Is black tea effective in reducing the risk of cardiovascular disease in a healthy population?
Date of publication of randomized controlled trial: December 2011
Design
Randomized controlled trial.
Participants
77 healthy participants (age range: 25 to 60 years, 55% males).
Intervention
3 x 200 ml of black tea infusate/day (3 standard cups of 200 ml hot water each containing 3 g of black tea infused for 5 minutes) consumed for 12 weeks without additives (milk or sugar). The tea used contains high levels of gallic acid derivatives (50±0.4 mg/L), flavan-3-ols (42±2 mg/L), flavonols (32±1 mg/L) and theaflavins (90±1 mg/L).
Comparator
Equivalent volume of hot water consumed for the same period.
Major Outcomes
Outcome 1: Change in fasting blood glucose concentration (mg/dL) at week 12;
Outcome 2: Change in triglycerides level (mg/dL) at week 12;
Outcome 3: Change in high density lipoprotein (HDL) cholesterol level (mg/dL) at week 12.
Settings
The trial was conducted in outpatient settings.

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Conclusion
Benefits
Compared to hot water, black tea infusate did not provide significant beneficial effect on fasting blood glucose concentration, triglycerides level and HDL cholesterol level reduction in healthy participants regardless of gender.
Harms
No adverse events were reported in this trial.
Link to Original Article
http://www.ncbi.nlm.nih.gov/pubmed/22198621
Bahorun T, Luximon-Ramma A, Neergheen-Bhujun VS, Gunness TK, Googoolye K, Auger C, Crozier A,Aruoma OI. The effect of black tea on risk factors of cardiovascular disease in a normal population. Prev Med. 2012 May;54 Suppl:S98-102.


* Interpretation of quality assessment results:
• Very low: Further research is most likely to have an important impact on our confidence in this estimate of effect.
• Low: Further research is likely to have an important impact on our confidence in this estimate of effect.
• Moderate: Further research is fairly likely to have an important impact on our confidence in this estimate of effect.
• High: Further research is unlikely to have an important impact on our confidence in this estimate of effect.
• Very high: Further research is most unlikely to have an important impact on our confidence in this estimate of effect.

Details of assessment method can be found at Chung VC, Wu XY, Ziea ET, Ng BF, Wong SY, Wu JC. Assessing internal validity of clinical evidence on effectiveness of CHinese and integrative medicine: Proposed framework for a CHinese and Integrative Medicine Evidence RAting System (CHIMERAS). European Journal of Integrative Medicine. 2015 Aug 31;7(4):332-41.