Supplements to reduce IL-17

The interleukin 17 (IL-17) family, a subset of cytokines plays crucial roles in both acute and chronic inflammatory responses. Its intended role is against pathogens — but if it is stuck on then it becomes harmful. This can sometime happen with mis-identification of chemical signals. For details on the members of this subset, see Kyoto Encyclopedia of Genes and Genomes.

It appears to be a significant player for Autism, Interleukin-17 in Chronic Inflammatory Neurological Diseases [2020]

A reader has asked about items that are known to reduce it. The following comes from a search of PubMed

  • There are a variety of prescription IL-17 inhibitors (ixekizumab, secukinumab, bimekizumab, netakimab, brodalumab) covered in this review [2021]
  • An engineered Lactobacillus salivarius  is described here [2017]
  • Lactobacillus plantarum (LP) IS-10506 “The IL-4 and IL-17 levels were significantly lower in the probiotic than the placebo group.” [2020]
  • Luteolin decreases levels [2021] (available as a supplement)
  • ” The combination of L. acidophilus, vitamin B, and curcumin effectively downregulated Th17 cells and the related cytokine IL-17, thereby maintained the Treg population, ” [2020]
  • Lactobacillus plantarum “pre-treatment with food-borne Lpb. plantarum significantly reduce pro-inflammatory cytokines IL-17F and IL-23 levels in inflamed NCM460 cells.” [2020]
  • Lactobacillus casei Shirota (Yakult, the beverage) ” LcS significantly reduced plasma monocyte chemotactic protein-1 and, on subgroup analysis, plasma interleukin-1β (alcoholic cirrhosis), interleukin-17a and macrophage inflammatory protein-1β (non-alcoholic cirrhosis), compared with placebo.” [2020]
  • The Role of Flavonoids in Inhibiting Th17 Responses in Inflammatory Arthritis [2018] provide a lot of details (including some unusual herbs and spices). Items more commonly available include:
    • Apples –  Procyanidins B1, B2, and C1
    • Grape Seed Extract — Proanthocyanidins
    • Licorice — (Glycyrrhiza glabra) I can strongly attest that it does wonders for inflammation (We use spezzatina )
    • Blueberry, Raspberry, black rice, and black soybean – Anthocyanins
  • Berberine “attenuating the Th17 response triggered by the B cell-activating factor” [2018]
  • Astragalus “Downregulating Interleukin-17 Expression via Wnt Pathway'[2020]
  • Curcumin (Turmeric) – “Curcumin mediates attenuation of pro-inflammatory interferon γ and interleukin 17 cytokine responses in psoriatic disease” [2020]

More items (with references) is listed here, this was a quick summary – that is a deeper review.

To avoid:

  • Lactobacillus rhamnosus GG (LGG) ATCC 53103 “upregulated the expression of IL-17” [2020]
  • “We confirm that food intake increases IL-17 expression in the mouse ileum and human blood. e. Thus, IL-17 is a gut-produced factor that is controlled by diet and modulates food intake by acting in the hypothalamus. Our findings provide the first evidence of a cytokine that is acutely regulated by food intake and plays a role in the regulation of eating.” [2020]

Bottom Line

The last citation points to the microbiome as a very significant factor for the levels of IL-17. At present, we do not know which bacteria play a role (many bacteria cannot be cultured, which limits our knowledge of what they do).

Modelling Candidate Bacteria

We have a list of items that reduces IL-17. We also find many of these items in our database. Thus if we look at the bacteria that are reduced by these food, we may be able to generate a candidate list of bacteria of concern.

The result is this list of significant bacteria

  • Clostridiaceae (family)
  • Enterobacteriaceae (family)
  • Staphylococcaceae (family)
  • Streptococcaceae (family)
  • Clostridium (genus)
  • Enterobacter (genus)
  • Enterococcus (genus)
  • Escherichia (genus)
  • Kluyvera (genus)
  • Pseudomonas (genus)
  • Staphylococcus (genus)
  • Streptococcus (genus)
  • Enterococcus faecalis (species)
  • Escherichia coli (species)
  • Pseudomonas aeruginosa (species)
  • Pseudomonas aeruginosa group (species)
  • Staphylococcus aureus (species)
  • Streptococcus mutans (species)

The strongest hint is for Staphylococcus aureus (species) which leads to this article:

So we have a full cycle… items shown to reduce IL-17 also are items that reduce a list of bacteria. Checking those bacteria, we find that they are associated with high IL-17 levels.

Consequence: In asking for suggestions – you may wish to go to hand-pick bacteria and select any of those listed above.

I have a longer list by genus below that are also suspect (from strongest hint to weaker).

  1. Escherichia (genus)
  2. Pseudomonas (genus)
  3. Staphylococcus (genus)
  4. Kluyvera (genus)
  5. Streptococcus (genus)
  6. Enterobacter (genus)
  7. Clostridium (genus)
  8. Enterococcus (genus)
  9. Citrobacter (genus)
  10. Dorea (genus)
  11. Eubacterium (genus)
  12. Raoultella (genus)
  13. Shigella (genus)
  14. Bacillus (genus)
  15. Fenollaria (genus)
  16. Intestinimonas (genus)
  17. Caloramator (genus)
  18. Oscillibacter (genus)
  19. Gracilibacter (genus)
  20. Coprobacter (genus)
  21. Slackia (genus)
  22. Helicobacter (genus)
  23. Coprococcus (genus)
  24. Cronobacter (genus)
  25. Prevotella (genus)
  26. Anaerobutyricum (genus)
  27. Parasporobacterium (genus)
  28. Anaerobium (genus)
  29. Anaerotignum (genus)
  30. Fusicatenibacter (genus)
  31. Hespellia (genus)
  32. Faecalicatena (genus)
  33. Tyzzerella (genus)

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