Beta-glucans are a class of natural polysaccharides (polymers of sugars) that are naturally presented in the cell walls of certain plants including mushrooms, and also micro-organisms such as yeast and other fungi and certain bacteria. Certain polysaccharides with specific structures such as beta-D-(1,3/1,6)-glucan, are the active ingredients in many well-known immuno-modulatory foods and herbs including Baker’s yeast, Reishi, Shitake and pine mushroom, Astragalus root and ginseng. Due to these polysaccharides are similarly found in microorganisms, our immune cells regard them as “pathogen-associated molecules” and will elicit an activated immune response to prepare our body for defense. Other beta-glucan, such as oat beta-glucan, without such specific structure [(1,3/1,6)-glucan] does not have the immune stimulatory effect.
Yeast beta-glucan has been shown in clinical studies with immune-enhancing efficacy in humans including:
1. enhanced the immune cells (CD14+ monocytes; Natural Killer cells)
2. boosted the potential production of immune cytokines (IL-2,4,5 and IFNg) post-exercise
3. increase immunoglobulin (IgA) in saliva
4. reduced the symptoms of upper respiratory tract infection
Auinger, A., L. Riede, et al. (2013). “Yeast (1,3)-(1,6)-beta-glucan helps to maintain the body’s defence against pathogens: a double-blind, randomized, placebo-controlled, multicentric study in healthy subjects.” Eur J Nutr 52(8): 1913-1918.
Bergendiova, K., E. Tibenska, et al. (2011). “Pleuran (beta-glucan from Pleurotus ostreatus) supplementation, cellular immune response and respiratory tract infections in athletes.” Eur J Appl Physiol 111(9): 2033-2040.
Carpenter, K. C., W. L. Breslin, et al. (2013). “Baker’s yeast beta-glucan supplementation increases monocytes and cytokines post-exercise: implications for infection risk?” Br J Nutr 109(3): 478-486.
Fuller, R., H. Butt, et al. (2012). “Influence of yeast-derived 1,3/1,6 glucopolysaccharide on circulating cytokines and chemokines with respect to upper respiratory tract infections.” Nutrition 28(6): 665-669.
Lehne, G., B. Haneberg, et al. (2006). “Oral administration of a new soluble branched beta-1,3-D-glucan is well tolerated and can lead to increased salivary concentrations of immunoglobulin A in healthy volunteers.” Clin Exp Immunol 143(1): 65-69.
McFarlin, B. K., K. C. Carpenter, et al. (2013). “Baker’s yeast beta glucan supplementation increases salivary IgA and decreases cold/flu symptomatic days after intense exercise.” J Diet Suppl 10(3): 171-183.