The importance of dietary fiber as part of a balanced diet for human health is widely recognized. The β-glucans are a type of soluble fiber for which effects on glycemia, insulinemia levels, cholesterol, and immunity have been proposed.
Beta glucans are long chains of glucose molecules that form a non-digestible fiber. Beta glucan is found in various organisms, including cereal grains like oat and barley, fungi, bacteria, and algae.
Different sources of beta-glucan
Beta glucans exist in a variety of structures and serve different purposes depending on the source. Those different structures impact how the beta glucans interact with their bodies and when we consume them, and what health benefits are associated with them, but not all beta glucans are the same. These different sources of beta glucans can have different health benefits based on their function, structure, size, and solubility.
In this article, we will discuss the different sources of beta glucan and their functions.
1. Beta-glucans from cereals (oat, barley)
The structure of Beta-glucans from cereals
It is a viscous polysaccharide made up of units of the monosaccharide D-glucose. Oat beta glucan is composed of mixed-linkage polysaccharides. This means the bonds between the D-glucose units are either beta-(1,3) linkages or beta-(1,4) linkages.
The function of Beta-glucans from cereals
See that cellulose found in plants is a 1,4 structure and is associated with gut motility. Oat and barley have beta glucan that has mostly 1,4 linkages but also has some alternating 1,3 linkages. This structure is associated with cardiovascular health benefits. Those benefits are often advertised on the boxes of whole-grain cereals, the big heart.
The effects are proposed to be mediated by the gel-forming properties of oat β-glucan, which modulates host bile acid and cholesterol metabolism and potentially removes intestinal cholesterol for excretion. However, the gut microbiota has emerged as a major factor regulating cholesterol metabolism in the host.
2. Beta-glucans from yeast and fungi(mushroom)
The structure of beta-glucans from yeast and fungi
The β-glucan present in yeast and fungi was composed of (1,3) linkages and (1, 6) linked branches. The difference between them is that β-glucans of mushrooms have short β(1,6)-linked branches whereas those of yeast have β(1,6)-side branches with additional β(1,3) regions. Yeast beta-glucan is a long chain of polysaccharides.
The function of beta-glucans from yeast and fungi
Yeast beta-glucan exists in the cell wall of yeast and is well-known for the functions of immunity-enhancing, anti-infection, anti-tumor, and so on.
Beta-1,3/1,6-glucan derived from baker’s yeast (Saccharomyces cerevisiae) is the most studied beta-glucan and is by far the best documented in terms of immune stimulatory efficacy and safety is hence considered superior to beta-glucans from other sources.
3. Beta-glucans from bacteria and algae
The structure of beta-glucans from bacteria and algae
β-Glucan obtained from bacteria and algae show as a linear β-(1,3) glucan structure.
The function of beta-glucans from bacteria and algae
The main function of this 1,3-bonded glucan is to promote intestinal health and some of the beta glucan from algae have a function to enhance immunity.
Foods high in beta glucan
There are also many foods high in beta glucan, including barley fiber, oats, whole grains, reishi, maitake and shiitake mushrooms, seaweed, algae.
The best way to intake the beta glucan
Many food manufacturers add beta glucan to functional drinks and foods as a supplement. The best way to consume glucan is to eat foods containing high-purity beta glucan.
Before buying that kind of product, it’s necessary to learn different beta glucan sources and their functions.