Mannan-oligosaccharides and ß-glucans

Highly purified components from the cell walls of true brewer’s yeast are called mannan-oligosaccharides (also known as MOS) and ß-glucans. They contain surface receptors with a high binding capacity for mycotoxins (toxic substances) and pathogenic germs. In addition, the brewer’s yeast cell walls form an additional protective barrier in the gut, a kind of “biofilm”, which prevents bacteria from adhering to the gut mucosa. Trials have shown that MOS can increase anti-inflammatory messenger substances (e.g. IL-10) and antibacterially active enzymes (e.g. lysozyme) of the immune system. Levels of antibodies may also increase.

Furthermore, MOS support the reduction of harmful processes in the gut by inhibiting messenger substances and exerting a positive influence on gut barrier integrity. Finally, the brewer’s yeast cell walls also serve as food for beneficial gut microbes and are therefore prebiotic. Gut cells benefit from higher levels of butyrate, which serves as an energy source for them and contributes to their vitality.

Overall, mannan-oligosaccharides and ß-glucans therefore help relieve the immune system and gut and, through their immunomodulatory properties, can support the immune system in its work. The positive effects of MOS and ß-glucans have been investigated in numerous studies (e.g. Ghyselinck, 2025, Rychlik et al., 2013). They are used in both animal and human health as a nutraceutical and as a multi-prebiotic.