High amylose polysaccharide, particularly high-amylose maize starch (HAMS), has been studied for its effects on gut health, including in the context of Irritable Bowel Syndrome (IBS). The scientific rationale is primarily based on its function as a type of resistant starch—a fermentable dietary fiber that resists digestion in the small intestine and is fermented by colonic microbiota. This fermentation produces short-chain fatty acids (SCFAs), such as butyrate, which have been shown to support gut barrier function, modulate inflammation, and influence gut motility.

Several small-scale clinical trials and pilot studies have evaluated the effects of resistant starch supplementation in individuals with IBS. Some studies report improvements in stool consistency, frequency, and overall symptom severity, particularly for constipation-predominant IBS. However, results are mixed, with some participants experiencing increased bloating or discomfort due to gas production from fermentation. A 2021 systematic review (Halmos et al., Alimentary Pharmacology & Therapeutics) concluded that while resistant starches like HAMS may benefit some IBS patients, the overall evidence is moderate and further large, well-controlled trials are needed.

In summary, the use of high amylose polysaccharide for IBS is scientifically motivated and partially supported by experimental evidence, but it is not yet universally recommended due to variability in individual response and limited large-scale data.