Drinking 3 or more cups of tea a day can help play a role in warding off heart disease and may also boost brain function, a major new scientific investigation has found.
A large-scale independent review of published studies and research on the potential health-benefits effects of tea, commissioned by the Tea Advisory Panel (TAP), discovered drinking black tea (regular tea with or without milk) can help play a part in helping to tackle chronic health conditions.
In the literature study, leading independent dietician and member of the Tea Advisory Panel, Dr Carrie Ruxton, reviewed existing scientific literature on black tea – which is the same as regular tea. The results are to be published in the June issue of the journal Nutrition and Food Science.
Dr Ruxton’s analysis revealed that drinking three to four cups of tea a day – about the same as two mugs – significantly cuts the risk of a heart attack, keeps hydration at a healthy, optimal level, and improves alertness and mood. Tea also appeared to have anti-cancer properties.
Clinical studies reveal that natural plant antioxidants found in tea, called polyphenols, have beneficial effects on many biochemical processes in the body via a range of mechanisms, including antioxidant and anti-inflammatory actions. Dr Ruxton’s study shows clearly that drinking tea can reduce the risk of a having a heart attack. It also concludes that adding milk doesn’t change the effectiveness of the polyphenols.
Flavonoids are a class of plant metabolites from the polyphenol group that are thought to be especially useful, with a number of research papers reporting a link between flavonoid intake and a decreased risk of heart attack. There are also emerging data which suggest that a high intake of flavonoids could aid weight control or support cognitive function.
TAP’s research review by author and member, Dr Ruxton covered three main areas. Summaries of the findings are below.
Coronary heart disease and stroke
The link between coronary heart disease (CHD) and tea has been the subject of a relatively large number of studies. Analysis of these indicates that drinking at least three cups of tea a day can lower the risk of a heart attack by 11 per cent – and up to 70 per cent in two studies. A study in Finland found that men who drank more than two cups of tea a day had a 21 per cent reduced risk of stroke, and similar French research found that women who drank more than three cups of tea a day had a 32 per cent lower risk of developing blocked arteries.
A review of 23 published studies on the impact of caffeine on cognitive function found positive effects on mood, alertness and mental performance, and research suggests flavonoids may help promote blood flow around the brain. In addition, a Finnish study discovered that drinking at least three cups of tea daily could significantly reduce the risk of developing the chronic neurological condition, Parkinson’s disease. Tea drinking was linked with better cognitive function, according to a large-scale Chinese research survey, while another study found that drinking four cups of tea a day could help tackle stress.
Dr Ruxton found relatively few published studies investigating the potential of flavonoids in tea to help combat human cancer – in part because carrying out studies on cancer is limited by the timescale of cancer development, the many different sites at which cancer occurs in the body and the myriad of causes. However, one study found that tea could help inhibit cancer tumour growth and help kill off cancer cells. Further studies found that drinking at least two cups of tea a day reduces the risk of endometrial and skin cancers, while drinking three cups reduces the risk of renal cancer by 15 per cent. However, as Dr Ruxton explains, more research is needed to explore tea’s anti-cancer potential.
Report author and TAP member Dr Ruxton says: “Tea is a national favourite but, as well as being a delicious and refreshing drink; it also has some great health benefits thanks to its high flavonoid content. My research showed that there’s a very solid – and growing – body of evidence that indicates tea can play an important role in helping to combat cardiovascular problems such as heart disease and stroke. We’re not sure of the exact mechanism, but it’s thought that tea flavonoids could be involved in controlling inflammation, reducing thrombosis (excess blood clotting), promoting blood vessel function and helping to limit furring up of the arteries.
“In addition, my study showed that tea may be a useful addition to an anti-cancer diet. However, much more research should be done to establish a definite link with cancer prevention, and to pinpoint why tea might be having an effect. However, this area of research is very exciting for the future. We also found solid evidence of tea helping to boost cognitive function and reduce stress, probably related to tea’s modest caffeine content. Some interesting research on the role of tea flavonoids in helping to combat certain neurological conditions is emerging.”
Dr Ruxton adds: “There’s no doubt that the natural ingredients in tea offer significant health benefits. My research shows that you don’t need to drink gallons of tea to get real improvements – just three or four cups of tea a day are enough.”
TAP member Dr Catherine Hood says: “The scientific community is learning more and more about tea and its health properties. Studies show that there are some very powerful ingredients in tea that can play a hugely important role in protecting the body from some serious and potentially fatal conditions. A cuppa is a great way to relax or unwind but could also give your health a crucial boost. Just a few cups a day have shown to help – and drinking more isn’t a problem either as up to eight cups a day have been shown to be fine.”
Black tea is the most consumed drink after water with 131,150 tons of tea consumed in the UK in 2006/07. The 2001 National Diet and Nutrition Survey reported that 77 per cent of British adults drink black tea with a mean intake of 2.3 mugs (540ml) per day. Tea drinking is more popular among older consumers and females according to the National Drinks Survey.
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The Tea Advisory Panel:
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Notes to editors:
Dr Carrie Ruxton is a member of the Independent Tea Advisory Panel
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