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

Abstract

Background: The results of meta-analysis studies and randomised controlled trials (RCTs) published in the last 10 years were collated and the effect of tea consumption on measures of cardiovascular disease (CVD) was considered. Methods: PubMed was systematically searched for relevant meta-analysis papers and RCTs. Inclusion and exclusion of studies, data extraction, and quality assessment were conducted according to the PRISMA statement. The Jadad criteria was applied to decipher the quality of RCTs. Results: Findings from 19 meta-analysis and 23 randomised controlled trials (n=1,422 participants) were evaluated. Clear evidence was found for blood pressure where 4 to 5 cups of black or green tea daily related to risk reduction. Moderate evidence was of a positive effect of green tea and its associated catechins on total and lowdensity lipoprotein (LDL) reduction. Growing evidence indicates that tea drinking could protect vascular health and reduce inflammation. A wider range of tea forms (chamomile tea, goishi tea, hibiscus tea, sour tea, rooibos tea) are increasingly being studied and also appear to have potentially favourable effects on markers of CVD. Conclusion: Tea drinking appears to play a significant role in blood pressure reduction, particularly amongst those with prehypertension or hypertension. Green tea has beneficial effects on total and LDL cholesterol reduction. Tea drinking in general appears to aid vascular function and the reduction of inflammation. Ongoing long-term trials are needed especially in relation to other tea forms alongside black and green tea.

Black Tea Flavonoids: A Focus on Thearubigins and their Potential Roles in Diet & Health

“…Of the 41 human studies identified, 36 were excluded due to them being review papers (n=13), irrelevant (n=13), laboratory studies (n=6) or a quantitative analysis of TR profiles (n=4) (Figure 3). This with pre/hypertension), vascular function and inflammation [16]. Black tea polyphenols also appear to attenuate obesity and associated comorbidities by: 1) inhibiting saccharide and lipid absorption, digestion and intake, 2) stimulating lipid metabolism and 3) reducing oxidative stress [17].…”