Vitamins, Minerals and Dietary Supplements
What is beta-glucan? Why do we need it?
Beta-glucan is a fiber-like polysaccharide (a complex sugar) that comes from the walls of baker's yeast, oats, barley and some mushrooms. Different varieties of beta-glucan come from different food sources.
Beta-glucan is used most often to strengthen the immune system and lower blood cholesterol levels. Research conducted as far back as the 1960s has shown that beta-glucan can stimulate the activity of white blood cells, particularly macrophages and neutrophils, which provide a first line of defense against foreign bacteria. However, since most studies of beta-glucan have been conducted in animals, its effectiveness in humans remains debatable. As for blood cholesterol, studies show that beta-glucan derived from oats or yeast is effective in reducing levels of LDL, or "bad" cholesterol, while increasing levels of HDL ("good") cholesterol.
How much beta-glucan should I take?
The amount of beta-glucan being taken depends on the condition being treated. To lower cholesterol levels, trials have used doses ranging from 2,900 milligrams to 15,000 milligrams per day. Effective amounts have yet to be determined to enhance one's immune system. However, many manufacturers (and some practitioners) usually recommend between 50 milligrams and 1,000 milligrams daily, taken on an empty stomach.
What forms of beta-glucan are available?
Beta-glucan can be derived from a variety of cereals and cereal fibers, including oats, wheat and barley. Supplements of beta-glucan are also available, usually in liquid, capsule and tablet form.
What can happen if I take too much beta-glucan? Are there any interactions I should be aware of? What precautions should I take?
Because beta-glucan is not considered an essential nutrient, deficiency and toxicity levels have not been established. As of this writing, there are no well-known drug interactions with beta-glucan. As always, make sure to consult a licensed health care provider before taking beta-glucan or any other dietary supplement or herbal remedy.
References
- 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.
- 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.
