Effects of Chronic Green Tea Flavonoid Supplementation of Biomarkers of Oxidative Stress and Inflammation, and Body Fat Composition Among Subjects with Metabolic Syndrome

Principal Investigator: Timothy Lyons, MD (OUHSC)

&

Arpita Basu, PhD (Oklahoma State University)

Abstract:

Oxidative stress and inflammation play a pivotal role at all stages of atherosclerosis and the subsequent development of coronary heart disease (CHD). Metabolic syndrome (MeS), a constellation of several risk factors including dyslipidemia, hypertension, central adiposity, and impaired fasting glucose, is also a condition associated with increased inflammation and hypercoagulation. Subjects with MeS also possess an increased risk of developing Type 2 diabetes and CHD. Epigallocatechin-3-gallate (EGCG), a major bioactive polyphenol present in green tea is a potent antioxidant and also an anti-inflammatory agent. The main objectives of this study is to analyze the effects of green tea beverage consumption versus green tea extract supplementation on biomarkers of oxidative stress and inflammation in subjects with MeS, and to analyze any difference in body fat composition, fasting blood glucose and lipid levels among the control group, green tea beverage group, and green tea extract group. 60 subjects with MeS (n=20/group), will be recruited through the GCRC at Oklahoma Health Sciences Center at Oklahoma City. Subjects will be randomly assigned to the following 3 groups- control (usual diet), green tea beverage (4 cups/day), and green tea supplement (500 mg EGCG). Subjects will be recruited by flyers at GCRC, OUHSC. Following an intial screening by telephone questionnaire, subjects will be scheduled for the screening visit, and subsequent visits as follows-

Screening- Subjects will be asked to sign the consent form, and height, weight, blood pressure, waist circumference will be measured. Fasting blood draw (13mL) will be done by a certified phlebotomist to analyze fasting glucose, lipids, liver enzymes, thyroid stimulating hormone (TSH), body urea nitrogen (BUN), and creatinine, Hb, WBC, platelets. Subjects who qualify will be confirmed over the telephone and will be asked to return for the supply of supplements or green tea. Those in the green tea beverage group will be supplemented on a daily basis.

2 weeks- Subjects return at 2 weeks for supply of tea/capsules, turn in 3-day food records, and general discussion with the research staff regarding the study/compliance.

4 weeks- Subjects return at 4 weeks for supply of tea/capsules, turn in 3-day food records. Fasting blood draw (45mL) will be done by a certified phlebotomist for subsequent analysis of glucose, lipids, liver enzymes, insulin, biomarkers of oxidative stress & inflammation, and baseline catechin analysis. Body weight, body composition, and blood pressure will be recorded. General discussion with the research staff regarding the study/compliance.

6 weeks- Subjects return at 6 weeks for supply of tea/capsules, turn in 3-day food records, and general discussion with the research staff regarding the study/compliance.

8 weeks- Subjects return at 8 weeks for final visit, turn in 3-day food records. Fasting blood draw (45mL) will be done by a certified phlebotomist for subsequent analysis of glucose, lipids, liver enzymes, insulin, biomarkers of oxidative stress & inflammation, whole blood cytokines, and baseline catechin analysis. Body weight, body composition, and blood pressure will be recorded. General discussion with the research staff regarding the study/compliance. Subjects will be compensated for $30 at each visit (screening, 2, 4, 6, & 8 weeks).

Plasma and serum samples will be collected for analyses of oxidized LDL, nitrotyrosine, lipid peroxidation, and myeloperoxidase. Biomarkers of inflammation like IL-6, CRP, ICAM-1, and TNF will also be measured. A radioimmunoassay will be performed to measure adiponectin levels, an anti-inflammatory cytokine. HOMAIR will be calculated to evaluate insulin resistance. Whole blood cytokine analysis, following LPS challenge will be done with fresh blood samples. To monitor compliance, plasma flavonoids will be analyzed using HPLC procedure. Repeated measures ANOVA will be performed to detect differences among treatments at different time points, followed by pair-wise comparisons. α will be set at 5% for statistical significance.

Participant Inclusion Criteria:

• A waist circumference of greater than 40 inches in men or 35 inches in women
• HDL less than 40 mg/dL in men or 50 mg/dL in women
• Blood pressure greater than 130/85 mmHg or are on blood pressure medication
• Triglycerides greater than 150 mg/dL
• Fasting blood glucose greater than 100mg/dL but less than 126 mg/dL

Participant Compensation:

Yes

Contact Information:

Misti Leyva, MS RD/LD 271-4272 x 42732 (OUHSC, OKC) or misti-leyva@ouhsc.edu

Arpita Basu, PhD 405-744-4437 (OSU, Stillwater) or arpita.basu@okstate.edu When inquiring, please mention the Green Tea study.