- Beta-glucan is a naturally occurring polysaccharide made up of glucose molecules linked primarily by β-glycosidic bonds.
- Found in the cell walls of cereals (especially oats and barley), fungi (like mushrooms), yeasts, seaweed, and some bacteria, beta-glucans vary in their structure and solubility depending on the source, which in turn influences their biological activity and health benefits. These variations are mainly due to the type and frequency of β-(1→3), β-(1→4), and β-(1→6) linkages, which determine the polymer’s branching, solubility, and ability to interact with biological receptors.
- One of the most well-studied forms of beta-glucan is the soluble beta-glucan found in oats and barley, which is recognized for its cholesterol-lowering and blood sugar-modulating properties. These effects stem from its ability to form a viscous gel in the digestive tract, which slows gastric emptying, reduces the absorption of dietary cholesterol, and moderates postprandial glucose spikes. As a result, consuming beta-glucans from oats or barley has been linked to reduced levels of low-density lipoprotein (LDL) cholesterol, a lowered risk of cardiovascular disease, and improved glycemic control, especially in individuals with type 2 diabetes or metabolic syndrome. For these reasons, health authorities such as the U.S. FDA and the European Food Safety Authority (EFSA) have approved health claims for oat and barley beta-glucans.
- Beta-glucans derived from yeast and fungi—such as those from Saccharomyces cerevisiae or Lentinula edodes (shiitake mushrooms)—are structurally different and are known primarily for their immunomodulatory effects. These beta-glucans typically contain β-(1→3) backbones with β-(1→6) branching, which allow them to bind to specific immune cell receptors, such as Dectin-1 and CR3. Upon binding, beta-glucans can enhance the activity of macrophages, neutrophils, and natural killer (NK) cells, thereby boosting innate immune responses and supporting host defense against infections and, potentially, tumors. They are increasingly being studied as adjuvants in cancer immunotherapy, vaccine enhancement, and in formulations aimed at reducing susceptibility to upper respiratory tract infections.
- From a nutritional standpoint, beta-glucan is also considered a soluble dietary fiber and contributes to gut health by acting as a prebiotic, promoting the growth of beneficial microbiota such as Bifidobacterium and Lactobacillus. This microbial modulation is believed to play a role in systemic effects, including anti-inflammatory actions, improved gut barrier integrity, and potentially even mood and cognitive health via the gut–brain axis.
- In the food industry, beta-glucan is utilized not only for its health benefits but also for its functional properties. Its ability to increase viscosity and form gels makes it useful as a fat replacer, stabilizer, or texturizer in low-fat and gluten-free products. In the pharmaceutical and nutraceutical sectors, purified beta-glucans are being incorporated into dietary supplements, topical applications, and functional foods targeting immunity, cholesterol reduction, or digestive health.
