The "Tea Vs Coffee" debate is an ever interesting one with people from southern part of India strongly backing coffee with out which their day does not start! In contrast those from the north, pitch for tea, not because it is better health-wise but for its characteristic flavor. No doubt both Tea and Coffee contain the stimulant Caffeine which makes one more alert and relaxing. That said, the distinction between tea and coffee is getting blurred day by day as India is progressively becoming a national village without any restraining state borders. Efforts of Indian Coffee Board years ago to popularize coffee in the north were some what futile as even to day tea continues to be the dominant beverage in most of the northern states. One of the reasons could be that the taste and flavor of brewed coffee are widely varying, depending on the variety of seed, seed processing method, roasting practice, particle size of the ground coffee and method of brewing. This makes coffee making an extremely adventurous task. As coffee drinking was prevalent in the south for centuries, the art of making good coffee got transferred from generation to generation. In spite of this situation, surprisingly tea gained a firm foot hold in the south during the last 5 decades with many people opting for tea as a change from the coffee drinking routine.
Tea is a historical beverage with its origin attributed to China. There seems to be evidence that tea was a popular drink in both China and India almost 5000 years ago, though its discovery was attributed to Chinese royalty. It was an accidental contamination of hot water with tea leaves and the finding that the tea leaves soaked water was flavorful to the King, led to popularity of tea in China. Its origin in India is shrouded in mystery. Interestingly Chinese discovered that the tea leaves soaked hot water was not only refreshing but also health protective which helped tea to be propagated all over the world. As fresh tea leaves were some what perishable, drying was resorted to reduce moisture and extend its life for some time. Again the observation that bruised tea leaves tended to darken with time and produced aromatic flavors, led to the modern CTD tea technology widely used in the manufacture of black tea. Coincidentally most of the world liked black tea in preference to green tea which led to a thriving tea industry that produces about 2.5 million tons of tea world wide out of which green tea constitutes roughly 20%.
One of the influencing factors that made Chinese population healthier than others might be that they consume green tea regularly in their daily lives and therefore it can be probably considered as their national drink. If that is so what does green tea contain which is not present in black tea? A look back at the massive scientific literature available to day, dwelling on various aspects of tea, will reveal that tea the leaves are a rich source of poly phenols, accounting for about 8-12% of its solid content. These include a number of flavonoids like catechin, epicatechin, epicatechin gallate, epigallocatechin gallate (better known as EGCG) and proanthocyanidinsmost of them with high antioxidant properties. As antioxidants play a vital role in neutralizing oxyradicals in the human body that is considered one of the causative factors in cancer development, tea with its rich antioxidant content is the darling of the health purists world over.
One of the most startling discoveries during the last few years of research on tea poly phenols was that all of them are not equal in conferring health benefits on human beings and the most important component that makes the difference is EGCG which was found to have a significant but specific influence on boosting many enzymes involved in neutralizing oxyradicals at the cellular level and prevent on set of cancers of various types. Unfortunately during the extreme processing conditions involved in converting green tea leaves into black tea, EGCG is converted to theaflavins and thearubigins with no therapeutic properties. Logically therefore green tea beverage will have to be consumed if the benefit of EGCG is desired. The bud and the first leaves of the tea plant contain highest concentration of EGCG and are therefore plucked for making green tea products.
Green tea poly phenols in general were found to increase the biological activity of several enzymes involved in neutralizing the activity of oxyradicals and detoxification and EGCG is the most potent one. The enzyme found to be positively influenced include glutathione reductase, glutathione peroxidase, glutathione S transferase, catalase and quinine reductase in small intestine, liver and lungs. EGCG is considered to have excellent therapeutical significance in preventing and treating a host of disease that include HIV, cancers affecting prostaglandin, brain, cervix and bladder, besides neurodegeneration. Drinking about two cups of green tea a day can confer most of the benefits attributed to EGCG, while consuming 4-6 cups a day is considered a therapeutic dose.
The health supplement industry seems to have got into the EGCG band wagon by putting in the market many products containing this phytochemical though most of them are non-standard ones containing very little or no EGCG at all! In the absence of a regulatory environment these fly by night operators are able to catch the attention of gullible consumers, laughing all the way to their banks! The most blatant use ( or misuse?) of green tea credentials is by the weight reduction products industry which is offering green tea solids containing health supplements based on some studies that a combination of EGCG and caffeine, when consumed, produces thermogenesis in the body leading to depletion of fat, causing some weight reduction. However there is no standardization of these products and the claims are not substantiated by real time studies involving human subjects.
One of the most surprising off shoots of studies using green tea and the EGCG is the finding that sugar spikes that occur after carbohydrate ingestion by diabetic patients can be reduced significantly by consumption of green tea, provided they are consumed together. The scientific logic is that EGCG has an inhibitory effect on starch degrading enzyme alpha amylase which in turn slow down break down of starch into maltose and glucose in vitro. As the ptylin enzyme present in the saliva has also starch digesting ability, the starch hydrolysis which starts immediately after ingestion in the oral cavity itself is retarded. Further exposure in the small intestine to alpha amylase as the food is swallowed and as it travels down the digestive tract, glucose generation is significantly retarded in presence of EGCG. According to recent findings if Egcg and a starchy food are consumed without any gap of time, glucose spike can be slowed down by almost 50% which by itself is remarkable. This finding confers additional benefits on those consuming green tea regularly include insurance against a host of modern day diseases affecting almost all organs in the body. Probably the health food industry will latch on to this discovery and it is a question of time before health supplements containing EGCG or green tea solids are marketed both for targeted consumer groups as well as general population.