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Beta-glucan |
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Beta-glucan is a soluble fiber that is derived from the cell walls of plants, algae, fungi, yeast and bacteria. Several studies have shown that beta-glucan changes the way the body’s immune system reacts by encouraging white blood cells to remain in a constant state of preparedness. This preparedness enhances the overall performance of the immune system and allows it to immediately attack invading organism before they cause any serious damage.
The use of beta-glucan for health purposes is relatively new. Beta-glucan is often used for its cholesterol-lowering effects, its ability to control blood sugar, and as a supplemental cancer treatment. The Food and Drug Administration first recognized the health benefits of beta-glucan in 1997 when it passed a ruling allowing oat bran to be registered as a cholesterol-lowering food. The FDA recommended a daily dosage of 3 grams of beta-glucan for cholesterol-lowering effects.
Beta-glucan primarily performs the function of coating the digestive system. Unlike proteins, sugars and starches, beta-glucan is not digested by intestinal enzymes but transforms into a non-digestible, water-soluble gel that coats the intestine. Dietary fat and carbohydrates get trapped by this gel, which has the effect of regulating the rate at which nutrients are absorbed and digested. This water soluble gel also traps cholesterol and fats and flushes them out of the body.
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Beta-glucan was discovered during clinical studies of the drug Zymosan, commonly used throughout Europe in the 1940s. Researchers were excited to discover that Zymosan enhanced immune system function irrespective of the type of pathogen invading the body. In the 1960s, Nicholas DiLuzio Ph.D. first identified the active ingredient in Zymosan as the long-chained polysaccharide, Beta-1, 3-D-glucan. Studies continued into the benefits of beta-glucan, and in the mid-1970s, Dr. Peter W. Mansell introduced beta-glucan as a possible treatment for cancer. Dr. Mansell reported that beta-glucan injected into malignant skin cancer nodules in 9 patients led to a reduction in size of the legions within as short a period as 5 days.
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Evidence points to the possibility that the anti-viral qualities of beta-glucan may be enhanced with vitamins A, C and E, alpha lipoic acid, selenium and/or quercetin.
Hunter K, Gault R, Jordan F. Mode of Action of B-Glucan Immunopotentiators. University of Nevada School of Medicine, Dept of Microbiology, Research Summary Release. 2001 Jan.
Meira, et al. The Use of Glucan as Immunostimulant in the Treatment of Paracoccidioidomycosis. Am J Trop Med Hyg. 1996;55(5):496-503.
Novak M, Vetvicka V. Beta-Glucans, History, and the Present: Immunomodulatory Aspects and Mechanisms of Action. Immunotoxicol. 2008 Jan;5(1).
Cholesterol Levels & Heart Disease
There are 3 primary mechanisms by which Beta-glucan helps lower cholesterol levels and reduces the risk of heart disease:
Reduced Cholesterol Absorption - Beta-glucan suppresses or decreases the uptake of dietary cholesterol either by retaining cholesterol in the gel-like viscous medium or by obstructing micelle formation, which means it prevents the formation of lipoproteins that are necessary for the transportation of lipids.
Reduced Bile Acid Absorption - Like other soluble fibers, Beta-glucan reduces the hepatic cholesterol pool. Micelles formed from bile acids are necessary for the absorption of cholesterol. These bile acids are synthesized from cholesterol by the liver and they then released into the small intestine. Obstruction in the re-absorption of these bile acids necessitates further synthesis, thus drastically reducing existing cholesterol stores.
Reduced Cholesterol Synthesis - All soluble fibers including Beta-glucan interfere with the cholesterol biosynthesis in the liver by inhibiting the activity of a key enzyme, 3-hydroxy,3-methylglutaryl coenzyme A (HMG CoA) reductase.
Various research into the effects of Beta-glucan on cholesterol levels has led the FDA to publish a report stating that barley foods supplying 3 grams of beta-glucan per day could potentially reduce cholesterol by 5. In addition to cholesterol-lowering, Beta-glucan also favorably influences many heart disease risk factors alterable by diet including: the management and prevention of type-2 diabetes, the enhancement of weight loss, and the reduction of blood pressure.
