Probiotics (Multi-Strain)

Mechanism of Action

Multi-strain probiotics colonize the gut mucosa and exert effects via multiple mechanisms: competitive exclusion of pathogens, production of short-chain fatty acids (butyrate, propionate, acetate) via fermentation of prebiotic fibers, strengthening of intestinal tight junctions (via occludin and zonulin modulation), modulation of gut-associated lymphoid tissue (GALT, ~70% of immune system), production of bacteriocins (antimicrobial peptides), and bidirectional gut-brain axis signaling via the vagus nerve affecting serotonin, GABA, and BDNF levels.

Dosing Protocol

Notes

Strain specificity is paramount — different strains have entirely different clinical effects. L. rhamnosus GG for diarrhea prevention; B. infantis 35624 for IBS; L. reuteri for cardiovascular and testosterone; S. boulardii for C. difficile prevention. Histamine-producing strains (L. casei, L. reuteri, L. bulgaricus) should be avoided in histamine-intolerant clients. GI mapping (GI-MAP or similar) before and after can quantify impact. Consider spore-based probiotics for clients who don't respond to traditional strains.

Stacking

• Prebiotics (FOS, GOS, inulin)
• Digestive Enzymes
• L-Glutamine
• Saccharomyces boulardii

Interactions

• Antibiotics [MEDIUM] — Antibiotics kill probiotic organisms — separate dosing by 2+ hours; continue probiotics 2 weeks post-antibiotic course
• Immunosuppressants [MEDIUM] — Probiotic organisms could theoretically cause infection in severely immunocompromised patients
• Antifungals [LOW] — May affect Saccharomyces boulardii if included in the probiotic

Contraindications

• Severe immunosuppression (risk of probiotic bacteremia/fungemia)
• Short bowel syndrome
• Central venous catheter (risk of Saccharomyces translocation)
• Acute pancreatitis (PROPATRIA trial warning)

Side Effects

• Bloating/gas (usually transient, 1-2 weeks)
• Mild diarrhea during adjustment
• Brain fog or D-lactic acidosis (rare, with Lactobacillus overgrowth)
• Histamine intolerance flare (strain-dependent)

Key Papers

• 10.1038/s41575-019-0173-3
• 10.1016/j.cell.2018.08.041
• 10.1016/j.cgh.2015.01.031

Source Quality

Strain-specific evidence matters — look for specific strain designations (e.g., L. rhamnosus GG, B. lactis Bi-07), not just species. CFU count at expiration, not manufacture. Delayed-release capsules for acid protection. Refrigerated products may have higher viability. Spore-based probiotics (Bacillus subtilis, B. coagulans) survive stomach acid without enteric coating. Brands: Seed DS-01, VSL#3 (prescription strength), Visbiome, Thorne FloraPro-LP.

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