Effect of Black Tea Intake on Blood Cholesterol Concentrations in Individuals with Mild Hypercholesterolemia: A Diet-Controlled Randomized Trial

Abstract

Habitual intake of black tea has been associated with relatively lower serum cholesterol concentrations in observational studies. However, clinical trial results evaluating the effects of black tea on serum cholesterol have been inconsistent. Several factors could explain these mixed results, in particular, uncontrolled confounding caused by lifestyle factors, e.g. diet. This diet-controlled clinical trial estimates the effect of black tea flavonoid consumption on cholesterol concentrations in 57 borderline hypercholesterolemic individuals (total cholesterol concentrations between 190 and 260 mg/dl (4.9 and 6.7 mmol/L)). A double blind, randomized crossover trial was conducted in Minneapolis, MN from April 2002 through April 2004, wherein key conditions were tightly controlled to minimize possible confounding. Participants consumed a controlled low-flavonoid diet plus 5 cups per day of black tea or tea-like placebo over two 4-week treatment periods. The flavonoid-free caffeinated placebo matched the tea in color and taste. Differences in cholesterol concentrations at the end of each treatment period were evaluated via linear mixed models. Differences (95% CI) in mg/dl among those treated with tea versus placebo were 3.43 (−7.08, 13.94) for total cholesterol, −1.02 (−11.34, 9.30) for low-density lipoprotein cholesterol (LDL-C), 0.58 (−2.98, 4.14) for high-density lipoprotein cholesterol (HDL-C), 15.22 (−40.91, 71.35) for triglycerides, and −0.39 (−11.16, 10.38) for LDL plus HDL cholesterol fraction. The LCL-C/HDL-C ratio decreased by −0.1 units (95% CI −0.41, 0.21). No results were statistically or clinically significant. Thus, the intake of 5 cups of black tea per day did not significantly alter the lipid profile of borderline hypercholesterolemic subjects.

Tea Consumption and Longitudinal Change in High‐Density Lipoprotein Cholesterol Concentration in Chinese Adults

“…Similar results were observed in some12, 31 but not all previous studies 30, 32. Total/HDL cholesterol reflects the balance between the cholesterol carried by atherogenic and protective lipoproteins 33.…”

The Pharmacological Activity of Camellia sinensis (L.) Kuntze on Metabolic and Endocrine Disorders: A Systematic Review

“…In one of these clinical trials, the effective dose was 2.5 g black tea and phytosterol mixture which contains 1 g plant sterols for 4 weeks [51]. However, for the other study, a specific dose is not specific, but five cups of black tea per day for two 4-week treatment periods [52]. On the other hand, the consumption of "Benifuuki" green tea, which is rich in methylated catechins (3 g of green tea extract/three times daily for 12 weeks) contributed significantly to reduce serum total cholesterol and serum LDL cholesterol compared to "Yabukita" green tea or barley infusion (placebo tea) consumers [53].…”

Effects Of Tea Consumption On Measures Of Cardiovascular Disease: A Systematic Review Of Meta-Analysis Studies And Randomised Controlled Trials

“…Eight RCTs examined the effects of tea interventions on cholesterol levels, lipid profile and distribution [6,[39][40][41][42][43][44]. In most studies 3 to 5 cups of tea were ingested daily [6,41,42,44]. One trial comprised of two 2-week treatment periods found that amongst borderline hypercholesterolemic subjects 5 cups of tea daily did not alter lipid profiles [42].…”

“…In most studies 3 to 5 cups of tea were ingested daily [6,41,42,44]. One trial comprised of two 2-week treatment periods found that amongst borderline hypercholesterolemic subjects 5 cups of tea daily did not alter lipid profiles [42]. A longer 12-week trial providing 3 cups (each 200 ml) of black tea infusate to normal healthy adults showed that triglyceride levels reduced by 35.8%, and LDL/HDL plasma cholesterol ratio reduced by 16.6% [44].…”