Braaten JT, Wood PJ, Scott FW, et al. Oat beta-glucan reduces blood cholesterol concentration in hypercholesterolemic subjects. Eur J Clin Nutr. 1994;48:465-74.
Davidson MH, Dugan LD, Burns JH, et al. The hypocholesterolemic effects of beta-glucan in oatmeal and oat bran. A dose-controlled study. JAMA. 1991;265:1833-9.
Lia A, Hallmans G, Sandberg AS, 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;62:1245-51.
Queenan KM, Stweart ML, Smith KN, et al. Concentrated oat beta-glucan, a fermentable fiber, lowers serum cholesterol in hypercholesterolemic adults in a randomized, controlled trial. Nutr J. 26 March 2007;6(6):1475-2891.
Hypoglycemia
Essentially, Beta-glucan helps lower the Glycemic Index by slowing down the absorption of glucose.
Although there are several human trials that fundamentally support the use of Beta-glucan for glycemic (blood sugar) control and early evidence looks promising, additional research and study is still necessary before a firm recommendation can be made.
Diabetic individuals have to exercise special precaution before they can take Beta-glucan. This is because, even though Beta-glucan comes under the GRAS (Generally Regarded as Safe) category in the United States, all dietary supplements that are capable of altering blood sugar levels may also create serious adverse side effects in diabetic individuals.
Behall KM, Scholfield DJ, Hallfrisch JG. Barley beta-glucan reduces plasma glucose and insulin responses compared with resistant start in men. Nutr Res. (26):644-650.
Braaten JT, Scott FW, Wood PJ, et al. High beta-glucan oat bran and oat gum reduce postprandial blood glucose and insulin in subjects with and without type 2 diabetes. Diabet Med. 1994;11:312-8.
Crohn’s Disease
While it has been proposed that Beta-glucan may be beneficial for treating patients with Crohn’s disease, conclusive proof is currently lacking in this area.
Lyme Disease
Because of Beta-glucan’s ability to stimulate the immune system, it has traditionally been used for the supportive treatment of Lyme disease.
Treatment of Burns
Beta-glucan collagen matrix, which is a combination of collagen with Beta-glucan helps lessen the pain, improves healing and reduces appearance of scars in burning. While further studies are still being done to corroborate this quality, beta-glucan matrix continues to be used with rather good results as a temporary coverage for partial burns.
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Sources and Forms of Beta-glucan: |
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Beta-glucan is derived from two major sources: yeast and grains.
Concentrated yeast-derived beta-glucan is more readily incorporated into food products as compared to grain-derived beta-glucan (found in cereals such as barley and oat). The yeast-derived beta-glucan can be dissolved in water and is considered more palatable. However, research shows that oat-derived beta-glucan has enhanced therapeutic benefits. Beta-glucan can be eaten in food products, or administered via injection.
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Recommended Dosage of Beta-glucan: |
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For adults 18 years and older, beta-glucan can be taken orally for a wide range of conditions by way of cereals containing beta-glucan or concentrates containing the fiber (typically eight to fifteen grams of beta-glucan).
For hyperlipidemia, a daily dose of 3-16 grams of beta-glucan has been found to be moderately effective in lowering levels of HDL (bad cholesterol) and for high blood pressure.
The general recommended daily dose is 5.52 grams of Beta-glucan.
There is no proven safe or effective dose for Beta-glucan in children aged 18 and younger, and its use is not recommended.
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Safety and Side Effects of Beta-glucan: |
When taken orally, both fungal as well as yeast beta-glucens appear to be well tolerated and have minimal adverse side effects and are under the Generally Regarded as Safe (GRAS) category in the United States.
However, here are a few of precautions that need to be taken into consideration before administering Beta-glucan:
- Beta-glucan should be used cautiously with AIDS or AIDS-related complex (ARC).
