What Is Beta-Glucan?

Beta-glucan is a soluble fiber found naturally in cereal grains, yeast, and certain mushrooms. It is also sold as a supplement.

As a soluble fiber, beta-glucan is not digested but can slow food transit in the intestines. As a result, carbohydrates are absorbed slower, resulting in more steady blood sugar. In addition, it may remove cholesterol with it as it goes.

Dietary supplements are not regulated like drugs in the United States, meaning the Food and Drug Administration (FDA) does not approve them for safety and effectiveness before products are marketed. When possible, choose a supplement tested by a trusted third party, such as USP, ConsumerLabs, or NSF. 

However, even if supplements are third-party tested, that doesn’t mean they are necessarily safe for all or effective in general. Therefore, it is important to talk to your healthcare provider about any supplements you plan to take and to check in about any potential interactions with other supplements or medications.

Supplement Facts


  • Active Ingredient(s): Beta-glucan
  • Suggested Dose: 3 to 6 grams beta-glucan daily
  • Safety Considerations: Start slowly if supplementing and drink plenty of water

Uses of Beta-Glucan

Supplement use should be individualized and vetted by a healthcare professional, such as a registered dietitian, pharmacist, or healthcare provider. No supplement is intended to treat, cure, or prevent disease.

The FDA has approved health claims for certain soluble fibers, including beta-glucan. Given a certain type of soluble fiber and a recommended amount of fiber (or beta-glucan) per serving, food manufacturers can say this food can reduce the risk of heart disease in conjunction with a diet low in saturated fat and cholesterol.

Additionally, beta-glucan has been studied for its role in blood sugar and blood pressure management in people with diabetes and hypertension, respectively.

Beta-glucan has also been looked at for its role in helping the body fend off colds, flu, and even cancer, as well as increasing defenses against the harmful effects of stress. However, there is very little scientific support for these suggested benefits. Below are uses of beta-glucan that have some evidence of support.

Cholesterol

Beta-glucan may prevent cholesterol absorption from food, helping to lower blood cholesterol levels.

According to a 2011 report, the beta-glucan found in oats may help keep cholesterol in check. Looking at studies conducted over the previous 13 years, the report's authors determined that oat-derived beta-glucan may significantly reduce levels of total and low-density lipoprotein (LDL) or "bad" cholesterol. The authors noted that, on average, daily oat consumption is associated with 5% and 7% reductions in total and LDL cholesterol levels, respectively.

A 2014 meta-analysis found similar results. The researchers focused on studies that included at least 3 grams (g) of beta-glucan daily. They found it reduced total and LDL cholesterol but did not impact high-density lipoprotein (HDL) cholesterol levels or triglycerides.

A meta-analysis published in 2016 also found that oat beta-glucan reduced LDL cholesterol. Doses of about 6 grams daily for four weeks had a statistically significant lowering effect on LDL cholesterol levels.

The largest meta-analysis assessed 59 clinical trials comparing an oat supplement intervention to a control group. The results showed an overall reduction in total cholesterol, LDL cholesterol, blood glucose, body weight, body mass index, and waist circumference. While the differences were statistically significant, the question of clinical significance remains. For example, those in the oat supplementation group lost about 1 kilogram more weight (about 2 pounds). This underscores the importance of overall diet modification for reducing heart disease risk, which can be done in addition to adding food sources of beta-glucan.

Diabetes

Research suggests that beta-glucan may help manage diabetes by controlling blood sugar levels when incorporated into the diet.

A meta-analysis published in 2014 confirmed these findings but noted that beta-glucan alone was not enough to achieve regular blood sugar readings in people with diabetes. Additionally, a more recent meta-analysis found that long-term beta-glucan intake of an oat beta-glucan supplement at 5 grams per day improved metabolic control, including blood sugar, in people with type 2 diabetes.

Overall, beta-glucan may be helpful to use in conjunction with prescribed treatment and diet modifications. However, it should never replace standard medical care.

Blood Pressure

Dietary fiber intake may help lower blood pressure. The Dietary Approaches to Stop Hypertension (DASH) diet, which includes the intake of fruits, vegetables, and high-fiber foods, is often recommended for blood pressure management.

A meta-analysis published in 2018 evaluated studies looking at the effect of fiber on blood pressure. Overall, fiber was found to reduce systolic and diastolic blood pressure. However, it should be noted that they looked at several types of fiber, not just beta-glucan. In fact, only psyllium lowered systolic blood pressure (SBP).

Additionally, the reduction in blood pressure was small, and adding fiber should not be the only method used to manage high blood pressure.

Most people don't get enough fiber in their diet. Beta-glucans are one type of fiber found most commonly in oats and barley. Higher intakes of beta-glucan (and fiber in general) may help to reduce cholesterol, manage blood sugar levels in people with diabetes, and possibly lower blood pressure.

Although research shows improvements are statistically significant, beta-glucans alone will not be enough. If you are trying to lower cholesterol, manage diabetes, or lower your blood pressure, discuss a care plan with your healthcare provider to include (but not be limited to) diet modification and medications, if needed.

Beta-Glucan Deficiency

There are no reports of beta-glucan deficiency. Also, there is no specific Recommended Dietary Allowance (RDA) for beta-glucans.

However, there are recommendations for total fiber intake, and many Americans do not get enough fiber in their diet.

