DRINKING four to five cups of tea a day lowers blood pressure and reduces the risk of a heart attack or stroke, new research reveals.
People with high blood pressure are the most likely to benefit and there is evidence that drinking as few as three cups a day can cut systolic (the top number) and diastolic (the bottom number) blood pressure by two to three points.
Cardiovascular disease kills 150,000 people a year in the UK and accounts for 26 per cent of all deaths. Dr Tim Bond, lead author of the new study and a member of the Tea Advisory Panel (TAP) says: “Given the huge burden of heart and vascular disease in the UK, even a modest reduction in risk could save thousands of lives.”
Previous research shows that lowering systolic blood pressure by 5 mmHg reduces the risk of a heart attack, stroke or fatal cardiovascular event by 13 per cent, and a reduction of just 2mmHg in diastolic pressure cuts the likelihood by 12 per cent.
Authors of the latest study found regular consumption of black or green tea not only reduces blood pressure, it also lowers cholesterol, improves cardiovascular function and damps down inflammation — which can be a contributing factor in heart disease and other serious health problems.
Their findings, which have just been published in Journal of Nutrition & Food Sciences, are based on a review of data from 23 randomised controlled trials and 19 meta-analysis papers.
Co-author, Dr Chris Etheridge from TAP, says: “There has been a large body of anecdotal and observational evidence suggesting tea protects against heart disease, but our review of the latest studies and trials confirms there is a clear benefit.
“We know there are a number of lifestyle interventions such as weight loss, improved diet and increased activity which will help reduce the risk of heart disease or a stroke, but the reality is that a large percentage of the population is not adopting these strategies.
“The beauty of turning to tea to help reduce risk is that it is easy, appealing and infinitely achievable.”
Key findings of the research, commissioned by TAP are:
- Drinking two cups of black tea for just eight days significantly reduces both systolic and diastolic blood pressure and stopped blood pressure going up after eating fatty food.
- Three cups a day for six months reduces both blood pressure readings by 2 to 3 mmHg and lowers overnight blood pressure by 10%.
- Regular consumption of black and green tea delivers reductions in blood pressure at a population level.
- People with raised blood pressure and long-term tea drinkers are the most likely to benefit from a brew.
- Both black and green tea significantly reduce levels of the LDL cholesterol associated with cardiovascular risk.
- Tea has been shown to lower blood levels of LDL cholesterol, with those at highest risk seeing the greatest reduction.
- A 12-week study found three cups of black tea lowered levels of dangerous triglycerides by 35.8% and the ratio of unhealthy LDL cholesterol to protective HDL cholesterol improved by 16.6%.
- Drinking tea with breakfast prevents a spike in triglyceride levels over the next three hours.
- Green tea appears to have the most potent cholesterol lowering power, delivering significant reductions in both LDL and total cholesterol levels.
- Drinking black tea twice a day raised levels of circulating angiogenic cells, which play an important role in the formation, repair and regulation of blood vessels. It also improves blood flow by increasing flow-mediated dilation.
- Two cups of tea a black day improves blood flow and reduces arterial stiffness.
- Drinking one to three cups of green tea a day reduces the risk of stroke by 36% and the odds of having a heart attack by 19%.
- One cup of green tea a day lowers the risk of dying of cardiovascular disease by 5%.
- After drinking three cups of black tea a day for 12 weeks Type 2 diabetics, who are at increased risk of heart disease, had increased levels of the regulatory T-cells which prevent auto-immune disease and lower levels of inflammatory cells.
- C-reactive protein, which is a marker for inflammation, was cut by 53.4% in men and 41.1% in women at high risk of heart disease who drank three cups of black tea a day for 12 weeks.
Dr Emma Derbyshire, a public nutritionist and one of the study co-authors, says: “The evidence is overwhelming. Drinking tea every day helps protect against heart disease and stroke. Most of these benefits seem to flow from the high levels of polyphenols in both black and green tea, but the nation’s favourite brew also contains other protective and health-enhancing compounds including theaflavins, thearubigins and tannins.
“Drinking more tea is a simple step towards reducing cardiovascular disease which could help save lives and NHS resources.”
The authors calculate that a reduction of just one per cent in cardiovascular events would save the health service more than £30million a year.
Dr Tim Bond adds: “Millions of us enjoy tea every day, but now there is even more reason to put the kettle on.”