β-glucans and cholesterol (Review)

Abstract

Hypercholesterolemia is one of primary risk factors of cardiovascular disease, together with metabolic syndrome, hypertension and diabetes. Although progress has been made, the search for novel methods of preventing and treating dyslipidemia is ongoing and current therapies for cardiovascular disease induce various side effects. β‑glucans are linear unbranched polysaccharides found in various natural sources, such as mushrooms. Due to their structure they are able to interact with innate immunity receptors, however they also act as dietary fibers in the digestive tract. As there are two forms of β‑glucans, insoluble and soluble forms, they are able to interact with lipids and biliary salts in the bowel and consequently reduce cholesterol levels. Therefore, they may be developed as a suitable therapeutic option to treat patients with dyslipidemia, as they are natural molecules that do not induce any significant side effects. The current review discusses the evidence supporting the effects of β‑glucans on cholesterol levels.

Figure 1

Schematic representation of the basic molecular structure of glucan molecule. N and N* represent the number of specific repetitions of each structure.

Figure 2

Simplified representation of the effects of β-glucan on immunity and cholesterol balance. (A) β-glucans interact with receptors expressed on the surface of innate immune cells and with iC3b/CR3 complement complex of opsonized cells, resulting in immune stimulation that involves innate and adaptive immunity. (B) It is hypothesized that, acting as fibers, β-glucans can form a gel on the mucosal surface of the bowel. This inhibits resorption of the biliary salts, stimulating biliary salt neo-synthesis in the liver. Increased biliary salts activate utilization of circulating cholesterol, thus reducing its levels in the blood. NK, natural killer cells; CR3, complement receptor type.