Probiotics
Various strains (Lactobacillus, Bifidobacterium, Saccharomyces)
Probiotics are live microorganisms that, when consumed in adequate amounts, provide health benefits. Different strains have different effects – from digestive support to immune modulation to mood improvement via the gut-brain axis. Strain specificity is crucial when matching a probiotic to a health goal.
How It Works
Probiotics work through multiple mechanisms:
- Competitive Exclusion: Compete with pathogens for adhesion sites and nutrients in the gut.
- Antimicrobial Production: Produce bacteriocins, organic acids, and hydrogen peroxide that inhibit pathogens.
- Gut Barrier: Strengthen tight junctions between intestinal cells, reducing intestinal permeability (“leaky gut”).
- Immune Modulation: Interact with gut-associated lymphoid tissue (GALT), training and modulating immune responses.
- Metabolite Production: Produce short-chain fatty acids (SCFAs) that nourish colonocytes and have systemic anti-inflammatory effects.
- Neurotransmitter Production: Some strains produce GABA and serotonin precursors, influencing mood via the gut-brain axis.
Key Benefits
- Digestive health: Strong evidence for antibiotic-associated diarrhea and some IBS cases (strain-specific).
- Immune function: Improving certain immune responses and reducing infection risk in some contexts.
- Gut-brain axis: Emerging evidence for benefits in anxiety and depression with specific strains.
- Women’s health: Some strains help prevent or manage bacterial vaginosis and yeast infections.
Benefits are strain-specific, not generic to all probiotics.
How Probiotics are Used
- General gut support: 1–10 billion CFU/day of well-studied Lactobacillus/Bifidobacterium blends.
- Targeted therapeutic uses (e.g., IBS, AAD): 10–100 billion CFU/day, or specific S. boulardii doses (250–500 mg), over weeks to months.
- With antibiotics: Dosing at least 2 hours away from the antibiotic and continuing for 1–2 weeks after the course.
Choice of strain and dose should match the studied indication whenever possible.
Natural Food Sources
| Food | Amount per Serving |
|---|---|
| Yogurt | 1-10 billion CFU per serving (varies) |
| Kefir | 10-34 billion CFU per cup |
| Kefir | ~1 billion CFU per 1/2 cup |
| Sauerkraut (raw, unpasteurized) | Variable, billions per serving |
| Kimchi | Variable, often lower than supplements |
| Kombucha | Variable |
Safety Information
Contraindications
- Severe immunocompromise – risk of bacteremia/fungemia
- Central venous catheters - rare infection risk
- Central venous catheters – rare risk of bloodstream infection
Potential Side Effects
- Gas and bloating (usually temporary as gut microbiota adjusts) (common)
- Mild GI upset (common)
- Mild GI upset (uncommon)
Scientific Research
Probiotics and Anxiety/Depression: A Systematic Review
Journal of Affective Disorders
This review of 34 studies found that probiotic supplements can help reduce both anxiety and depression symptoms, supporting the “gut-brain connection” theory. The benefits were more pronounced in people with clinical anxiety or depression compared to healthy individuals. Taking multi-strain probiotics for at least 8 weeks appears most effective. Scientists believe gut bacteria influence brain chemistry through various pathways including the vagus nerve and immune system.
Probiotics for IBS: A Systematic Review and Network Meta-Analysis
The Lancet Gastroenterology & Hepatology
This large analysis of 53 studies confirmed that probiotics are effective for treating irritable bowel syndrome (IBS). Multi-strain probiotics containing Lactobacillus and Bifidobacterium bacteria worked best. About 1 in 7 people with IBS who take probiotics will see significant improvement that wouldn’t have occurred with placebo. Both diarrhea-predominant and constipation-predominant IBS responded to treatment.
Recommended Products
Garden of Life RAW Probiotics Ultimate Care
Garden of Life
Disclaimer: The information provided is for educational purposes only and is not intended to diagnose, treat, cure, or prevent any disease. Always consult with a qualified healthcare provider before starting any supplement regimen.