In an earlier post, I had illustrate the problem of whether L.Reuteri produced histamine. The answer is “Not sufficient information to answer” — why is shown below. It depends on which strain you have! The source (human/not human) is not sufficient. In general, the probiotic species is insufficient to answer the histamine question.

• Individual strains of Lactobacillus paracasei differentially inhibit human basophil and mouse mast cell activation [2016] “Thus, L. paracasei CNCM I‐1518 could not only inhibit mouse mast cell and human basophil activation 19, but also protect mice from Salmonella Typhimurium infection 31, induce regulatory T cells in skin inflammation model 32, and improve allergic rhinitis in children 33. These studies, which focused on one or a few strains of bacteria, did not permit an accurate comparison of the effects of different bacterial strains.“

Lactobacillus Casei and Paracasei

On many studies, this is reported to reduce hay fever and allergies. If you check the web, you will find that it is also reported as a histamine producer. How can this be true since increased histamines would make allergies worst. The answer is simple. BOTH ARE CORRECT when you look at the fine print… (and you need the fine print that may be missing on the probiotic label).

• “histamine production were found in … Lactobacillus casei 18, isolated from cider)” [2013]
• “According to the results,  Lactobacillus casei CCDM 198 exhibited the best degradation abilities…. significantly (P < 0.05) reduced BAs (putrescine, histamine, tyramine, cadaverine), up to 25% decline in 48 h.” [2020]
• ” Lb. paracasei subsp. paracasei CB9CT and another strain (CACIO6CT) of the same species that was able to degrade all the BAs were singly used as adjunct starters for decreasing the concentration of histamine ” [2016]
• “Seventeen isolates were found that were able to degrade tyramine and histamine in broth culture. All 17 isolates were identified by 16S rRNA sequencing as belonging to Lactobacillus casei.” [2012]

For Lb Casei and Paracasei, most of the studies suggests that it degrades histamine.

Worked Example

We use L. Casi and L. Paracasei from Custom Probiotics, for two main reasons, they are the cheapest per BCFU, they have no fillers, pre-biotics, etc so we do not have to deal with counter-indicated formulation that often happens with commercial probiotics blends (often using a marketing-driven formulation).

So looking up the strains, I see Lc-11 and Lpc-37, Time to search for information on these:

On LPC-37

• Lacticaseibacillus paracasei Lpc-37® improves psychological and physiological markers of stress and anxiety in healthy adults: a randomized, double-blind, placebo-controlled and parallel clinical trial (the Sisu study) [2020]
• The immune system in healthy adults and patients with atopic dermatitis seems to be affected differently by a probiotic intervention [2008] use Lpc-37
• The influence of Lactobacillus Paracasei LPC-37 on selected properties of fermented sausages [2015]

On Lc-11

• Obesity and gut microbiome: review of potential role of probiotics [2021] “In obese women, the administration of a probiotic mix composed of L acidophilus LA-14, L casei LC-11, L lactis LL-23, and B bifidum BB–06, improved BW composition after an 8-week supplementation period. A”
• Title: Enumeration of probiotic strain Lactobacillus casei Lc-11 using viability real time PCR [2019]
• I also found this table that is helpful for those taking antibiotics.
  

Bottom Line

IMHO, you need to:

• Know every strain in your probiotics (not just species!)
• You need to be able to locate studies using that strains (Lb. Casei Snakeoild may be just a marketing name to hide that fact that the manufacturer/packager does not know the strain)
  • I have seen some product literature claiming benefits from a different strain because they were the same species —FALSE LOGIC.
• Ideally, you will find some relevant studies using these strains — ideally on humans!

If you are using antibiotics, you may wish to search for the probiotics antibiogram. Ideally, the manufacturer/seller would provide all of that information with a simple email requesting it.