Beta glucans are naturally occurring polysaccharides that are found in the cell walls of algae, bacteria, lichens, and yeasts. These sugars can also be found in plants, such as barley and oats. They are used in the manufacturing of food additives, as well as in medicines that help lower cholesterol levels and boost the immune system.
The most common use in manufacturing is in food additives or food ingredients in cheese spreads, frozen desserts, salad dressings, and sour cream. Yeast extract and baker's yeast are forms that appear frequently on food labels. Other forms may be used to improve the properties of food emulsions or in soluble fiber supplements.
Concentrated yeast beta glucans are more easily incorporated into food products than are grain-derived forms. Yeast forms are used more in medicine as well, although oat beta glucan is thought to have more therapeutic potential. Enriched barley glucan did not prove effective in some tests, although more research is being conducted on processing methods for enriched products. Forms of beta glucans derived from shiitake mushrooms and other fungi have shown effectiveness in certain medical uses and are being studied.
Beta glucan benefits may include lower cholesterol levels and immune system improvements. When yeast beta glucan is taken by mouth, it is thought to help prevent the absorption of cholesterol during digestion in both the stomach and intestines. German research presented at the First International Congress on Pre-Diabetes and Metabolic Syndrome found that barley beta glucan reduces serum lipid levels, as well as cholesterol, triglycerides, and glycemic control markers.
Many experts agree that early evidence from human trials on the use of beta glucans to help control blood sugar is promising, but suggest more research is necessary. There is, however, strong support for their use in boosting the immune system in people with acquired immune deficiency syndrome (AIDS) or human immunodeficiency virus (HIV) infections. Injections of beta glucans also may be given after surgery to help prevent infection. Beta glucan supplements are sold over the counter as supplements to people who believe the sugars are useful in treating other conditions that benefit from a boost to the immune system.
Studies indicate an increased survival rate in some cancer patients when given beta glucans intravenously or by injection along with conventional treatment. The beta glucan treatments typically must be given for at least a year to be effective. Specific kinds of beta glucans may be given intravenously to extend the life of some people with certain advanced cancers.
Although beta glucans in foods are generally recognized as safe, there can be side effects to medicinal formulations. Fungal and yeast versions appear to be well tolerated when taken by mouth. Intravenous treatments can cause numerous side effects, including dizziness, headaches, nausea, and blood pressure changes.