Beta glucans are complex sugars, known as polysaccharides, found in various natural sources. Research explores their potential in supporting overall health, particularly their influence on immune responses. This article examines beta glucans’ origins, how they interact with the immune system, and current scientific findings related to their role in cancer research, including considerations for use and safety.
Understanding Beta Glucans
Beta glucans are a group of polysaccharides, large molecules made up of D-glucose units. They are widely distributed in nature, forming components of cell walls in various organisms. Common dietary sources include cereals like oats and barley, as well as the cell walls of fungi, yeast (such as baker’s yeast), and certain mushrooms like reishi and shiitake.
The specific chemical structure of beta glucans, including their molecular mass, branching patterns, and glycosidic bonds, varies depending on their source. For instance, yeast and fungal beta glucans typically feature a 1,3-glucose backbone with 1,6-glucose branches, while cereal beta glucans contain both 1,3 and 1,4 backbone bonds. These structural differences influence their solubility and biological activity within the body.
How Beta Glucans Influence Immunity
Beta glucans modulate the immune system, acting as biological response modifiers. They interact with specific receptors on various immune cells, such as macrophages, neutrophils, dendritic cells, and natural killer (NK) cells. These receptors, known as pattern recognition receptors (PRRs), include Dectin-1 and Complement Receptor 3 (CR3).
When beta glucans bind to these receptors, they initiate signaling events within the immune cells. This activation enhances the cells’ ability to recognize and engulf foreign particles or abnormal cells, a process called phagocytosis. Activated immune cells then release signaling molecules, such as cytokines like interleukin-12 (IL-12) and interleukin-6 (IL-6), which further amplify immune responses. This heightened immune surveillance can help the body identify and target abnormal cells, including those associated with tumors.
Scientific Findings in Cancer Research
Research into beta glucans’ role in cancer has shown promising results in various study settings. In laboratory in vitro (cell culture) and in vivo (animal) studies, beta glucans have demonstrated a capacity to inhibit the growth of cancer cells, induce programmed cell death (apoptosis), and hinder the formation of new blood vessels that tumors need to grow (angiogenesis). They have also been observed to slow tumor progression and reduce the spread of cancer cells (metastasis).
Limited but growing human clinical trials have explored beta glucans, often as an adjunctive therapy alongside conventional cancer treatments such as chemotherapy and radiotherapy. Some studies suggest that when used with standard treatments, beta glucans may improve patient quality of life by mitigating adverse reactions like nausea, abdominal pain, fatigue, and leukopenia. For example, studies involving hepatocellular carcinoma, gastric cancer, and colorectal cancer have indicated that beta glucans may improve five-year survival rates and reduce recurrence rates.
Considerations for Use and Safety
Beta glucans are generally considered safe when consumed orally in amounts typically found in foods or as supplements for short periods. Mild side effects may include digestive issues like diarrhea, nausea, or fatigue. However, intravenous administration of certain beta glucan solutions has been associated with more serious side effects, including spleen problems and blood clots.
Individuals considering beta glucan supplements, particularly those undergoing cancer treatment, should consult a healthcare professional before starting. Interactions are possible with certain medications, such as immunosuppressants and some blood pressure medications. Beta glucans might decrease the effectiveness of immunosuppressants by increasing immune system activity, and could lead to excessively low blood pressure when taken with antihypertensive drugs. Pregnant and breastfeeding individuals are advised to avoid beta glucan supplements due to insufficient safety research.