Daily vitamin D3 and yeast beta-glucan for blood sugar control and heart disease risk in people with type 2 diabetes

Effects of Vitamin D3 and Yeast Beta-Glucan Supplementation on Glycemic Control and Cardiovascular Disease Risk in Patients With Type 2 Diabetes: A Randomized Double-Blind Controlled Trial

This study will test whether taking daily vitamin D3 (1600 IU) and/or yeast beta-glucan (600 mg) helps improve blood sugar control and lowers predicted 10-year heart disease risk in people aged 40–79 with type 2 diabetes.

Quick facts

• Phase: NA
• Study type: Interventional
• Enrollment: 2500 (estimated)
• Ages: 40 Years to 79 Years
• Sex: All
• Sponsor: Huazhong University of Science and Technology (other)
• Locations: 5 sites (Nanning, Guangxi and 4 other locations)
• Trial ID: NCT06861062 on ClinicalTrials.gov

What this trial studies

This randomized, double-blind, placebo-controlled 2×2 factorial trial will enroll about 2,500 adults aged 40–79 with type 2 diabetes and randomly assign them to daily vitamin D3, yeast β-glucan, both, or double placebo for two years. Participants will take four capsules daily and complete questionnaires, physical exams, and blood, urine, and feces sample collections at study centers. Primary outcomes are changes in glycemic control and predicted 10-year ASCVD risk, while secondary outcomes include cardiometabolic risk factors, inflammatory markers, liver and kidney function, and clinical cardiovascular and microvascular events during a three-year post-intervention follow-up. The multicenter design in China allows long-term monitoring to detect both metabolic and clinical effects.

Who should consider this trial

Good fit: Adults aged 40–79 with physician-diagnosed type 2 diabetes who can attend one of the participating centers and commit to a two-year intervention plus three-year follow-up are the intended participants.

Not a fit: Individuals with recent major cardiovascular events, advanced diabetic microvascular complications (for example eGFR <30 mL/min/1.73 m², proliferative retinopathy, or severe neuropathy), or recent cancer are excluded and are unlikely to be helped by participation.

Why it matters

Potential benefit: If effective, these low-cost supplements could modestly improve glucose control and reduce long-term cardiovascular risk for people with type 2 diabetes.

How similar studies have performed: Smaller trials and observational studies have reported mixed or modest effects of vitamin D or dietary beta-glucans on glucose and cardiometabolic markers, but large long-term randomized trials are limited.

Eligibility criteria

Inclusion Criteria:

1. Type 2 diabetes mellitus diagnosed by a physician based on the diagnostic criteria outlined in the Guideline for the Prevention and Treatment of Diabetes Mellitus in China (2024 Edition);
2. Men or women aged 40-79 years;
3. Convenient access to the study centers and permanent residence in the vicinity for the next five years;
4. Voluntary participation and signed written informed consent.

Exclusion Criteria:

1. History of clinical cardiovascular disease (including myocardial infarction, treatment or hospitalization for heart failure, stroke, and coronary revascularization) within the past 6 months;
2. History of severe diabetic microvascular complications (diabetic nephropathy with an estimated glomerular filtration rate (eGFR) \< 30 mL/(min·1.73m²), proliferative diabetic retinopathy, confirmed diabetic peripheral neuropathy with abnormal nerve conduction studies or small fiber neuropathy testing);
3. History of cancer, excluding non-melanoma skin cancer or cancers with a favorable prognosis;
4. History of kidney stones, hypercalcemia, or hyperparathyroidism;
5. History of severe liver disease, severe kidney disease, severe gastrointestinal disease, severe infectious diseases, severe sarcoidosis or other granulomatous diseases, severe mental illness, or any other condition considered unsuitable for participation judged by the clinic team;
6. Laboratory evaluation:

   * Blood calcium levels greater than or equal to the normal range for the clinical site's laboratory;
   * Alanine aminotransferase (ALT) or aspartate aminotransferase (AST) levels higher than 3 times the normal range for the clinical site's laboratory;
   * eGFR \< 30 mL/(min·1.73m²);
7. Individuals currently taking vitamin D supplements (\>400 IU/day), calcium supplements (\>600 mg/day), yeast β-glucan supplements (\>250 mg/day), or those with a history of allergy or intolerance to vitamin D or prebiotic products;
8. Participation in other clinical trials within the past 3 months;
9. Planning to become pregnant within the next five years, or currently pregnant or breastfeeding.

Where this trial is running

Nanning, Guangxi and 4 other locations

• Guangxi Medical College — Nanning, Guangxi, China (RECRUITING)
• Kailuan General Hospital — Tangshan, Hebei, China (RECRUITING)
• Sinopharm Dongfeng General Hospital — Shiyan, Hubei, China (RECRUITING)
• Huazhong University of Science and Technology — Wuhan, Hubei, China (RECRUITING)
• Sichuan University — Chengdu, Sichuan, China (RECRUITING)

Study contacts

• Principal investigator: An Pan, PHD — School of Public Health, Tongji Medical College, Huazhong University of Science and Technology
• Study coordinator: Gang Liu, PHD

Conditions: Diabetes Mellitus, Type 2, Vitamin D, yeast β-glucan, Cardiovascular Disease, glycemic control