Histamine-Degrading Bacteria
Some gut bacteria metabolize Histamine rather than producing it, effectively reducing the histamine load in the gut lumen. Supporting these populations is a potential strategy for managing Histamine Intolerance and reducing one input to Total Mediator Load.
Known Histamine-Degrading or Histamine-Neutral Species
- Bifidobacterium infantis — generally considered histamine-degrading and anti-inflammatory. One of the most commonly recommended genera for histamine-sensitive individuals.
- Bifidobacterium longum — histamine-neutral to histamine-degrading
- Lactobacillus rhamnosus GG — histamine-neutral (does not produce histamine, despite being a Lactobacillus)
- Lactobacillus plantarum — generally histamine-neutral, some strains may degrade histamine
- Lactobacillus salivarius — histamine-neutral
Mechanism
Histamine degradation by gut bacteria uses bacterial diamine oxidase (a microbial analog of human DAO) or histamine N-methyltransferase to metabolize histamine in the gut lumen before it can be absorbed.
Practical Application
When choosing probiotics in the context of mast cell conditions:
- Avoid strains known to produce histamine (see Histamine-Producing Bacteria)
- Favor Bifidobacterium-dominant formulations
- Research at the strain level when possible — species-level generalizations are insufficient
- Introduce slowly and monitor, because even theoretically safe strains can shift the microbiome in unpredictable ways
Supporting endogenous histamine-degrading bacteria through prebiotic fiber (feeding them) may be as important as introducing them through supplementation. See SCFAs and Butyrate.