We British do seem to have an insatiable appetite for foreign cuisine, and one country whose traditional fare seems to have made a successful migration to these shores is Japan. While taste and fashion are likely to be driving forces in the rising popularity of Japanese food in these parts, my suspicion is that another contributory factor has been its healthy reputation. It is often said that the fish-rich nature of sushi and sashimi gives these foods disease-protective and life-extending properties. However, another Far East foodstuff that may help to explain the relative good health and longevity of the Japanese is green tea. Research has linked an increased consumption of this oriental infusion with a reduced risk of conditions such as cancer and heart disease. It seems there is good reason to consider green tea as much more than merely the flavour of the month.
Researchers seeking an explanation for green tea’s apparent health-giving qualities believe they have found it in the form of substances known as polyphenols. These constituents of the tea plant have what is known as ‘antioxidant’ activity, which means they have the potential to quell disease-promoting molecules known as free radicals. While green tea contains several polyphenols, research suggests that the most potent weapon in its armoury is likely to be a compound known as epigallocatechin gallate (EGCG). EGCG has been found to have a number of cancer-protective actions in the body, including an ability to help in the deactivation of cancer-causing chemicals (carcinogens).
The supping of green tea has been linked with a reduced risk of cancer in both men and women. In one recent study, women drinking the equivalent of about half a cup of green tea a day were found to have a 47 per cent reduced risk of breast cancer compared to those drinking none at all. In another study published earlier this year, researchers found that men consuming three cups of green tea each day had about a quarter of the risk of prostate cancer compared to non-green tea drinkers. Other research has found that increased green tea consumption appears to protect against other forms of cancer too, including those of the stomach, colon, lung and skin.
The apparent liquid assets of green tea seem to extend to benefits for the circulatory system too. Research has found that individuals who consume green tea tend to have lower blood levels of cholesterol. A study published in the Journal of Nutrition last year found that the drinking of green tea was associated with a significant lowering of blood pressure levels. These benefits go at least some way to explaining research which links green tea consumption with a reduced risk of stroke and heart disease.
While consumption of this big-in-Japan beverage is on the rise in the UK, we mostly elect to drink tea in its black form – itself made by subjecting green tea to a process of fermentation. The fermentation of green tea causes the chemical conversion of much of its EGCG into compounds that seem to offer more muted benefits for the body. While studies show that that black tea has the potential to benefit health, the research suggests that it’s green tea that deserves the cup.