Potent antioxidants - catechins - are present in copious amounts in the leaves of Camellia sinensis, a tea plant. This antioxidant is also present in various other foods like apples, berries, chocolate and red wine, but in much smaller quantities. Scientists have been studying the health benefits offered by catechins since the 1990s, mainly because in many cultures across the globe the benefits of drinking tea have been associated with health and long life.
The type of catechins present in the tea plant leaves is also called catechin polyphenols. They all belong to a molecular family known as flavonoids. Precisely speaking, flavonoids are secondary metabolites of plants. In other words, flavonoids are not necessary for the plants' growth, but vital for them to remain in good health.
Scientific studies have proved that catechins are not only beneficial for the plants' health, but also for the health of humans. In vitro experiments have revealed that the catechins found in tea leaves possess the aptitude to slow down the growth of carcinogenic cells in the human body. Aside from this, these antioxidants can also put off the activity of the detrimental free radicals, which are responsible for cell damages that may result in cancer.
However, it is unfortunate that the findings of studies undertaken to find the health benefits of catechins for humans are yet to be conclusive. Findings of a number of studies have shown that people who drink tea regularly face less chances of developing particular cancer forms. On the other hand, there are some studies that did not show any health benefit of drinking tea. In other words, it is difficult to conclude the extent to which the antioxidants present in tea are beneficial to humans.
For instance, a major study involving 18,000 Chinese men showed that men who consumed tea often faced 50 percent less risk of stomach cancer than men who did not drink tea too often. Then again, another study undertaken in the Netherlands and involving about 120,000 men and women examined the relation between drinking tea and the incidences of stomach cancer. Unfortunately, the findings of this study did not show any evidence that drinking tea helped to prevent stomach cancer.
It has been found during the course of several studies that the amount of catechins present in green tea is more compared to those in black tea. While all varieties of tea, both green and black tea, are prepared following the same initial processes, the leaves of black tea get enough time to ferment as well as oxidize. As a result, it is believed that the additional process used for preparing black tea actually lessens the quantity of antioxidants. Hence, the leaves of green tea are a much better source of antioxidants.
The above explanation is one of several describing the differences between green tea and black tea and also the findings of the studies undertaken in China and the Netherlands. While green tea is a part of the diet in China, it is not used as widely in the remaining regions of the globe. This probably suggests that people in the Netherlands perhaps consumed black tea containing comparatively lesser catechins. Therefore, it is possible that the tea they consumed offered less protection against cancer.
The Davis-based University of California suggests that in all there are five different varieties of catechins, but the chemical structure of all are same. This common chemical structure makes them stabilize the free radicals. Free radicals are unstable molecules that are created as offshoot of the usual digestive process or whenever one is exposed to toxins present in the environment, for instance smoking cigarettes or harmful industrial chemicals. In addition, they can also form on one's eyes or skin when they are exposed to the ultra-violet (UV) rays of the sun. It is worth mentioning here that free radicals have the potential to harm various parts of human cells, counting the cellular membranes and DNA. In due course, free radicals may accumulate inside the body, thereby speeding up the aging process. At the same time, free radical build-up may also increase one's chances of developing cancer and other ailments that may be potentially serious.
Catechins can be described as polyphenols that occur naturally in some plant foods such as green tea, black tea, chocolate, red wine and others. Apparently, they have positive effects on our health, as they seem to forage the harmful free radicals and, at the same time, normalize the functioning of DNA inside the cells. Catechins have a number of mechanisms, but scientists are yet to comprehend them fully.
Several studies have found that green tea is a very good source of catechins. Green tea that is processed commercially is usually heated using steam or pan fried. These two processes actually help to augment the concentration of catechins in the tea leaves by means of stimulating the oxidative enzymes that are sensitive to heat. As far as weight of catechins in tea leaves is concerned, their concentration in green tea is between 30 to 40 percent. On the other hand, the weight of catechins in black tea is just about 10 percent.
Several in vitro studies undertaken on animals time and again suggested that catechins possess the ability to prevent and, in specific incidences, also reverse anomalous cell growths. However, there is some good news and that all these results have been found to be extremely vigorous. These results were repeated in dissimilar situations with dissimilar animals as well as with different conditions. Every time the results were the same. On the other hand, the quantity of catechins taken orally by the subjects of the studies was generally much more compared to what is found in a standard diet. Moreover, the mechanism by which these antioxidants promoted cellular health even when taken in much lower doses is yet to be ascertained. In fact, this would be a good reason why you should take catechin supplements prepared from green tea. Findings of epidemiological studies related to consumption of green tea have been more varied compared to animal studies undertaken in laboratories (in vivo).
Apparently, catechins work to lower the oxidative stress in our body. However, scientists are yet to fully comprehend why this happens. Initially, they believed that catechins present in green tea forage the detrimental free radicals. However, now it appears that its notion is too simplified. Now, it seems that polyphenols stimulate specific enzymes in our cells that trigger a chain of redox reactions, which is believed to alter the oxidative stress of the cells.
It has been found that catechins present in green tea influence lipid as well as carbohydrate metabolism favourably. In addition, green tea extract also facilitates the assimilation of cholesterol and triglycerides. Findings of several studies have shown that people who drink green tea have a tendency to expel additional fatty acids through their urine compared to people who don't drink green tea. Some studies have also demonstrated that catechins present in green tea also help to lessen plasma cholesterol and reduce LDL (low density lipoprotein or "bad") cholesterol, while increasing the levels of HDL (high density lipoprotein or "good") cholesterol in our blood. Nevertheless, some studies also found that these effects only occur when catechins are ingested in extremely high doses. This makes it difficult to assume the health benefits of consuming green tea.
As far as scavenging the alkyl peroxyl radical is concerned, several studies have found that catechins are ten times more effective compared to vitamin C and even beta-carotene. Findings of one particular study showed that polyphenols present in green tea are actually more powerful antioxidants compared to rosemary extract, vitamin C and vitamin E. In fact, in a number of systems, these antioxidants are more potent compared to curcumin.
Catechins get rid of free radicals, thereby preventing development of certain forms of cancer. They block the growth of substances that cause cancers. They are also effective in inhibiting the aging process, by eliminating the harmful free radicals. Catechins are also beneficial for people with high blood cholesterol levels. These antioxidants bind with cholesterol, sop up and block it. Catechins prevent bad or LDL cholesterol formed in the blood stream as a result of oxidation, thereby preventing the constriction of blood vessels. Build-up of LDL (low density lipoprotein) cholesterol is responsible for contraction of the blood vessels.
Among the several health benefits of catechins, these antioxidants help to put off development of heart attacks, arterial sclerosis, brain strokes and thrombosis. They are also effective in lowering high blood pressure. Catechins also prevent diabetes by blocking the activity of enzymes that digest as well as assimilate sugar.
These antioxidants also help to improve the health of our intestines, as they stop the growth of harmful bacteria, while promoting the growth of beneficial bacteria, such as bifid bacteria. Consequently, catechins are effective in regulating the functioning of the intestines. They also prevent bad odour in the body by connecting to various ingested foods like fish, meat and others. In addition, they also connect with breath and human waste.
Catechins help to detoxify the body by means of binding with noxious substances and the detrimental heavy metals (for instance mercury, lead, cadmium, chrome and others) inside the body and dissolve them. They also possess the ability to convert the destructive ultra-violet (UV) rays into non-damaging light, thereby protecting the plants.
It is believed that when one gargles with green tea, they are able to protect them effectively from influenza, as green tea possesses anti-viral properties.