Atherosclerosis is a major risk factor for cardiovascular diseases. Recently, dysbiosis of gut microbiota has been reported to play an important role in the pathogenesis of atherosclerosis. Animal studies have demonstrated that administration of probiotics help delay the progression of atherosclerosis through several mechanisms. This trial aims to examine its protective effect in humans.

Atherosclerosis is a major risk factor for cardiovascular diseases. Recently, dysbiosis of gut microbiota has been reported to play an important role in the pathogenesis of atherosclerosis. Animal studies have demonstrated that administration of probiotics help delay the progression of atherosclerosis through several mechanisms such as reduction in endotoxemia, and enhanced production of short-chain fatty acids.

However, whether administration of probiotics also has a protective effect in subjects with metabolic syndrome (MetS), who are at high risk for developing atherosclerosis, remain unknown.

Inclusion Criteria:

• Local residents aged between 30-60 years old;
• Stable weight (<5% weight change over last 3 months);
• Central obesity defined as waist circumference ≥90 cm in males or ≥80 cm in females, Plus any two of the following four conditions i) Elevated triglycerides: serum triglycerides ≥150 mg/dL (1.7 mmol/L); ii) Reduced HDL cholesterol: serum HDL-c <40 mg/dL (1.03 mmol/L) in males or <50 mg/dL (1.29 mmol/L) in females; iii) Elevated blood pressure: systolic blood pressure ≥130 mmHg or diastolic blood pressure ≥85 mmHg; iv) Elevated fasting plasma glucose: fasting plasma glucose ≥100 mg/dL (5.6 mmol/L)
• Absence of any systemic, cardiovascular diseases, as well as infections within the previous month;
• Absence of any diet or medication that might interfere with metabolic homoeostasis and gut microbiota, especially antibiotics and probiotics 4 weeks before recruitment.

Exclusion Criteria:

• Acute illness or current evidence of acute or chronic inflammatory of infective diseases;
• Participation in regular diet program more than 2 times per week in the latest 3 months prior to recruitment;
• Mental illness rendering them unable to understand the nature, scope, and possible consequences of the study.