Beta-Glucan Overview

The term “beta-glucan” refers to a class of soluble fibers found in many plant sources. The best documented use of beta-glucan involves improving heart health; the evidence for benefit is strong enough that the FDA has allowed a “heart healthy” label claim for food products containing substantial amounts of beta-glucan. ¹ Much weaker evidence supports the potential use of certain beta-glucan products for modifying the activity of the immune system.

Beta-glucan is not an essential nutrient. It is found in whole grains (especially oats, wheat, and barley) and fungi such as baker’s yeast, Coriolus versicolor , and the medicinal mushrooms maitake and reishi .

Different food sources contain differing amounts of the various chemical constituents collectively called beta-glucan. Grains primarily contain beta-1,3-glucan and beta-1,4-glucan. Fungal sources contain a mixture of beta-1,3-glucan and beta-1,6-glucan. Purified products containing only the 1,3 form are also available.

For improving total and LDL cholesterol, studies have found benefit with beta-glucan at doses ranging from 3 to 15 grams daily. However, benefits have been seen more consistently at the higher end of this range, and one carefully designed study found no benefit at 3 grams daily. ² Beta-glucan products can contain molecules of various average lengths (molecular weight). Some manufacturers claim superior benefits with either high or low molecular weight versions. However, one study failed to find any difference between high molecular weight and low molecular weight beta-glucan for normalizing cholesterol and blood sugar levels. ³

1. Food and Drug Administration, HHS. Food labeling: health claims; soluble dietary fiber from certain foods and coronary heart disease. Final rule. Fed Regist. 2003;68:44207-44209.
2. Lovegrove JA, Clohessy A, Milon H, et al. Modest doses of beta-glucan do not reduce concentrations of potentially atherogenic lipoproteins. Am J Clin Nutr. 2000;72:49-55.
3. Frank J, Sundberg B, Kamal-Eldin, A et al. Yeast-leavened oat breads with high or low molecular weight beta-glucan do not differ in their effects on blood concentrations of lipids, insulin, or glucose in humans. J Nutr. 2004;134:1384-1388.