Oat Beta Glucan
Beta glucan is a cluster of soluble fiber derived from multiple organic sources, including mushrooms, yeast, oats and barley.
Beta glucan is not a single molecule but is a type of polysaccharide that exists in different sizes and different degrees of solubility and ability to be absorbed into the bloodstream. One can find Beta glucan that is big (of high molecular weight) or small (of low molecular weight). There are several different linkages between the different saccharide molecules that make up Beta glucan.
Molecular linkages can be of a (1,4) type, a (1,3) type and a (1,6) linkage. These are important because each linkage type creates a different molecular shape for the Beta glucan and may account for their function inside the body.
When looking at research done on this nutritional molecule, you'll see that the effects one gets from one source of Beta glucan may not be the same effects you'll find from another source of Beta glucan.
When looking at Beta glucan derived from oats, the research has focused almost exclusively on only two positive effects of this type of Beta glucan. Those two effects are that on cholesterol and blood sugar challenged individuals. More than one study has shown that feeding an individual or animal dietary Beta glucan from an oat source will lower the cholesterol by 9%. Other studies confirmed that only certain types of people will respond to dietary oat fiber and still others show that cooking the oat-derived Beta glucan markedly decreased the effectiveness of the soluble fiber. Cooking the oats may destroy some of the linkage bonds in the molecule.
Research on blood sugar challenged individuals showed lower insulin and blood sugar levels when a person ate oat-derived Beta glucan as compared to control subjects. The mechanism of action of this product against high blood sugar is unknown.
In addition, oat-derived Beta glucan seems to increase the amount of bile acids secreted in human test subjects. Bile acids come from the liver and gall bladder and contain a significant amount of cholesterol.
Unlike mushroom and yeast Beta glucan, there were no studies looking at oat Beta glucan helping things like the immune system or tumor-fighting abilities. Non-oat sources of Beta glucan have numerous articles which speak of these aspects of Beta glucan. In fact, the function of oat-derived Beta glucan could all be explained by Beta glucan acting inside the digestive tract—binding sugar and cholesterol, for example. It's conceivable that this is because oat-derived Beta glucan is too big to be absorbed or is of a molecular structure that doesn't allow for absorption into the body.
The known systemic effects of Beta glucan, like anti-tumor or inflammatory effects, just don't happen with oat-derived Beta glucan. The research showing the effectiveness of oat-derived Beta glucan on the immune system or against tumors isn't out there. Taking oat-derived Beta glucan for cholesterol reduction and to control blood sugar are the only fully-researched reasons for taking it.
While both oat beta glucan has been approved for the claim that can reduce cholesterol there is no peer-reviewed studies that have shown the beneficial effects of immune system support.
Bakers yeast derived Beta glucan has shown positive results on cholesterol and blood sugar challenged individuals as well as it has proven to be a powerful, safe and effective immune system support material that has been shown to provide a broad range of benefits not limited to the oat beta glucan benefits. Bakers yeast derived Beta glucan is not a treatment for any disease or condition. It is an immunomodulator that has been shown to support immune system function.
While oat beta glucan has been shown to provide heart health related benefits, yeast-derived Beta glucan has shown similar positive results. Results include cholesterol and blood sugar challenged individuals. Yeast-derived Beta glucan has also proven to be a powerful immune system support material.
 Chang YJ, et al. “Structural and biological characterization of sulfated-derivatized oat beta-glucan.” J Agric Food Chem . 2006 May 31;54(11):3815-8.
 Uusitopa, MI, et al. “A controlled study on the effect of beta-glucan-rich oat bran on serum lipids in hypercholesterolemic subjects: relation to apoliproprotein E phenotype.” J Am Coll Nutr . 1992 Dec;11(6):651-9.
 Lia A, et al. “Oat beta-glucan increases bile acid excretion and a fiber rich barley fraction increases cholesterol excretion in ileostomy subjects.” Am J Clin Nutr . 1995 Dec;62(6):1245-51.
 Pick ME, et al. “Oat bran concentrate bread products improve long-term control of diabetes: A pilot study.” J Am Diet Assoc . 1996 Dec;96(12):1254-61.
 Braaten JT, et al. “Oat beta-glucan reduces blood cholesterol concentration in hypercholesterolemic subjects.” Eur J Clin Nutr . 1994 Jul;48(7):465-74.
 Kerckhoffs DA, et al. “Cholesterol-lowering effect of beta-glucan from oat bran in mildly hypercholesterolemic subjects may decrease when beta-glucan is incorporated into bread and cookies.” Am J Clin Nutr . 2003 Aug;78(2):221-7.
 Aman P, et al. “Starch and dietary fiber components are excreted and degraded to variable extents in iliostomy subjects consuming mixed diets with wheat- or oat-bran bread.” J Nutr . 1995 Sep;125(9):2341-7.