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, my suspicion is that another factor has been its healthy reputation. It is often said that the fish-rich nature of sushi and sashimi gives these foods disease-protecting and life-extending properties.
However, another Far Eastern 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.
Researchers seeking an explanation for green tea's apparent health-giving qualities believe they have found it in the form of 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 de-activation of cancer-causing chemicals (carcinogens).
Drinking green tea has been linked with a reduced risk of cancer in both men and women. In one study, women drinking 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.
Added to this, those who drink 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, which goes some way to explaining research which links green tea 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 drink black tea - 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. While studies show that black tea has the potential to benefit health, the research suggests that it's green tea that deserves the cup.