23/10/2026
Bit of excellent science for you 🩵
Welcome to Science Friday.
Today’s topic is:
𝙁𝙧𝙪𝙘𝙩𝙖𝙣𝙨: 𝙎𝙪𝙜𝙖𝙧, 𝙁𝙞𝙗𝙚𝙧, 𝙂𝙤𝙤𝙙 𝙤𝙧 𝙀𝙫𝙞𝙡?
One thing that has been firmly established is that if you pump more than 5 lbs of inulin fructan into the stomach of a horse, you will induce endotoxemia that ultimately leads to laminitis. This does not happen in the real world setting so let’s move away from this artificial construct into something more logical.
First, a common point of confusion. Are fructans “sugars” or “fiber?” It depends on whether you’re referring to plants or mammals. To a plant, fructans are sugar. Plants break the fructan chain into free fructose molecules to use as energy for growth. Mammals lack this ability and instead, the fructan chain is broken down by bacteria, so in this case, fructans act as prebiotic fiber. Both terms are correct if used in context with their respective physiology.
If we go way, way back to equine evolution, the horse adapted to major changes in grasslands by developing a massive fermentation vat, housing billions of bacteria capable of fermenting fiber to volatile fatty acids (VFA’s). VFAs supply about 60-80% of daily equine energy requirements, sourced from structural fiber, soluble fiber, and oligosaccharides like fructans and those of the raffinose family. This is a steady-state fuel source that does not rely on surges of glucose, ideal for a free-ranging animal.
In other mammalian species, fructans enhance the growth of beneficial bacteria, short-chain fatty acid (SCFA) production and improve calcium and magnesium uptake. Most of the equine research involving fructans has been focused on potential harmful effects, so it is challenging to find work related to potential benefit. There is none related to naturally occurring fructans in forage. Researchers used what is commercially available and that is typically inulin fructan.
Small doses of inulin supplementation have been shown in horses to lower triglycerides and cholesterol (PMID: 33781429), moderately improve insulin sensitivity in obese horses (PMID: 20870952), reduced disruptions in the microbial population after exposure to high starch (PMID: 17940163), promote the growth of anti-inflammatory bacteria in the equine gastrointestinal tract (PMID: 34093482) and modest improvement in glucose and insulin clearance when a prebiotic compound with 46.6% fructan derived from Jerusalem artichoke meal was fed (PMID: 28627061). Current research is aimed at colic prevention, explained in this thorough review paper. (PMID: 41815495)
None of these studies are earthshaking or would radically alter feeding recommendations. They do point out that when fructans, even those not typically consumed by equines, may be beneficial. The fructan overload experiments not only created an unrealistic fear, but also spawned “treatments” and supplements, for example, feeding hops to target lactic-acid producing gut bacteria, or to administer “gut-buffers” to offset the “lactic acidemia” from fructan fermentation, or marketing enzymes (fructanase) to break down fructans before they reach the hindgut (some fructan fermentation takes place in the equine stomach, naturally). Given how many eons horses have wandered the earth in some form, constantly adapting to their environment and food sources, it’s hard to imagine in the last 20 years that a staple of their diet is suddenly a problem that needs buffering. I’m in full agreement with this concluding sentence from Cottone and colleagues (PMID: 41815495), “Proposed mechanisms and therapeutic implications are based primarily on extrapolation from non-equine models and limited equine observational data, highlighting critical knowledge gaps and the need for controlled, hypothesis-driven studies in horses.”
How to access references: Go to PubMED (https://pubmed.ncbi.nlm.nih.gov/) and enter the PMID number in the search box.
Kathleen Gustafson, PhD
President and Research Advisor, ECIR Group Inc.
Text to Give anytime: Text 𝗘𝗖𝗜𝗥 𝗧𝗢 𝟴𝟰𝟰-𝟴𝟰𝟰-𝟲𝟴𝟰𝟰. Thank you!
