Beta-Glucan: Uses, Side Effects, Interactions, and Dosage

beta-glucan benefits 

Beta-glucans may reduce duration, of respiratory infections, like the common cold  

Competitive endurance athletes experience upper respiratory tract infections (URTIs), like the common cold, at a higher rate than causal or recreational participants.

Epidemiologic data suggests that endurance athletes are particularly susceptible to infection  during periods of heaving training and the 1- to 2-week period after a long event, like a marathon or other endurance-type race.  (Nieman) (Shephard)

Researchers have found that there is a dramatic decrease (falling below exercise and pre-exercise levels) in immune response within two hours of exercise. Many athletes and trainers describe this period as an  “open window,” or a brief period of immunosuppression. (Nieman)

Despite abundant research into immune health and possible preventatives, there aren’t many proven ways to stay healthy after intense exercise.

  • Good hygiene is one straightforward preventative measure against infection.
  • Another is to document your rate of illness and compare it to your training log.
  • You might find that you are overtraining, or training at an intensity or duration that makes recovery impossible, which also increases frequency of illness.

However, as hard as you try to avoid getting sick, you still might find yourself with a URTI during training season. If so, make sure to get proper sleep and nutrition, and try supplementing with beta-glucans.

What are beta-glucans?

beta-glucan side effects

Beta-glucans are sugars found in the cell walls of bacteria, fungi, yeasts, algae, lichens, and plants. They occur often in our diets in fibrous cereals derived from oat, barley, wheat, and rye, like bran flakes and oatmeal.

Interestingly, before research on beta-glucans and URTIs, they were already being used to treat a wide variety of illnesses, with the most notable being high cholesterol, infection after surgery, cervical cancer, weight loss, and reduction of RTIs.

The first study examining the relationship between beta-glucans and RTIs was performed on a group of 215 children.

  • They were administered a beta-glucan syrup every morning for three months.
  • Researchers documented a more than 50% reduction of RTIs in over 70% of the experimental group, with the rate of illness declining from 8.9 episodes to 3.6. (Jesenak)

Several clinical studies have been performed, as well.

  • Auinger et al. studied the effect of a yeast-derived beta-glucan in 162 healthy adults. Researchers found beta-glucans reduced illness by 25%. (Auinger)

Other studies have found that beta-glucans failed to reduce incidence of illness, but did reduce severity.

  • A 2019 study examined 299 healthy men and women who reported at least three URTIs during the previous year.
  • They were randomized to receive a placebo or 900 mg of yeast beta-glucan daily for 16 weeks.
  • Both the placebo and the beta-glucan group experienced at least one clinically confirmed URTI.

However, the researchers note that severity was less pronounced in the beta-glucan group and that the physical symptoms were reduced, as well as improved blood pressure. (Dharsono)

Similar findings have been reported elsewhere, leaving many researchers to conclude that beta-glucans could be a safe way to both treat and prevent RTIs. (Jesenak)

Beta-glucans Benefits 

beta-glucan dosage

Not only could beta-glucans reduce RTIs in the general population, but they may offer athletes a competitive advantage by reducing incidents of upper respiratory infections, like the common cold.

  • In one study, supplementation decreased the incidence of upper respiratory tract infection compared to placebo in elite athletes (p < 0.001) while increasing natural killer cell numbers.  (Bergendiova)
  • In one study of 75 marathon runners, researchers administered either 500 mg, 250 mg, or a placebo for 4 weeks. They found that not only did beta-glucan reduce symptoms of URTIs, but also decreased feelings of confusion, fatigue, and anger. (Tallbot) 

Some studies focused on the effects of beta-glucans on biomarkers of immune response, rather than incidence and severity of illness.

  • In one study, a group of 60 recreationally active men and women supplemented  baker’s yeast beta-glucan for 10 days.
  • Researchers found an increase of biomarkers like (CD14+) and pro-inflammatory monocyte (CD14+CD16+) in the beta-glucan group, as well as an increase in biomarkers that suggest that beta-glucans improve immune response following strenuous exercise. (Carpenter) 

Other researchers found that beta-glucan supplementation helped prevent the decline of natural killer cells (white blood cells), which has been observed after intense exercise. (Bobovcak)

How do beta-glucans work?

Beta-glucans are acid resistant, allowing it to move through the stomach relatively unchanged.

Macrophages, or large white blood cells, reside in the lining of the stomach. They are armed with beta-glucan receptors, and transport the molecule and activate it in the process.

The beta-glucan then moves to lymph nodes where it is able to release proteins (cytokines) that activate a systemic immune response. (Rahar)

Is beta-glucan safe?

The commercially available form of beta-glucan, Wellmune, is considered safe by the U.S. Food and Drug Administration (FDA). You can find out more about the research behind Wellmune here.

How and when to take beta-glucan to reduce illness

According to researchers, beta-glucan is best absorbed when taken on an empty stomach.

As a dietary supplement, take 250 mg of yeast beta-glucan per day.

Beta-glucan interactions with other compounds

Beta-glucans increase immune response, making it ill-advised to supplement beta-glucan while taking immunosuppressants. (WebMD)

Where can I find beta-glucan?

You can ingest beta-glucans through your diet, although cooking foods will reduce the content of beta-glucans. Foods rich in beta-glucan include

  • Cereal made of oats, wheat, and barley
  • Baker’s yeast
  • Mushrooms like maitake, shiitake, and reishi

Or, try supplementing beta-glucan with ImmuneElite, a 250mg capsule that has clinically demonstrated a significant reduction in URTIs, the symptoms of URTIs, and total sick days in athletes.

About The Author: 

Matt Mosman (MS, CISSN, CSCS) is a research scientist, endurance athlete, and the founder and Chief Endurance Officer at EndurElite. Matt holds his B.S. in Exercise Science from Creighton University and his M.S. in Exercise Physiology from the University of California.  Matt and his family reside in Spearfish South Dakota, where they enjoy running, mountain biking, camping, and all the outdoor adventures Spearfish has to offer.


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  • Why Athletes Might Be At Greater Risk of Illness

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