- It should not be given to individuals with a known hypersensitivity or allergy to beta-glucan.
- Beta-glucan is best avoided as far as possible by women who are pregnant or breastfeeding due to inconclusive proof regarding its safe usage.
- Although not proven beyond a doubt, studies indicate that co-administration of Beta-glucan with any non-steroidal anti-inflamatory drugs (NSAIDS) or aspirin could cause severe gastrointestinal damage resulting in eneteric-induced bacterial peritonitis.
- When administered intravenously, eta-glucan could result in a whole slew of adverse effects including headaches; dizziness; high or low blood pressure; nausea and vomiting; rash; hives; excessive urination, constipation or diarrhea.
- Preliminary evidence suggests that intravenous beta-glucans in the microparticulate form could result in serious side effects including microembolization, hepatosplenomegaly and formation of granuloma.
- Patients who receive yeast Beta-glucans may develop the onset of keratoderma of the palms and the soles during the 1st 2 weeks of commencing therapy but it gets resolved about 2-4 weeks after it is discontinued.
- Though there is no conclusive proof, it is suggested that Beta-glucan may be associated with lung inflammation and inflammatory airway disease.
- Although the effects are not well studied in humans, other studies suggest that Beta-glucan may have the effect of altering blood pressure. Patients who take supplements or herbs for high or low blood pressure should consult with a qualified health care professional including a pharmacist before combining therapies.
Behall KM, Scholfield DJ, Hallfrisch J. Effect of beta-glucan level in oat fiber extracts on blood lipids in men and women. J Am Coll Nutr. 1997;16:46-51.
Bell S, Goldman VM, Bistrian BR, et al. Effect of beta-glucan from oats and yeast on serum lipids. Crit Rev Food Sci Nutr. 1999;39:189-202.
Braaten JT, Wood PJ, Scott FW, et al. Oat beta-glucan reduces blood cholesterol concentration in hypercholesterolemic subjects. Eur J Clin Nutr. 1994;48:465-74.
Cooper CJ, Turcasso N. Immunostimulatory Effects of Beta-1, 3-glucan and Acemannan. Medical University of South Carolina.
Czop JK. The role of beta-glucan receptors on blood and tissue leukocytes in phagocytosis and metabolic activation. Pathol Immunopathol Res. 1986;5:286-96.
Czop JK, Kay J. Isolation and characterization of beta-glucan receptors on human mononuclear phagocytes. J Exp Med. 1991;173:1511-20.
Czop JK, Puglisi AV, Miorandi DZ, Austen KF. Perturbation of beta-glucan receptors on human neutrophils initiates phagocytosis and leukotriene B4 production. J Immunol. 1988;141:3170-6.
Estrada A, Yun CH, Van Kessel A, et al. Immunomodulatory activities of oat beta-glucan in vitro and in vivo. Microbiol Immunol. 1997;41:991-8.
Nicolosi R, Bell SJ, Bistrian BR, et al. Plasma lipid changes after supplementation with beta-glucan fiber from yeast. Am J Clin Nutr. 1999;70:208-12.
Uusitupa MI, Ruuskanen E, Makinen E, et al. A controlled study on the effect of beta-glucan-rich oat bran on serum lipids in hypercholesterolemic subjects: relation to apolipoprotein E phenotype. J Am Coll Nutr. 1992;11:651-9.
Wood PJ. Physicochemical properties and physiological effects of the (1----3)(1----4)-beta-D-glucan from oats. Adv Exp Med Biol. 1990;270:119-27.
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Frequently Asked Questions on Beta-glucan: |
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How much beta-glucan should I take for the treatment of my cardiovascular disease?
For cardiovascular disease, the effects of 4 daily servings of 2 dietary fibers – psyllium (1.78 grams per serving) and beta-glucan (0.75 grams per serving) are currently being studied. Increased amounts of Beta-glucan and fiber may result in enhanced effects.
