Natural beta-glucan is a dietary supplement found in several common foods, including oats, barley, mushrooms and yeast. Beta-glucan appears in different molecular linkages (1-3, 1-4 and 1-6) depending on the source, with 1-3/1-4 being water-soluble and 1-3/1-6 being insoluble. Beta-glucan possesses several beneficial qualities, including the ability to fight off free radicals in a similar way to antioxidants. Studies suggest that beta-glucan in oats and barley lowers LDL (negative) cholesterol while leaving HDL (positive) cholesterol unaffected. As a result of these studies, the FDA approved the usage of claims regarding the benefits of soluble fibre on health for foods made with oats. The reduction in cholesterol from barley beta-glucan benefits diabetics, in particular, while supporting general immune system health. Beta-glucan in shitake mushrooms and yeast helps ward off illness through several mechanisms, including by helping macrophage cells destroy pathogens that attack the body and cause infection.
Oats possess high amounts of beta-glucan in the form of soluble fibre, which helps lower cholesterol. There are two types of fibre in the diet: soluble and insoluble. Soluble fibre slows down the release of sugars into the bloodstream and extends the feeling of satiety after eating, while insoluble fibre promotes the regulation of the gastrointestinal tract. Oat-derived beta-glucan is linked to lower blood sugar and insulin levels in people with diabetes. Studies show that cooking oats for an extended period of time diminishes the positive qualities associated with beta-glucan.
Barley also boasts large amounts of beta-glucan, which acts similarly to that in oats (although barley has less fat than oats). Barley beta-glucan works by converting into a water-soluble gel, which facilitates the absorption of nutrients in the intestines while slowing digestion and trapping fats and carbohydrates. The feeling of fullness that results from slower digestion promotes diet control and weight loss by curbing hunger.
Mushroom and Yeast
Mushroom and yeast beta-glucan has the effect of aiding in the body's natural immune defences by acting as an immunomodulator. Two of the most common sources of these types of beta-glucan are shitake mushrooms and Baker's yeast, both of which can be found in many grocery stores. In experiments, cells in mice fed shitake-derived beta-glucan blocked the progression of cancer cells, and in other studies, beta-glucan activated cytokines, which fight off infection naturally in the body. Yeast-derived beta-glucan acts similarly to support the immune system, while both mushroom and yeast beta-glucan molecules behave differently from those in oats and barley, which serve primarily in digestion.