The Adequate Intake for fiber recommendations is 14 grams of fiber/1000 calories of intake. The Institute of Medicine (IOM) also has daily intake recommendations for fiber. It ranges from 21 to 26 grams of fiber daily for women and 30 to 38 grams daily for men, depending on age.

What Are the Side Effects of Beta-Glucan?

Although beta-glucan is generally considered safe, there may be a few side effects. Consuming too much fiber can cause gas, bloating, and flatulence. Be sure to drink enough water when increasing your fiber intake or adding beta-glucan.

People who eat a low-fiber diet should start with a lower dose of beta-glucan and increase it gradually. Like all sources of fiber, it may cause gastric distress, bloating, and gas if taken in larger-than-normal doses. The side effects should wear off over time, but slowly introducing it can help prevent this.

Precautions

Once on the market, supplement products often aren't as closely regulated for safety as drugs. This means that the content of some products may differ from what is specified on their product labels. Always look for supplements that have been third-party tested.

Also, keep in mind that the safety of supplements in pregnant or nursing people, children, and those with medical conditions or who are taking medications has not been established.

Dosage: How Much Beta-Glucan Should I Take?

Always speak with a healthcare provider before taking a supplement to ensure that the supplement and dosage is appropriate for your individual needs.

There is no standard dose for beta-glucan, and the amount needed differs based on the source.

Doses used in studies range from 2 to 6 grams taken orally daily for up to 12 weeks for oat beta-glucan. Doses ranging from 250 to 500 milligrams once daily for up to 12 weeks have been used for beta-glucan derived from yeast. According to the FDA, 3 grams daily of beta-glucan is the amount needed to make a health claim that the food can help lower cholesterol.

Oats, barley, and wheat
Verywell / Anastasia Tretiak

What Happens If I Take Too Much Beta-Glucan?

Taking too much beta-glucan may lead to increased gas, bloating, and stomach discomfort. It is recommended to start with a smaller dose and gradually increase your dose to prevent this.

Interactions

Discuss beta-glucan use with your healthcare provider if you are already taking medication to lower blood sugar or blood pressure. Adding beta-glucan may cause your blood sugar or blood pressure to drop too low.

Although little is known about beta-glucan's role in immune function, it may reduce the effectiveness of immune-suppressing medications.

When considering supplements, it is crucial to talk with your healthcare provider about any potential interactions with your medication regimen.

How to Store Beta-Glucan

Follow directions on the packaging for proper storage. Generally, all medications and supplements should be stored out of reach of children.

Similar Supplements

Psyllium is another form of soluble fiber that is sold as a supplement.

Frequently Asked Questions

  • Can eating mushrooms help lower cholesterol?

    While there are many different types of mushrooms, oyster and shiitake mushrooms are good sources of beta-glucan. However, there is not enough evidence to say that eating oyster mushrooms will reduce cholesterol levels. However, edible mushrooms are an excellent plant-based food with several key nutrients (e.g. vitamin D).

  • Can beta-glucan boost our immune system?

    The idea of "boosting your immune system" can be misleading. You can support a healthy immune system by getting enough sleep, exercising, eating a healthy diet, and generally taking care of yourself. Specific nutrients won't boost your immune system but can play a role in keeping it (and you) healthy. Therefore, beta-glucan taken alone will not boost your immune system.

Sources of Beta-Glucan & What to Look For

Food Sources of Beta-Glucan

Beta-glucan is found in oats, barley, rye, and sorghum. Some mushroom varieties are a good source of beta-glucan, such as oyster and shiitake mushrooms.

Beta-glucan is most abundant in raw foods, but consuming grains in this state is not possible due to processing and cooking needs, which reduce the beta-glucan content. Look for whole grains as close to their natural states as possible. For example, choose steel-cut oats over instant oatmeal or oat flour, and pearl barley over barley flour.

Beta-Glucan Supplements

Beta-glucan supplements are widely available for purchase online. They are also sold in many natural-food stores and shops specializing in dietary supplements.

Many manufacturers source their beta-glucan from substances like baker's yeast. Others use medicinal mushrooms like shiitake and maitake, which are rich in beta-glucan.

When shopping for supplements, look for brands tested by a trusted, independent third party, such as U.S. Pharmacopeia, NSF International, or ConsumerLab.

Summary

Beta-glucan is one type of soluble fiber. This fiber can be found in oats, barley, and some mushrooms or as a supplement.

In general, most people don't get enough fiber in their diet. Incorporating high-fiber foods is recommended. While a food-first approach for fiber intake is preferred, supplementation is also an option. As always, discuss your supplement use with a healthcare provider.

Although it's too soon to recommend beta-glucan supplements for health purposes, increasing beta-glucan in your diet may help enhance overall health. Remember that alternative medicine should not be used as a substitute for standard care. Self-treating a condition and avoiding or delaying standard care may have serious consequences.

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Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Jennifer Lefton, MS, RD/N, CNSC, FAND
Jennifer Lefton, MS, RD/N-AP, CNSC, FAND is a Registered Dietitian/Nutritionist and writer with over 20 years of experience in clinical nutrition. Her experience ranges from counseling cardiac rehabilitation clients to managing the nutrition needs of complex surgical patients.

Originally written by
Cathy Wong
Cathy Wong

Cathy Wong is a nutritionist and wellness expert. Her work is regularly featured in media such as First For Women, Woman's World, and Natural Health.

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