Under what circumstances should I be using beta-glucan injections?
Beta-glucan injections are still being studied and should strictly only be given under the supervision of a pharmacist or any other qualified healthcare professional. 1-10 milligrams of the fungal Beta-glucan schizophyllan (SPG) have been administered over 10-30 minutes, once or twice weekly in the treatment of HIV infection.
For patients who are undergoing surgical procedures and who are considered high risk, 0.52 milligrams per kilogram of PGG-glucan has been administered one to six hours before surgery. This dose is then repeated at regular intervals of 4 hours, 48 hours and 96 hours post surgery.
To prevent infection in trauma patients undergoing exploratory surgical procedures, a daily dose of 50 milligrams per square meter of soluble yeast-derived Beta-glucan is recommended over a period of seven days.
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Additional Research on Beta-glucan: |
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Beta-glucan and Cholesterol Management
Biörklund M, Holm J, Onning G. Serum lipids and postprandial glucose and insulin levels in hyperlipidemic subjects after consumption of an oat beta-glucan-containing ready meal. Ann Nutr Metab. 2008;52(2):83-90.
Park SY, Bae IY, Lee S, Lee HG. Physicochemical and hypocholesterolemic characterization of oxidized oat beta-glucan. J Agric Food Chem. 2009 Jan 28;57(2):439-43.
Smith KN, Queenan KM, Thomas W, Fulcher RG, Slavin JL. Physiological effects of concentrated barley beta-glucan in mildly hypercholesterolemic adults. J Am Coll Nutr. 2008 Jun;27(3):434-40.
Vetvicka V, Vetvickova J. Physiological effects of different types of beta-glucan. Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub. 2007 Dec;151(2):225-31.
Beta-glucan and Hypoglycemia / Diabetes
Fantuzzi G, Sacco S, Ghezzi P, Dinarello CA. Physiological and cytokine responses in IL-1 beta-deficient mice after zymosan-induced inflammation. Am J Physiol. 1997 Jul;273(1 Pt 2):R400-6.
Rami B, Zidek T, Schober E. Influence of a beta-glucan-enriched bedtime snack on nocturnal blood glucose levels in diabetic children.
J Pediatr Gastroenterol Nutr. 2001 Jan;32(1):34-6.
Skoglund G, Ahrén B, Rerup C, Stenström A, Lundquist I. Glycogen and glycogen-hydrolysing lysosomal enzyme activity in mouse liver: effects of fasting, adrenoceptor antagonism and insulin-induced hypoglycaemia. Acta Physiol Scand. 1987 Oct;131(2):257-63.
Würsch P, Pi-Sunyer FX. The role of viscous soluble fiber in the metabolic control of diabetes. A review with special emphasis on cereals rich in beta-glucan. Diabetes Care. 1997 Nov;20(11):1774-80.
Beta-glucan and Crohn's Disease
Chiba M, Mikami K, Iizuka M, Yukawa M, Watanabe S, Takazoe M, Fukushima T, Koganei K, Kishibe T. Elevated plasma (1-->3)-beta-D-glucan, a fungal cell wall constituent, in a subgroup of Crohn disease. Scand J Gastroenterol. 2001 Apr;36(4):447-8.
Simonsen T, Elmgreen J. Defective modulation of complement in Crohn's disease. C3b opsonization of zymosan by the alternative pathway. Scand J Gastroenterol. 1985 Sep;20(7):883-6.
Beta-glucan and the treatment of Burns
Delatte SJ, Evans J, Hebra A, Adamson W, Othersen HB, Tagge EP. Effectiveness of beta-glucan collagen for treatment of partial-thickness burns in children. J Pediatr Surg. 2001 Jan;36(1):113-8.
Toklu HZ, Sener G, Jahovic N, Uslu B, Arbak S, Yeğen BC. Beta-glucan protects against burn-induced oxidative organ damage in rats. Int Immunopharmacol. 2006 Feb;6(2):156-69.
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