Background
Ingestion of tea flavonoids found in both green and black tea is linked to cardiovascular health benefits such as lowering
serum lipids. Evidence for a cholesterol-lowering benefit of green or black tea consumption from human intervention studies
is, however, conflicting and active components responsible for the effect have not yet been clearly identified.
Aim of the study
In a randomized, double-blind, placebo-controlled, parallel design study the effects of ingesting a purified black tea theaflavins
(TFs) powder alone or in combination with catechin (TFs/catechins) on lowering serum total (TC) and LDL-cholesterol (LDL-c)
were assessed.
Methods
In total, 102 mildly to moderately hypercholesterolemic (TC and LDL-c: 5.70 ± 0.74 and 3.97 ± 0.61 mmol/L, respectively) subjects
(67 men and 35 women) were randomly assigned to consume once daily one capsule of one of the 3 treatments: TFs (providing
77.5 mg), TFs/catechins (providing 75.0 mg TFs plus 150.0 mg catechins and 195.0 mg of other polyphenols), or placebo (cellulose).
Results
Serum TC and LDL-c concentrations did not differ significantly among the 3 treatments as assessed at 4, 8, and 11 weeks using
analysis of covariance (p = 0.1187 and p = 0.1063, respectively). Although changes over time from baseline to week 11 were significant for TC and LDL-c (p = 0.0311 and p = 0.0269, respectively), this decrease over time was seen in the TFs and placebo groups.
Conclusion
In this human intervention study, no statistically significant LDL-c lowering effect was seen with either TFs alone or the
TFs/catechins combination as compared to placebo. Based on these findings it cannot be concluded that tea flavonoids such
as theaflavins and catechins are responsible for a putative cholesterol-lowering effect of black tea, at least not with the
daily dose applied in the present study.
Keywords Black tea - Theaflavins - Catechin - Cholesterol-lowering - Healthy individual