Hordeum vulgare L. as a Functional Food for Diabetes Management: A Review of its Bioactive Compounds and Clinical Evidence.

Diabetes mellitus (DM) is an increasingly serious health problem, with type 2 diabetes accounting for the vast majority of cases. Characterized by hyperglycemia and insulin resistance, DM seriousness lies in the complications resulting from hyperglycemia. Functional food and phytotherapy have become viable dietary approaches to assist in managing this illness. The antidiabetic potential of barley (Hordeum vulgare L.) is assessed in this review, highlighting the bioactive components, underlying mechanisms of action, and data from preclinical and clinical research. Barley's therapeutic potential is primarily attributed to its rich content of β-glucans and a diverse array of phytochemicals, including phenolic acids, flavonoids, and Tocols. These compounds exert their effects through multiple mechanisms: β-glucan slows carbohydrate digestion and glucose absorption, while phenolic compounds inhibit key carbohydrate-digesting enzymes (e.g., α-amylase, α-glucosidase) and reduce oxidative stress. Furthermore, barley consumption has been shown to modulate gut microbiota, enhance insulin sensitivity by upregulating GLUT4 expression, and improve renal and pancreatic health in diabetic models. Preclinical studies using diabetic rat models demonstrate that barley extracts can significantly lower blood glucose, improve lipid profiles, and protect against diabetic nephropathy. Clinical trials further confirm these findings, showing that barley-based foods, such as barley-mixed rice, can effectively reduce postprandial glucose and insulin levels in T2DM patients. The cumulative evidence strongly supports the use of barley as a beneficial dietary intervention for glycemic control and metabolic health.