Probiotics
What is it?
Probiotics are live microorganisms that, when administered in adequate quantities, confer health benefits to the host. The human intestinal microbiome is composed of trillions of microorganisms — mostly bacteria — that influence digestion, immunity, vitamin synthesis, neurotransmitters and even mood. Probiotic supplementation aims to enrich and balance this microbiota, especially after dysbiosis (imbalance) caused by antibiotics, poor diet, stress or disease. Strain, dose and quality are the most critical factors — there is no effective 'generic probiotic'.
Main Benefits
- Intestinal microbiota balance
- Improved digestion and reduction of IBS (irritable bowel syndrome) symptoms
- Immune support — 70–80% of the immune system is in the intestine
- Reduction of duration of infectious and post-antibiotic diarrheas
- Possible mood and anxiety improvement (gut-brain axis)
- Vaginal health support (Lactobacillus)
- May improve nutrient absorption
Who it's for
- •People using or who recently used antibiotics
- •People with dysbiosis, IBS or irritable bowel
- •People with low immunity or recurrent infections
- •Women with history of candidiasis or vaginal infections
- •People with anxiety or unstable mood (gut-brain axis)
- •People with diets poor in fiber and fermented foods
- •Travelers susceptible to traveler's diarrhea
Common Dose
1–10 billion CFU (Colony Forming Units) for general use. 10–50 billion CFU for specific conditions or post-antibiotics. Take fasted or 30 minutes before meals — less exposure to gastric acid. Always check expiration date and storage conditions.
Available Types
Lactobacillus spp.
Characteristics
- •Most studied genus of probiotics
- •Colonizes mainly the small intestine and vagina
- •Produces lactic acid — acidifies the environment and inhibits pathogens
- •Most studied strains: L. acidophilus, L. rhamnosus GG, L. reuteri
Pros
- Most studied with the greatest variety of documented strains
- Excellent for vaginal and digestive health
- L. rhamnosus GG has evidence for diarrhea in children and adults
Cons
- Strain-dependent efficacy — not all Lactobacillus have the same effect
Best for
- Vaginal health and candidiasis
- Diarrhea and digestion
- General preventive use
Bifidobacterium spp.
Characteristics
- •Colonizes mainly the large intestine (colon)
- •Important for fiber fermentation and production of short-chain fatty acids (SCFA)
- •Declines with age — especially after 60 years
- •Most studied strains: B. longum, B. lactis, B. breve
Pros
- Fundamental for colon health
- Produces SCFA — intestinal cell nutrition
- Important for immunity and inflammation reduction
- Mood support via gut-brain axis
Cons
- Strain-dependent efficacy
- More sensitive to stomach acid environment than Lactobacillus
Best for
- Colon health and constipation
- Immunity and intestinal inflammation
- People over 50 with natural Bifidobacterium decline
Saccharomyces boulardii
Characteristics
- •Probiotic yeast — not a bacterium
- •Antibiotic resistant — can be used simultaneously
- •Excellent evidence for antibiotic-associated diarrhea
- •Does not colonize permanently — acts transiently
Pros
- Can be used during antibiotic (resistant)
- Best evidence for traveler's diarrhea and post-antibiotic
- Resistant to gastric acid
- Evidence for H. pylori and Clostridium difficile
Cons
- Yeast — contraindicated in severely immunosuppressed
- Does not colonize permanently — transient effect
Best for
- Use during and after antibiotics
- Traveler's diarrhea
- Acute gastrointestinal infections
Multi-strain (10B+ CFU)
Characteristics
- •Combination of multiple strains of Lactobacillus and Bifidobacterium
- •Doses generally above 10 billion CFU
- •Action in multiple regions of the intestine
- •Greater microbial diversity in the supplement
Pros
- Broader microbiome coverage
- Synergistic action between strains
- Better for general use and broad dysbiosis
Cons
- Higher cost
- Interaction between strains can be unpredictable
- Check if all strains have individual evidence
Best for
- Broad dysbiosis after prolonged antibiotics
- General microbiota rebalancing
- Preventive use for complete intestinal health
Quick Comparison
| Strain/Type | Main focus | Best for | Use with antibiotic? |
|---|---|---|---|
| Lactobacillus | Small intestine and vagina | Digestion and vaginal health | No (sensitive) |
| Bifidobacterium | Colon and immunity | Constipation and immunity | No (sensitive) |
| Saccharomyces boulardii | Acute diarrhea | Antibiotics and travel | Yes (resistant) |
| Multi-strain | General microbiome | Broad dysbiosis | Partially |
How to Choose
Lactobacillus spp.
Choose if:
- You have recurrent candidiasis or vaginal infections
- You seek improved digestion in the small intestine
- You want general preventive use with a well-studied strain (L. rhamnosus GG)
Bifidobacterium spp.
Choose if:
- You have constipation or slow bowel
- You seek immune and intestinal anti-inflammatory support
- You are over 50 with natural Bifidobacterium decline
Saccharomyces boulardii
Choose if:
- You are taking or just finished antibiotics
- You are traveling to regions with diarrhea risk
- You have an acute gastrointestinal infection
Multi-strain (10B+ CFU)
Choose if:
- You underwent prolonged antibiotic therapy
- You want to broadly rebalance the microbiota
- You seek complete preventive support for the microbiome
What the Science Says
Probiotics have solid evidence for specific conditions — especially antibiotic-associated diarrhea (L. rhamnosus GG and S. boulardii), IBS (multiple strains) and vaginal health (Lactobacillus). The gut-brain axis is an emerging area with promising studies for mood and anxiety. Evidence for immunity is moderate. The critical point: efficacy is strain-specific — results from a study with L. rhamnosus GG do not apply to another generic Lactobacillus.
Possible Side Effects
Gas and abdominal bloating in the first weeks — especially at high doses. Generally transient. In severely immunosuppressed (chemotherapy, transplant), rare but real risk of infection by probiotic microorganisms — use only under medical guidance. S. boulardii contraindicated with central venous catheter.
Final Summary
Probiotics are effective when the right strain is chosen for the right goal. S. boulardii for antibiotics and acute diarrhea; L. rhamnosus GG for digestion and vaginal health; Bifidobacterium for colon and immunity; multi-strain for broad dysbiosis. Always check the declared strain, dose in CFU and storage conditions. Prebiotics (fiber) enhance the effect of probiotics.