Study of the Preventive Effects and Mechanisms of Yeast β-Glucan on Upper Respiratory Tract Infections

Launched by LANZHOU UNIVERSITY · Jul 18, 2025

Keywords

ClinConnect Summary

This clinical trial is looking at whether a natural supplement called yeast β-glucan can help prevent upper respiratory tract infections, like the common cold, in people who have ongoing allergy symptoms affecting their nose and eyes (called persistent allergic rhinitis). The study will include university students aged 18 to 35 who experience regular allergy symptoms such as sneezing, a runny or blocked nose, and itchy eyes. The goal is to see if taking yeast β-glucan daily can reduce the number or severity of these infections and to understand how it might work in the body.

If you join the study, you will be randomly placed into one of two groups—either taking yeast β-glucan capsules or identical placebo capsules (which don’t contain the active ingredient) every day for 12 weeks. Throughout the study, you’ll keep track of any cold or respiratory symptoms using simple questionnaires, and the research team will check in with you weekly to monitor your allergy symptoms and overall well-being. You’ll also have some health measurements taken and provide blood, urine, and stool samples at the start and end of the study. The study is designed so that neither you nor the researchers will know which capsules you are taking, to make the results as reliable as possible. This research may help show if yeast β-glucan is a safe and effective way to protect people with allergies from getting sick.

Gender

ALL

Eligibility criteria

• Inclusion Criteria:
• • 1. Aged between 18 and 35 years;
• • 2. Meeting the symptom criteria for persistent allergic rhinitis (AR) as defined in the Chinese Guidelines for Diagnosis and Treatment of Allergic Rhinitis (2022, Revised Edition): (1) Symptoms: Two or more of the following-paroxysmal sneezing, watery rhinorrhea, nasal itching, and nasal congestion-lasting continuously or cumulatively for at least 1 hour per day; ocular symptoms such as tearing, itching, and redness may also be present; (2) Persistent AR: Symptoms occur on ≥4 days per week and persist for ≥4 consecutive weeks;
• • 3. No use of probiotics, prebiotics, synbiotics, antihistamines, corticosteroids, or immunosuppressants within 1 month prior to screening;
• • 4. Willing and able to maintain usual physical activity levels and dietary patterns during the study;
• • 5. Able and willing to sign the informed consent form voluntarily.
• Exclusion Criteria:
• • 1. Use of antibiotics, osmotic laxatives (e.g., magnesium sulfate, lactulose), anthraquinone-containing agents (e.g., rhubarb, aloe, senna), or gastrointestinal motility-promoting drugs (e.g., metoclopramide, domperidone, cisapride) within 1 month prior to screening;
• • 2. Diagnosed with non-allergic rhinitis (e.g., vasomotor rhinitis, infectious rhinitis, hormonal rhinitis, drug-induced rhinitis), or with nasal polyps, severe nasal septum deviation, cerebrospinal fluid rhinorrhea, or aspirin-exacerbated respiratory disease (AERD);
• • 3. Patients with uncontrolled allergic comorbidities, including sinusitis, otitis media, allergic asthma, or atopic dermatitis;
• • 4. History of serious gastrointestinal diseases (e.g., severe diarrhea, inflammatory bowel disease), or gastrointestinal endoscopy within the past month;
• • 5. Diagnosed with congenital genetic disorders, primary immunodeficiency diseases, severe systemic illnesses, or malignancies;
• • 6. Influenza vaccination within the past 6 months;
• • 7. Pregnant or lactating women, or women with plans to conceive during the study period.