A Daily Beta Glucan (β-glucan) Supplement May Boost Flu Shot Benefits in Older Adults

Quick Summary

Oral supplements of various dietary fibers, including β-glucan, may boost the immune response against URTIs by increasing flu antibodies (AX) and IFN-γ levels (YBG) and altering the amount of immune-boosting bacteria in the gut (AX & OBG) following vaccination.

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This Study Summary was published on November 10, 2025.

    Written by:
    1. Beta Glucan PhD Team,

      Beta Glucan PhD Team

      Beta Glucan PhD Team

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      Key study details

      Background

      Upper respiratory tract infections (URTIs) are one of the most common infectious diseases worldwide and can be caused by a variety of viruses. The common cold is usually a mild-to-moderate URTI that can include symptoms ranging from sore throat, nasal congestion, and sneezing to fever and headache. While most URTIs result in asymptomatic or subclinical infections and recovery in a few days, URTIs can harm the quality of life of a person by causing absence from school or work and contributing to the misuse of antibiotics. Alongside drugs that manage fever and pain symptoms, such as aspirin and acetaminophen, treatments that support or boost the immune system, such as vitamins, probiotics, and herbs, have been employed to protect against infection or reduce the recovery time. Beta glucan (β-glucan) is a naturally derived carbohydrate that can be sourced from yeast, oats, barley, mushrooms, and algae, and has been explored for its potential health benefits. Due to the high incidence of URTIs, novel treatment options like Yeast β-glucan have been evaluated as potential supplements to reduce the severity of URTI symptoms and support the immune system.

      Study objective

      Evaluate whether different dietary fibers, such as β-glucan, enhance the immune response to seasonal influenza vaccination in healthy seniors (50–79 years).

      Methods

      Study ParticipantsNumber of Participantsβ-glucan Dosage milligram (mg)Study Timeline
      Adults 50-79 years old239

      Oat(OBG):500 mg 

      Yeast(YBG): 500 mg

      Shiitake(SBG): 500 mg

      5 weeks

       

      Study Design:  Additional groups that were given other natural supplements:

      • Arabinoxylan (AX): Dietary fiber found in cereal grains like wheat, rye, and oats.
      • Bacterial exopolysaccharide (EPS): Sugar molecule produced by bacteria that has many functions, including protection, nutrient uptake, and adhesion.

      Control Group: The control group was given 12 g of maltodextrin, a food additive derived from processed starches such as potatoes that commonly replaces sugar.

      Vaccine: A trivalent flu vaccine was administered to all groups 

      Researchers evaluated the following:

      Data Collection

      Antibody titers

      Protection against infection(seroprotection)

      UTRI incidences

      Microbiota

       

       

      Adverse events

      Results

      AX treatment showed a significant increase in influenza antibody titers 

      The AX treatment group was the only group with significantly higher influenza antibodies when compared to the control group.

      Fewer colds were seen in all experimental groups 

      The AX group had 1 URTI episode for every 8 URTI episodes observed in the control group

      Other groups (Oat, Yeast, and Shiitake-derived β-glucan and Bacterial exopolysaccharide) had fewer colds, but not statistically significant.  A larger study with more participants might be able to show if these other supplements play a role in reducing URTIs.

      AX, YBG, OBG, and EPS may increase the duration of the cellular immune response

      The cellular immune response plays an important role in clearing infection and reducing the severity of disease.

      AX, YBG, OBG, and EPS maintain interferon gamma (IFN-γ) levels, cytokine (i.e., chemical messenger) that plays a role in activating a targeted immune response to clear viral infections. post-vaccination compared to the control group.

      β-glucan increased IFN-γ levels in the blood 1 week after vaccination in this study. It is important to note that other studies have provided conflicting data on the effect β-glucan has on  IFN-γ levels. One suggests that administration of YBG for 10 days could increase IFN-γ levels in healthy adults.. While another study shows YBG did not increase IFN-γ levels in 15 males.

      AX and OBG increase the abundance of a bacterium that may have immune-boosting properties

      AX and OBG increased the relative abundance of the Parasutterella bacteria species in fecal samples

      The immune-boosting properties of Parasutterella have not been fully uncovered, but one study suggests this bacterium does not directly influence the cellular immune response in the gut, but may play a role in modulating the abundance or the function of other bacteria in the gut that have been shown to impact the immune response.

      All supplements at the dosage used in the study are safe for oral consumption & do not cause adverse events

      No adverse events were reported for all groups.

      Mild stool softening was reported in YBG, SBG, and AX treatment groups. 

      Our take

      Takeaways
      Oral supplements of various dietary fibers, including β-glucan, may boost the immune response against UTRIs by increasing flu antibodies (AX) and IFN-γ levels (YBG) and altering the amount of immune-boosting bacteria in the gut (AX & OBG) following vaccination. 

      Limitations

      Small study size

      Small sample sizes per group (40 people) reduced the ability of the researchers to identify the significance of their findings after making multiple comparisons due to having so many groups

      Dosages for each of the treatment options are different

      Having different dosages for each group makes it harder to make equal comparisons across different treatment groups

      This summary is based on peer-reviewed scientific research. We use AI tools to help condense complex studies, but all content is reviewed and approved by qualified experts before publication.

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