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INTRODUCTION: |
| Yeast beta-D-glucan is marketed as a nutritional supplement. The yeast beta-D- |
| glucan in the supplement is a polyglucose polysaccharide derived from the cell |
| walls of baker's yeast or Saccharomyces cerevisiae. Yeast beta-D-glucan, usually |
| referred to as yeast beta-glucan, consists of straight-chain and branched |
| polymers. The straight-chain structures are (1/3)-beta-D-linked glucose polymers |
| and (1/6)-beta-D-linked glucose polymers. Yeast beta-glucan appears to have |
| immunomodulatory properties. It is being evaluated in clinical studies as an |
immunomodulatory agent and a biological response modifier. |
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ACTIONS: |
Yeast beta-glucan may have immunomodulatory and lipid-lowering activity. |
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MECHANISM ACTIONS: |
| Yeast beta-glucan can bind to a beta-glucan receptor in macrophages and stimulate |
| the production of such cytokines as TNF (tumor necrosis factor)-alpha and IL |
| (interleukin)-I beta. Binding to the beta-glucan receptor may also induce the release |
| such reactive oxygen species as superoxide anions and hydrogen peroxide. Yeast |
| of beta-glucan may also stimulate such cells as neutrophils NK (natural killer cells) |
| and LAK (lymphokine-activated killer) cells. All of the above stimulation effects may |
| result in antimicrobial and tumoricidal activities.yeast beta-glucan may be |
considered an immune system primer. |
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| Yeast beta-glucan is an indigestible polysaccharide and very little hydrolysis of it |
| takes place in the stomach or small intestine. There is some digestion of yeast |
| beta-glucan that does take place in the large intestine via bacterial beta- |
| glucosidases, and some remnants of this digestion, oligosaccharides with |
| molecular weights of up to 20,000 daltons, have been detected in the serum of |
| animals, as well as of humans, Yeast beta-glucan has been found to lower total |
cholesterol levels as well as to increase levels of HDL-cholesterol. Yeast beta-glucan may also promote the excretion of bile acids. |
