A diet-controlled clinical trial which attempts to provide estimates of the effect of black tea consumption on serum lipids under tightly controlled conditions, including a controlled diet. Mildly hypercholesterolemic individuals (total cholesterol levels between 4.9 and 6.7 mmol/L, 190 and 260 mg/dl), non-smoking, chronic disease-free individuals were enrolled in a 15-week, double blind, randomized crossover trial, during which they consumed a controlled low-flavonoid diet plus 5 cups of black tea or a tea-like placebo over two 4-week treatment periods.

Inclusion Criteria:

• between 45-65 years old
• mildly hypercholesterolemic (total cholesterol levels between 4.9 and 6.7 mmol/L, 190 and 260 mg/dl)
• high-density lipoprotein cholesterol (HDL-C) between 0.9 and 1.6 mmol/L (35 and 65 mg/dl)
• triglyceride (TG) concentrations below 6.8 mmol/L (600 mg/dl)
• habitually consumed a typical American diet with low dietary flavonoid intake (<4 one-half cup servings of fruits and vegetables/day) and low intake (<1 serving/day) of soy-rich foods, nuts, herbs, and spices (besides salt and pepper)
• aspartate aminotransferase (AST) between 0 and 55 mg/L
• creatinine between 70.7 and 150.3 mmol/L (0.8 and 1.7 mg/dl)
• glucose between 3.3 and 6.4 mmol/L (60 and 115 mg/dl)

Exclusion Criteria:

• current smoker
• usage of high amounts of antioxidant vitamin supplements (>3 times the Recommended Dietary Allowance (RDA) of vitamins E, C, and selenium, or >10 mg/day of beta carotene)
• had been diagnosed with diabetes, coagulation disorders, chronic pulmonary disease, current active malignancy, renal disease requiring dialysis, malabsorption, or gastrointestinal disorders, or had a history of cardiovascular disease.
• antihypertensive, immunosuppressive, cholesterol lowering, or anticoagulant medications
• consuming >3 servings of alcohol daily
• Pre-menopausal (women)