High-Amylose Starch and Human Health: Microbiota Modulation, Metabolic Reprogramming, and Disease Prevention

High-amylose starch (HAS) is composed predominantly of linear α-1,4-linked glucose units and is high in resistant starch content. Its unique physicochemical properties and gut fermentation dynamics confer multiple health benefits. This review summarizes HAS digestion, its interactions with gut microbes, and its systemic effects. HAS intake can reshape the gut microbiota by enriching beneficial taxa such as Bifidobacterium, Faecalibacterium, and Akkermansia, while suppressing harmful bacteria like Escherichia coli and Clostridium difficile. These microbial shifts enhance short-chain fatty acid production, improve gut barrier integrity, and reduce inflammation. HAS also demonstrates therapeutic potential in obesity, type 2 diabetes, chronic kidney disease, and colorectal cancer by improving insulin sensitivity, reducing glycemic variability, and modulating oncogenic pathways. Collectively, dietary incorporation of HAS represents a promising functional strategy to support gut and systemic health across diverse physiological contexts.