Effect of Tea Theaflavins and Catechins on Microvascular Function

Abstract

Beneficial effects of flavonoid-rich black and green tea on macrocirculation have been well established. Theaflavins are unique to black tea as they are formed from catechins during the enzymatic oxidation of tea leaves. The study was performed to gain more insight into the effects of theaflavins on microcirculation and to compare effects with another important flavonoid class, the green tea derived catechins, which have been reported to improve vascular function. Twenty-four healthy subjects were included in a double-blind, placebo-controlled, randomised, cross-over study. On six different days, subjects received capsules with a single dose of catechins (500 mg), four varying doses of theaflavins (100 to 500 mg) or placebo. Microcirculation was assessed after each treatment by Pulse Amplitude Tonometry (EndoPAT) at baseline and 2, 4 and 6 h after test product intake. The EndoPAT reactive hyperemia response was improved by 500 mg catechins (reactive hyperemia index (RHI): 0.2; p = 0.04) and by 500 mg theaflavins (RHI: 0.19; p = 0.06) compared to placebo. Also, 300 mg theaflavins increased the RHI (0.28; p = 0.02), but no effects were observed at lower doses. The study suggests moderate effects of single doses of catechins and theaflavins on peripheral microcirculation.

Assessing the effects of a short-term green tea intervention in skin microvascular function and oxygen tension in older and younger adults

“…This expands on earlier findings by Fuchs et al (2014) who reported significant improvements in hyperaemia following a 12-day intervention.…”

Orange juice–derived flavanone and phenolic metabolites do not acutely affect cardiovascular risk biomarkers: a randomized, placebo-controlled, crossover trial in men at moderate risk of cardiovascular disease

“…Although cardiovascular risk biomarkers were assessed at 5 h after intake, which is the anticipated peak flavanone plasma concentration [based on previous flavanone pharmacokinetic data ( 15 )], it remains possible that beneficial cardiovascular effects could have been observed after a more prolonged (5–24 h or several weeks/mo) exposure. In addition, the present study used the RH-PAT index to measure fingertip endothelial function, and although flow-mediated dilatation of the brachial artery is generally accepted as a more sensitive method of assessing endothelial function ( 37 ) and CVD risk ( 38 ), an improvement in the RH-PAT index has recently been observed after an acute flavonoid intervention ( 39 ).…”

Effect of oral theaflavin administration on body weight, fat, and muscle in healthy subjects: a randomized pilot study

“…14,15) Fuchs et al (2014) reported that theaflavin administration increased peripheral microcirculation. 16) In addition, single oral administration of theaflavins significantly increased energy expenditure and upregulated uncoupling protein-1,3 and peroxisome proliferator-activated receptor gamma coactivator-1α in brown adipose tissue. 17) These results raised the possibility that black tea polyphenols reduced lipid absorption in the intestine and activated energy consumption by upregulating metabolic genes, resulting in reduced body fat.…”