Quick Answer
If you have histamine intolerance or suspect histamine issues with SIBO, certain probiotic strains can make your symptoms worse. The key is knowing which strains produce histamine versus which strains are neutral or help break it down.
Histamine-producing strains to AVOID:
- Lactobacillus casei
- Lactobacillus delbrueckii subsp. bulgaricus
- Lactobacillus helveticus
- Lactobacillus reuteri (most strains, except DSM 17938)
- Lactobacillus bulgaricus
Histamine-safe or histamine-degrading strains:
- Bifidobacterium infantis
- Bifidobacterium longum
- Lactobacillus plantarum (especially 299v strain)
- Lactobacillus rhamnosus
- Saccharomyces boulardii (beneficial yeast)
The Problem: Not All Probiotics Are Created Equal
Some bacteria possess the genes to produce histidine decarboxylase, which converts histidine into histamine. Research analyzing the Human Microbiome Project found that "out of 349 reference genomes, only four genomes (all Lactobacillus) contained the complete histidine decarboxylase gene cluster" (PMC3285189).
Histamine-Producing Strains: What to Avoid
Lactobacillus casei
Found in many commercial probiotics and fermented dairy products. Documented histamine-producing strains.
Lactobacillus bulgaricus
One of the traditional yogurt starter cultures. Well-documented histamine producer.
Lactobacillus helveticus
Used in cheese fermentation and some supplements. Strong histamine producer.
Lactobacillus reuteri
Complicated case: some strains are therapeutic, others produce histamine. Research shows that "histamine production appears to be a host-specific trait as only L. reuteri strains isolated from human hosts possess the histidine decarboxylase gene" (PMC3285189). Exception: DSM 17938 may be well-tolerated.
Histamine-Safe Strains: What to Choose
Bifidobacterium infantis
Well-studied for IBS and gut health. Bifidobacterium species generally lack histidine decarboxylase genes.
Bifidobacterium longum
Histamine-neutral. May support gut barrier function.
Lactobacillus plantarum 299v
One of the most researched strains. Well-tolerated in histamine-sensitive individuals.
Lactobacillus rhamnosus GG
Generally histamine-neutral. One of the most studied probiotic strains.
Saccharomyces boulardii
A beneficial yeast. Doesn't produce histamine.
Practical Selection Guide
Before buying a probiotic, check the label for strain-specific information. If a label just says "Lactobacillus blend" without strain numbers, don't buy it. Start with single-strain products from the safe list and monitor your response.
Key Takeaways
- Not all probiotics are safe for histamine intolerance
- Avoid: L. casei, L. bulgaricus, L. helveticus, L. reuteri (most strains)
- Safe: B. infantis, B. longum, L. plantarum 299v, L. rhamnosus GG, S. boulardii
- Always check for strain-specific labeling
Medical disclaimer: This article is educational only. If you have severe histamine reactions, seek medical care immediately.