Beta-glucan's therapeutic uses
Beta-glucan is a naturally occurring soluble fiber found in various plant sources, including whole grains like oats and barley, as well as certain fungi such as shiitake and medicinal mushrooms. Its primary therapeutic use is in improving heart health by modestly lowering total and LDL (bad) cholesterol levels, with effective doses typically ranging from 3 to 15 grams per day. Additionally, beta-glucan may have benefits for blood sugar control and could help mitigate post-meal spikes, making it potentially beneficial for individuals with diabetes.
Beyond cardiovascular health, beta-glucan is proposed to have immunomodulatory properties, influencing various aspects of immune function, although the evidence is still emerging and not fully conclusive. This has led to its exploration in the treatment of diverse conditions, including allergic rhinitis, cancer, and infections. Furthermore, beta-glucan may support wound healing when applied topically and act as a prebiotic to promote gut health, though clinical evidence for these uses is still preliminary. Generally regarded as safe, beta-glucan should be approached cautiously by individuals with certain autoimmune conditions or those on immunosuppressive medications. Overall, while beta-glucan presents several promising therapeutic uses, further research is needed to fully confirm these benefits and establish guidelines for use.
Beta-glucan's therapeutic uses
DEFINITION: Natural plant product used to treat specific health conditions.
PRINCIPAL PROPOSED USE: High cholesterol
OTHER PROPOSED USE: Immune support, blood sugar control, wound healing, gut health
Overview
The term “beta-glucan” refers to a class of soluble fibers found in many plant sources. The best-documented use of beta-glucan involves improving heart health; the evidence for benefit is strong enough that the US Food and Drug Administration (FDA) has allowed a “heart healthy” label claim for food products containing substantial amounts of beta-glucan. Much weaker evidence supports the potential use of certain beta-glucan products for modifying the activity of the immune system.
Requirements and Sources
Beta-glucan is not an essential nutrient. It is found in whole grains (especially oats, wheat, and barley) and fungi such as baker’s yeast, Coriolus versicolor, and the medicinal mushrooms maitake and reishi.
Different food sources contain differing amounts of the various chemical constituents collectively called beta-glucan. Grains primarily contain beta-1,3-glucan and beta-1,4-glucan. Fungal sources contain a mixture of beta-1,3-glucan; purified products containing only the 1,3 form are also available.
Therapeutic Dosages
For improving total and LDL (low-density lipoprotein) cholesterol, studies have found benefit with beta-glucan at doses ranging from 3 to 15 grams (g) daily. However, benefits have been seen more consistently at the higher end of this range, and one carefully designed study found no benefit at 3 grams daily.
Beta-glucan products can contain molecules of various average lengths (molecular weight). Some manufacturers claim superior benefits with either high- or low-molecular-weight versions. However, one study failed to find any difference between high-molecular-weight and low-molecular-weight beta-glucan for normalizing cholesterol and blood sugar levels.
Therapeutic Uses
A substantial, if not entirely consistent, body of evidence indicates that beta-glucan, or foods containing it (especially oats), can modestly improve a person’s cholesterol profile. The most reliable benefits have been seen regarding levels of total cholesterol and LDL (low-density lipoprotein, or bad) cholesterol. Modest improvements of up to 10 percent have been seen in studies. Possible improvements in HDL (high-density lipoprotein, or good) cholesterol have been seen only inconsistently. It is thought that beta-glucan reduces cholesterol levels by increasing the excretion of cholesterol from the digestive tract. This affects two forms of cholesterol: cholesterol from food and, more importantly, cholesterol from the blood “recycled” by the liver through the intestines. However, virtually all studies involved oats and were conducted by manufacturers of oat products; independent confirmation remains minimal.
Beta-glucan may also modestly improve blood pressure levels, though not all studies agree. In addition, beta-glucan may help limit the rise in blood sugar that occurs after a meal. This could, in theory, offer heart-healthy benefits, especially in people with diabetes.
Another primary proposed use of beta-glucan products involves effects on the immune system. Test tube, animal, and a few controlled studies in humans suggest that beta-glucans can alter various measurements of immune function. In the alternative medicine literature, these effects are commonly summarized as indicating that beta-glucan is an “immune stimulant.” This description, however, is an oversimplification. The immune system is extraordinarily complicated and not yet completely understood. It is impossible to characterize the effects of beta-glucan more precisely than to say that it has “immunomodulatory” actions or is a “biological response modifier.” These intentionally unsensational terms indicate that it is known that beta-glucan affects (modulates) immune function, not that it improves immune function. Some of the immune-related effects seen in studies include alterations in the activity of certain white blood cells and changes in the levels or actions of substances, called cytokines, that modulate immune function.
Based on these largely theoretical findings and some human trials, various beta-glucan products have been advocated for the treatment of conditions as diverse as allergic rhinitis, cancer, infections, and sepsis (overwhelming infection following major trauma, illness, or surgery). Beta-glucans are also posited as effective in promoting wound healing when applied topically by stimulating collagen production. Beta-glucans can also act as a prebiotic and promote a healthy gut biome. However, the evidence for actual clinical benefit remains highly preliminary.
One study failed to find that beta-1,3-glucan (in topical gel form) was helpful for treating actinic keratosis, a form of sun-induced precancerous changes seen in aging skin. Another found that it had no significant effect on periodontal disease (gingivitis), an inflammation of the gums caused by bacteria found in dental plaques.
Other studies found beta-glucan to positively impact colon health and possibly decrease the chances of colon cancer. Its prebiotic properties lower inflammation and aid in the proper functioning of the gastrointestinal tract.
Safety Issues
Beta-glucan, as a substance widely present in foods, is thought to have a high margin of safety. However, if it does activate the immune system, harmful effects are at least theoretically possible in people with conditions in which the immune system is overactive. These include multiple sclerosis, lupus, rheumatoid arthritis, asthma, inflammatory bowel disease, and hundreds of other conditions, many of which are autoimmune conditions. In addition, people taking immunosuppressant drugs following organ transplantation surgery could, in theory, increase their risk of organ rejection. However, there are no reports yet to indicate that any of these hypothetical problems have occurred. Maximum safe doses in young children, pregnant or nursing women, or people with severe liver or kidney disease have not been established.
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