Side Effects and Benefits of Beta-glucan
May 22, 2009              
Discuss with your doctor before taking any alternative medicine. This article is for
reference only, it is not a medical advice. All rights reserved. Do not copy this article to
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Beta-Glucans are major cell wall structural components in fungi. [1]
Beta-glucan is a polysaccharide in the form of fiber and the main element of
fiber in grains such as barley, oats, yeast and mushrooms. Oat
beta-glucans are found in various breakfast cereals and snacks. However,
the yeast-derived fiber is a more concentrated source of beta-glucan than
the oat product. [6] Studies have been conducted to exam if beta-glucan
has health benefits on people suffered from high cholesterol, diabetes,
obesity, cancer, immune and heart diseases. [2]

What are the potential benefits of beta-glucan?

Some researchers consider beta-glucans as biological response modifiers
and they believe beta-glucans benefit people suffered from cancer. It is
because beta-glucans have been demonstrated to prime leukocyte
complement receptor 3 (CR3), thus enabling these cells to kill tumors
opsonised with complement fragment iC3b. Researchers found orally
administrated yeast beta-glucans are ingested and processed by
macrophages. These macrophages secrete the active moiety that primes
neutrophil complement receptor 3 to kill iC3b-opsonised tumor cells. [3, 5]

Würsch P and Pi-Sunyer FX. Nestlé Research Centre, suggested that
diabetic individuals can benefit from diets that are high in beta-glucan, a
component of oats and barley. Most cereal products, however, tend to have
a high glycemic index Cereals such as Prowashonupana barley or fractions
of oat bran are particularly high in the soluble fiber beta-glucan, which when
taken with a meal increases the viscosity of the meal bolus once it has
reached the small intestine, where the absorption of nutrients occurs. This
high viscosity delays absorption. A 50% reduction in glycemic peak can be
achieved with a concentration of 10% beta-glucan in a cereal food. A
significant lowering of plasma LDL cholesterol concentrations can also be
anticipated with the daily consumption of > or = 3 g of beta-glucan. [7]
However, studies also show inconsistent results about the health benefits of
beta-glucans may offer on people with high cholesterol. Researchers
explain the inconclusive results due to the factors such as viscosity in the
gastrointestinal tract, the food matrix and/or food processing. [4]

Though some researchers suggest viscosity as an important factor for delay
fat or glucose absorption, Theuwissen E and Mensink RP. Maastricht
University, The Netherlands, have another point of view. They observed that
four major water-soluble fiber types-beta-glucan, psyllium, pectin and guar
gum-effectively lower serum LDL cholesterol concentrations. They also
observed that the decrease in LDL cholesterol concentration is unrelated to
the differences in molecular among these water-soluble fibers, thus, they
proposed that water-soluble fibers lower the (re)absorption of in particular
bile acids. As a result hepatic conversion of cholesterol into bile acids
increases, which will ultimately lead to increased LDL uptake by the liver.
Additionally, epidemiological studies suggest that a diet high in
water-soluble fiber benefit people at risk of CVD. [8]

What are the side effects of beta-glucans?

Water-soluble fibers can prevent the absorption of cholesterol and glucose,
regardless the type of the water-soluble fibers. Thus, there is also a
possibility that beta-glucan may prevent or decrease the absorption of any
nutrients regardless the nature of the nutrients. If this is true, beta-glucan
can cause serious side effects, because of deficiency of certain nutrients.
Of course, it is just a speculation. Naumann E and co-workers from
Maastricht University, Netherlands, assayed the content of lipids and
lipoproteins, noncholesterol sterols, and fat-soluble antioxidants from
subjects who took a food product enriched with beta-glucan and concluded
that intake of beta-glucan does not affect plasma concentrations of
lipid-soluble antioxidants. [10] Well, I would say, it really depends on the
viscosity grade and amount of beta-glucan used in the food products.

Reference:
[1] Harada T, Ohno N. Tokyo University of Pharmacy and Life Science
Contribution of dectin-1 and granulocyte macrophage-colony stimulating
factor (GM-CSF) to immunomodulating actions of beta-glucan. Int
Immunopharmacol. 2008 Apr;8(4):556-66. Epub 2008 Jan 16. [2] Kim SY,
Song HJ, Lee YY, Cho KH, Roh YK. Hallym University Biomedical issues of
dietary fiber beta-glucan. J Korean Med Sci. 2006 Oct;21(5):781-9. [3] Yan
J, Allendorf DJ, Brandley B. University of Louisville, Yeast whole glucan
particle (WGP) beta-glucan in conjunction with antitumour monoclonal
antibodies to treat cancer. Expert Opin Biol Ther. 2005 May;5(5):691-702.
[4] Kerckhoffs DA, Brouns F, Hornstra G, Mensink RP. Maastricht University,
Effects on the human serum lipoprotein profile of beta-glucan, soy protein
and isoflavones, plant sterols and stanols, garlic and tocotrienols. J Nutr.
2002 Sep;132(9):2494-505. 5. Ross GD, Vetvicka V, Yan J, Xia Y,
Vetvicková University of Louisville J.Therapeutic intervention with
complement and beta-glucan in cancer. Immunopharmacology. 1999
May;42(1-3):61-74. [6] Bell S, Goldman VM, Bistrian BR, Arnold AH, Ostroff
G, Forse RA. Harvard Medical School, Effect of beta-glucan from oats and
yeast on serum lipids. Crit Rev Food Sci Nutr. 1999 Mar;39(2):189-202. [7]
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. [8] Theuwissen E, Mensink RP. Water-soluble
dietary fibers and cardiovascular disease. Physiol Behav. 2008 May
23;94(2):285-92. Epub 2008 Jan 5. [10] Naumann E, van Rees AB, Onning
G, Oste R, Wydra M, Mensink RP. Beta-glucan incorporated into a fruit drink
effectively lowers serum LDL-cholesterol concentrations. Am J Clin Nutr.
2006 Mar;83(3):601-5.