Beta Glucan

Possible Beta 1,3/1,4 D-Glucan Benefits

Cholesterol Levels and Heart Disease

• In various studies, consuming 3-6 g of oat-derived beta-glucan extract per day lowered total blood cholesterol and LDL cholesterol in individuals with normal or increased cholesterol levels for 5-9% for as long as beta-glucan was consumed, but did not lower triglycerides or raise HDL cholesterol ^[1,5,6,7,8]. The US Food and Drug Administration (FDA) allows the claim “may reduce the risk of heart disease” on the labels of certain oat and barley food products ^[9].
• Oat bran and, at a lesser extent, oatmeal, can reduce the total and LDL cholesterol blood levels. In one study, consuming oat bran in a dose 2 oz  or 57 g dry, which is 1.5 cup or 355 mL cooked per day for six weeks lowered LDL cholesterol in individuals with increased cholesterol by 16% in average ^[10].
• In another study, barley extract, pearl barley, barley bran flour or barley beverages, consumed in doses that provided 3-10 g beta-glucan/day for 4-12 weeks lowered the total and LDL cholesterol and triglycerides, but did not alter HDL cholesterol ^[14].

The cholesterol-lowering effect of beta-glucan may increase with its viscosity, solubility, dose and molecular weight (oat>barley glucan) and may gradually decrease after weeks/months of taking ^[1,10,18]. Beta-glucan added to juice may have greater effect than beta-glucan in bread or cookies ^[1,11]. Additionally, different people may respond differently to beta-glucan ^[1].

Supplements Containing Insoluble Yeast Beta 1,3/1,6 D-Glucan

Beta-glucan supplements in the EU and U.S. usually contain insoluble beta 1,3/1,6 D-glucan derived from baker’s yeasts (Saccharomyces cerevisiae). The digits 1,3 and 6 identify positions of carbons in glucose molecules involved in bonds.

In one study, yeast derived beta 1,3/1,6 glucan decreased blood LDL levels for 8% and increased HDL levels for 16%, but there was no control group involved, so the results are questionable ^[1]. Yeast-derived beta-glucan, which is insoluble and of low viscosity, does not likely significantly reduce glucose spikes after carbohydrate meals.

Supplements containing oat- and barley-derived beta-glucan are also available.

Insufficient Evidence

Insufficient studies have been done to prove the effect of beta-glucans from any source in prevention or treatment of obesity ^[8,18], cancer ^[8,12], upper respiratory tract infections (common cold, flu) ^[13], high blood pressure (except in obese people) ^[15], ulcerative colitis ^[16], high blood glucose levels  and diabetes ^[2,3,4,17], fibromyalgia, chronic fatigue syndrome (CFS), rheumatoid arthritis, HIV/AIDS, wrinkles, liver problems, multiple sclerosis, asthma, allergies or physical and emotional stress. There is insufficient scientific evidence about the effectiveness of medicinal mushrooms Maitake (Grifola frondosa) or Shiitake (Lentinula edodes), containing beta 1,3/1,6 D-glucan, in treatment of any disease ^[19,20]. There is insufficient evidence about the effect of beta glucan on weight loss ^[8,18].

Beta-Glucan Safety

Beta-glucan derived from mushrooms ^[21] and barley ^[24] is Generally Considered As Safe (GRAS) by the US Food and Drug Administration (FDA); FDA has not determined the GRAS status for baker’s yeast ^[22] and oat bran ^[23], but it has approved its use.

During Pregnancy

Not enough studies have been done to determine safety of beta-glucan during pregnancy and breastfeeding ^[19].

Side Effects

When consuming in high amounts, beta-glucan may cause mild abdominal bloating and excessive gas (flatulence) ^[24]. Allergic reactions to beta-glucan are possible ^[24].

Frequently Asked Questions

1. Is barley vegan and gluten-free?

• Yeast-derived beta-glucan is not vegan but is gluten-free.
• Barley-derived beta-glucan is vegan but may not be gluten-free.
• Oat-derived beta-glucan is vegan and, when not contaminated by wheat during processing, should be gluten-free.

Related Nutrients

• Dietary fiber
• Prebiotics