Although the new Cheerios beta glucan advertisements on TV may lead you to believe otherwise, the answer is a definite no. Whole yeasts alone are not the optimal source of active beta glucan. The content of available glucan in whole yeast is not high enough, which may result in the impurities acting against the biological effects of glucan molecules. In addition, due to their large size, they are normally not phagocytosed by the gut cells and, therefore insufficient potential glucan can enter the body. For mushrooms, the beta glucans need to be separated from the rest of the raw material. They need to go through a process that will free up their health enhancing properties. But eating lots of mushrooms is already a good start, and Japanese people who eat a lot of them have a lower cancer rate because of their beta-glucan content.