This survey is designed to investigate the effect of highland barley β-glucan supplementation on the regulatory of blood glucose, gut microbiota and cardiovascular risk fators in subjects with hyperglycemia.

Highland barley β-glucan belongs to the group of prebiotics and has been found to be associated with multiple health benefits. However, its protective role in subjects with hyperglycemia are remain unclear. This study aims to examine the effect of 8-week prebiotics supplementation on glucose management in subjects with hyperglycemia. By understanding the mechanism by which prebiotics exert the beneficial effects, we can better control the rising prevalence of hyperglycemia, which is a major risk factor for cardiovascular diseases.

Inclusion Criteria:

1. Age: 30-65 years old
2. Fasting venous plasma glucose ≥5.6mmol/L OR plasma glucose 2 h after an oral glucose load ≥7.8mmol/L OR glycosylated hemoglobin ≥5.7% OR newly diagnosed diabetes without hypoglycemic drugs using
3. BMI≥18 kg/ m2

Exclusion Criteria:

1. Receiving or have been treated with hypoglycemic drugs or insulin.
2. Complications including cardiovascular and cerebrovascular diseases such as coronary heart disease and stroke.
3. Severe liver or renal insufficiency (alanine aminotransferase, aspartate aminotransferase or alkaline phosphatase is greater than 3 times the upper limit of normal OR GFR<30ml/min/1.73m2).
4. Autoimmune diseases or thyroid diseases.
5. Women who are pregnant, nursing, or prepare to give birth during the trail.
6. Malignant disease, infectious disease, inflammatory disease and advanced liver disease.
7. Mental or intellectual abnormalities, unable to sign informed consent.
8. Complications including chronic gastrointestinal disease; or suffered from acute gastrointestinal diseases within 1 months before screening visit.
9. Received antibiotics, probiotics within 3 months before screening visit or throughout the trail.
10. Major operations were performed within six months of screening visit, or will be made during the trial.
11. Alcohol abuse (alcohol intake>60g/d for male and alcohol intake>40g/d for female)

Participants, investigators and care providers at the scene are all blinded to the allocation of treatment group. Data collected will be analyzed by another investigator who is blinded to the study design.