerance |
|---|---|---|---|
| Inulin (chicory) | 3–10g/day | ↑ Bifidobacterium, constipation | High gas at >5g |
| FOS | 2–8g/day | Similar to inulin | High gas |
| GOS (Bimuno®) | 2–5g/day | ↑ Bifido, IBS (some) | Moderate gas |
| Resistant Starch (potato, green banana) | 10–20g/day | ↑ Butyrate, insulin sensitivity | Best tolerated fermentable |
8. Digestive Enzymes
| Enzyme | Indication | Dose | Evidence |
|---|---|---|---|
| Lactase | Lactose intolerance | 3000–9000 FCC units/meal | A |
| Pancreatin (lipase/amylase/protease) | Pancreatic insufficiency (CF, chronic pancreatitis, post-Whipple) | 25,000–50,000 USP units lipase/meal | A |
| Alpha-galactosidase (Beano®) | Bean/vegetable gas | 300–600 GALU/meal | B |
| Glutenase (AN-PEP) | Accidental gluten exposure (NOT for celiac) | Per product | C |
Grade C: Limited / Conditional Evidence
- L-Glutamine: Post-infectious IBS, critical illness, chemotherapy mucositis. Not for “leaky gut” in healthy people. Dose: 5–15g/day.
- Zinc Carnosine (PepZin GI®): Gastritis, H. pylori adjunct, NSAID protection. 75mg 2x/day. Small RCTs promising.
- Deglycyrrhizinated Licorice (DGL): Functional dyspepsia, GERD symptom relief. Chewable 380mg before meals. Mechanistic + small studies.
- Slippery Elm / Marshmallow Root / Aloe: Mucilaginous demulcents. Theoretical barrier support. No human RCTs for gut healing.
- Butyrate (Tributyrin / Sodium Butyrate): Ulcerative colitis adjunct, radiation proctitis. Emerging; delivery to colon is challenge. 300–900mg/day.
- Betaine HCl: Only for confirmed hypochlorhydria (Heidelberg test). Risk if H. pylori/ulcer. Dose titration required.
Grade D: No Evidence / Waste of Money
- “Leaky Gut Repair” blends: Proprietary mixes of glutamine, zinc, quercetin, NAG, DGL — no RCTs on the blend.
- Soil-Based Organisms (SBOs) / Spore Probiotics: Marketing > evidence. Safety concerns (bacteremia in immunocompromised). No advantage over Lacto/Bifido.
- Colostrum for “gut healing”: No human RCTs for intestinal permeability in adults. Expensive.
- Bone broth / collagen for “gut lining”: Glycine/proline for connective tissue, but no RCTs showing gut barrier repair in healthy humans.
- Digestive bitters: Theoretical vagal stimulation. No RCTs for functional GI disorders.
- Activated charcoal for “bloating”: Binds nutrients/meds. Emergency use only (poisoning).
Grade F: Harmful / Fraudulent
- MMS (Miracle Mineral Solution / Chlorine Dioxide): Industrial bleach. Causes severe GI injury, methemoglobinemia, death. Marketed for “parasites,” “autism,” “COVID.” Illegal, dangerous.
- Parasite “cleanse” protocols (wormwood, black walnut, clove) without diagnosis: Hepatotoxic, neurotoxic herbs. No evidence for “rope worms” (which are mucus).
- Hydrogen peroxide “therapy” (oral/IV): Gas embolism, GI perforation, hemolysis. Never ingest.
- Coffee enemas: Electrolyte imbalance, rectal burns, sepsis, death. No detox benefit.
- Unregulated “gut health” MLM products with income claims: Violation of DSHEA/FTC.
Decision Matrix: Which Supplement for Your Symptom?
| Primary Symptom | First-Line (Grade A/B) | Second-Line (Grade B/C) | Avoid |
|---|---|---|---|
| Constipation | Psyllium 10–20g/d, PHGG 5–10g/d | PEG 3350, Magnesium glycinate 400mg | Senna daily, “colon cleanse” teas |
| Diarrhea (acute) | S. boulardii 500mg 2x/d, L. rhamnosus GG 20B/d | Loperamide PRN, Bismuth subsalicylate | Activated charcoal, random probiotics |
| Antibiotic protection | S. boulardii + L. rhamnosus GG (start day 1) | VSL#3 if high-risk | Random multi-strain during abx |
| IBS Bloating | PHGG 5g/d, B. longum 35624 (Align) | Peppermint oil EC, Low FODMAP | Inulin, FOS, random probiotics |
| IBS Constipation | Psyllium 10g/d, Linaclotide (Rx) | PHGG + Magnesium, Prucalopride (Rx) | Stimulant laxatives daily |
| SIBO | Rifaximin (Rx) + Prokinetic (Rx) | Elemental diet, Herbal antimicrobials | Probiotics during treatment (controversial) |
| Post-antibiotic recovery | Fermented foods 2x/d + PHGG 5g/d + 30 plants/wk | S. boulardii 2 weeks post | “Gut repair” blends, bone broth protocols |
| Lactose intolerance | Lactase enzyme with dairy | Lactose-free dairy, fermented dairy | “Gut health” supplements for this |
| General “optimization” | 30 plants/week, fermented foods, sleep, movement | None needed if above done | Daily multi-strain probiotic, “greens” for gut |
How to Choose a Quality Supplement
- Third-party tested: NSF Certified for Sport, USP Verified, Informed Sport, ConsumerLab.
- Strain-specific: Label lists genus, species, strain (e.g., Lactobacillus rhamnosus GG not just L. rhamnosus).
- CFU at expiration: Not “at manufacture.” Probiotics die over time.
- No proprietary blends: Every ingredient + dose disclosed.
- Appropriate form: Enteric-coated for probiotics (some), delayed-release for butyrate, chelated minerals.
References
- Hempel S, et al. “Probiotics for AAD.” JAMA. 2012;307(18):1959-1969.
- Goldenberg JZ, et al. “Probiotics for C. diff Prevention.” Cochrane. 2017.
- Ford AC, et al. “Efficacy of Probiotics in IBS.” Am J Gastroenterol. 2018;113(7):1011-1022.
- McFarland LV. “Meta-analysis of Probiotics for AAD.” Travel Med Infect Dis. 2015.
- Staudacher HM, et al. “Low FODMAP Diet for IBS.” Gastroenterology. 2017.
- Outcomes Research Consortium. “PHGG for IBS.” Nutrients. 2020.
