BLACK TEA CONSUMPTION LINKED TO PREVENTION OF CHRONIC DISEASE
Consuming one to eight cups of black tea each day is associated with a reduced risk of chronic disease, according to a new research review conducted by Dr Carrie Ruxton on behalf of the Tea Advisory Panel and published in Nutrition & Food Science Journal.
The link between black tea consumption and heart disease risk reduction was particularly strong in this review. However, research studies identified in this study also suggest that black tea might benefit cognitive (brain) function and weight management. This review also suggested that black tea has anti-cancer properties.
Dr Ruxton’s review adds weight to the significant published literature, which associates black tea consumption and reduced chronic disease. Indeed the aim of this review was to update previous work published in 2007 and highlight new research evidence linking black tea with various aspects of health.
Coronary heart disease…
Most of the evidence on black tea is in the field of coronary heart disease (CHD). Dr Ruxton’s review highlighted a considerable body of evidence from observational studies, which found significant associations between regular black tea drinking and various positive outcomes for heart health, such as reduced risk of heart attack, reduced risk of death from CHD and lower blood cholesterol. Consumption of 3 cups of tea each day has been associated with a 11% lower risk of heart attack. A study in more than 26,000 Finnish smokers found that men who drank more than 2 cups of tea a day had a 21% reduced risk of stroke, while a study in more than 6500 French adults showed that women drinking more than 3 cups of tea each day had almost a third less risk of developing fatty plaques in their carotid arteries than non-tea drinkers.
Three recent intervention trials, which looked at the effects of black tea on various factors, associated with heart health. These included triglycerides (a type of blood fat), inflammation and flow mediated dilatation (FMD) which is a measure of blood vessel dilation in response to blood flow. Black tea consumption was associated with significant improvements in these factors. In particular, black tea consumption was found to increase FMD by 3.4%, which could potentially lower heart disease risk.
The health benefits of antioxidant flavonoids…
All in all, this review of studies that have looked at the effect of black tea consumption on heart health shows that black tea appears to reduce CHD risk and to improve markers of CHD risk.
How black tea could produce these benefits is not clear, notes Dr Ruxton. However, among the many substances found in black tea, it could be the antioxidant flavonoids that offer the most plausible explanation. Tea flavonoids could play a role in inflammation, reducing the risk of blood clots, promoting the health of the blood vessels and protecting harmful LDL cholesterol from oxidation, which is when it can do most damage to the arteries.
Dr Ruxton went on to review the potential role of black tea in preventing cancer, highlighting a number of laboratory studies showing how tea and its flavonoids could help to prevent cancer. Some human studies have also shown an association between 2-3 cups of black tea each day and reduced cancer risk, but Dr Ruxton notes that more large studies are required to confirm these findings.
Cognitive Function and Parkinson’s disease…
Going on to look at cognitive function, Dr Ruxton concludes that studies involving black tea in this area are at an early stage. Black tea consumption has been associated with reduced risk of Parkinson’s disease.
In conclusion, Dr Ruxton suggests that studies on heart disease and cancer point to a significant benefit in excess of 2-3 cups of black tea each day. She also notes the concerns that have been expressed regarding the caffeine in tea and its supposed effects on hydration. However, her previous work has indicated that caffeine intakes below 400mg daily are unlikely to have any adverse effects.
She concludes that an optimal amount of black tea consumption is 1 to 8 cups each day (up to 5 to 6 mugs). This amount, Dr Ruxton suggests, would provide enough of the beneficial constituents to increase potential health benefits without exceeding a daily caffeine intake of 400mg.
The Tea Advisory Panel: The Tea Advisory Panel is supported by an unrestricted educational grant from the UK TEA COUNCIL, the trade association for the UK tea industry. The Panel has been created to provide media with impartial information regarding the health benefits of tea. Panel members include nutritionists; dieticians and doctors. For further information please call 0207 7058989 or view all panel biography details by logging on to www.teaadvisorypanel.com.
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