Take inulin for your brain

This 2023 rodent study investigated effects of inulin on gut microbiota and brain inflammation:

“Microglia are the first immune responders in the brain. Their activation leading to neuroinflammation can promote homeostasis, but if unchecked can be pathological.

We evaluated anti-inflammatory effects of short-chain fatty acids (SCFAs) on lipopolysaccharide (LPS)-stimulated microglia from mice fed inulin, a soluble fiber fermented by intestinal microbiota to produce SCFAs, and SCFAs applied to primary microglia in vitro:

  • Feeding mice inulin increased SCFAs in the cecum and in plasma collected from the hepatic portal vein.
  • Microglia isolated from mice fed inulin and stimulated with LPS in vitro secreted less tumor necrosis factor α (TNF-α) compared to microglia from mice not given inulin.
  • Mice fed inulin and injected i.p with LPS ex vivo secretion of TNF-α by isolated microglia was lower than that secreted by microglia from mice not fed inulin and injected with LPS.


in vitro treatment of primary microglia with acetate and butyrate either alone or in combination downregulated microglia cytokine production, with effects being additive. SCFAs reduced histone deacetylase activity and nuclear factor-κB nuclear translocation after LPS treatment in vitro.

If SCFAs produced in the gut regulate microglia directly, it is likely through an epigenetic mechanism following diffusion.”

https://www.nature.com/articles/s41598-022-27086-x “Inhibition of inflammatory microglia by dietary fiber and short-chain fatty acids”

Mice typically eat 4-5 grams of chow daily. A human equivalent of this study’s 2.5% inulin treatment would be:

  • (5,000 mg x .025) = 125 mg;
  • (125 mg x .081) = 10.125 mg;
  • (10.125 mg x 70 kg) = 709 mg.

A daily intake of < 1 gram of inulin isn’t very much. I take < 10 grams.



6 thoughts on “Take inulin for your brain

  1. Thanks. I was so close to ordering some Inulin and then I found this:
    Dietary Inulin Supplementation Affects Specific Plasmalogen Species in the Brain
    In this study, we showed that dietary supplementation with inulin do not modify the global amount of Pls in the cortex of mice but affects its content at the species level. In particular, dietary intake of this prebiotic induces a decrease in the abundance of the most widely represented PlsEtn species, PE(P-18:0/22:6), which represents a major reservoir of DHA, a fatty acid essential for brain development and function. This study joins others that suggest inulin may have deleterious effects. The consequences of these alterations on the physiology and the functioning of the brain, as well as the molecular mechanisms that link inulin/gut microbiota and Pl levels in the brain, remain to be elucidated.


    • Hi Dave! Thanks for the link.
      Researchers routinely overdose rodents to make sure their study’s treatment has an effect. I stay away from overdosed animal studies because it’s unethical to mistreat animals.
      Researchers violate the basic purpose of animal studies – to help humans – in treating them with doses humans can’t tolerate. Can’t tell you how many sulforaphane studies I’ve read but haven’t curated because of overdosing. At least a half-dozen in the past five days.
      I usually go straight to the Materials and Methods section before I start reading other sections. From this study:
      “Inulin group (INU; n = 11) received a purified diet supplemented with 200 g inulin/kg.” A human equivalent inulin dose is (200 grams x .081) = 16.2 g; (16.2 g x 70 kg human) = 1,134 grams daily.
      If a human eats more inulin than 10 grams a day, they will get intestinal distress and stop.

  2. Dang! Inulin Supplementation Disturbs Hepatic Cholesterol and Bile Acid Metabolism Independent from Housing Temperature 2020 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7589137/
    “Our studies indicate that even relatively short periods of inulin consumption in mice with an intact gut microbiome disturb systemic cholesterol and bile acid metabolism and may have detrimental effects on liver function.”
    I am still pounding broccoli sprouts.

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