The objectives of this study are to examine the effects of ethnicity, central obesity and dietary components, on the human gut microbiome. The investigators hypothesize that these factors have an influence on the composition of the gut microbiome. Healthy subjects (n=35) provided stool samples for gut microbiome profiling using 16S rRNA sequencing and completed a dietary questionnaire. The serum samples were assayed for a panel of inflammatory cytokines. Their associations with central obesity were examined.

Introduction: Perturbance in the composition of human gut microbiota has been associated with metabolic disorders such as obesity, diabetes mellitus and insulin resistance. The objectives of this study are to examine the effects of ethnicity, central obesity and dietary components, on the human gut microbiome. The investigators hypothesize that these factors have an influence on the composition of the gut microbiome.

Methods: Subjects of Chinese (n=14), Malay (n=10) or Indian (n=11) ancestry, median age 39 (range:22-70 years old), were enrolled. The subjects provided stool samples for gut microbiome profiling using 16S rRNA sequencing and completed a dietary questionnaire. The serum samples were assayed for a panel of biomarkers (Interleukin-6, tumour necrosis factor alpha, adiponectin, cleaved cytokeratin 18, lipopolysaccharide binding protein and limulus amebocyte lysate). Central obesity was defined by waist circumference cut-offs in Asians.

Inclusion Criteria:

• Provision of signed written informed consent,
• Aged between 21- 75 years old,
• Body Mass Index (BMI) of > 18 kg/m2,
• Ethnic group of either Chinese, Malay or Indian as evidenced by identification card,
• Subject with absence of impaired glucose tolerance,
• Subject is healthy with no clinically significant disease or condition as determined through their medical history, physical examination; Diabetes mellitus was defined as Type 2 DM fulfilling the WHO criteria and the care of Department of Endocrinology, Changi General Hospital,
• Ability to communicate with investigator and to understand and comply with all requirements of study participation.

Exclusion Criteria:

• Subject who are viral Hepatitis (B or C) or HIV positive as per declaration,
• Subject who had bariatric surgery including lap banding, gastric sleeve surgery, cholecystectomy,
• Subject who has > 5% weight loss in the last 3 months prior to study enrolment as per declaration,
• Subject who are on 'stable' insulin sensitizers such as such as rosiglitazone, metformin for the last 3 months prior to enrolment,
• Pregnant women,
• Subject who has been treated with antibiotics within 6 weeks of enrolment,
• Subject who has usage of lactulose, dietary fibres for purpose of constipation,
• Subject with immune-compromised status; undergoing chemotherapy, on steroid,
• Subject with FMHx or PMHx of autoimmune disease, GI cancers, inflammatory bowel disease, Irritable bowel syndrome and anxiety or depression as per declaration.

Healthy volunteers recruited through advertisement or patients with type 2 diabetes mellitus from hospital records.