Tea is derived from a particular plant (Camellia sinensis) and includes only four varieties: green, black, white, and oolog. The more processing the leaves of the plant undergo, the darker they will turn.  Regardless of the processing method, brewed tea not only tastes good, but can have many health benefits as well, ranging from prevention of diabetes to boost brain functions.

Interestingly, a new research corroborated that populations which drink high quantities of black tea have a significantly lower prevalence of diabetes. The study, which was published in British Medical Journal (BMJ), assessed the black tea consumption rates of 42 different countries and analysed them against each country’s rates of respiratory, infectious and cardiovascular disease, as well as cancer and diabetes.

The team reported a linear correlation between the quantity of black tea consumed and the incidence of diabetes across the 42 nations. In addition, they found the population that consumes double the amount of black tea to another has about one quarter less cases of diabetes.

The global prevalence of type 2 diabetes has increased six-fold over the past few decades. The International Diabetes Federation calculates that the number of those with the disease will soar from 285 million in 2010 to 438 million in 2030.

For the study, the researchers systematically mined information on black (fermented) tea consumption in 50 countries across every continent, based on 2009 sales data collected by Euromonitor (World Tea Consumption Survey).

Using data from the World Health Survey conducted by the World Health Organisation, the team then assessed tea consumption against rates of cancer, diabetes, and respiratory, infectious and cardiovascular disease.

No doubt, the fact that populations which drink lots of black tea suffer less cases of diabetes is an interesting finding, and one which the researchers said they intend to further work on to further understand the driving factors behind this exciting research.

Interestingly, green tea, because it can dull the spikes in blood sugar associated with starchy food consumption is also important in diabetes control.

In a finding, published in Molecular Nutrition and Food Research, a chemical substance present in green tea (epigallocatechin-3-gallate or EGCG) can help to reduce blood sugar spikes in mice fed a high starch diet.

The research team found mice fed EGCG had significant reductions of blood sugar spikes after a starchy food when compared to mice that were not fed the compound. Interestingly, the spike in blood glucose level is about 50 per cent lower than the increase in the blood glucose level of mice that were not fed EGCG.

For humans, they suggested that this may mean that green tea could help control the typical blood sugar increases that are brought on when people eat starchy foods, like breads and bagels that are often a part of typical breakfasts.

Drinking green tea, like black tea is also beneficial to boost the quality of sperm. A new study by Italian researchers said low doses of a chemical compound (epigallocatechin gallate or EGCG) which is present in green tea improved measures of sperm quality, including motility. This chemical compound is a water-extractable substance.

The researchers, in the journal, Molecular Nutrition and Food Research, exposed human sperm samples to a range of concentrations of EGCG. Results showed that, at low concentrations, EGCG was associated with increased sperm motility, viability, and phosphorylation of proteins controlling cell survival.

Green tea contains between 30 and 40 per cent of water-extractable polyphenols, while black tea (green tea that has been oxidized by fermentation) contains between three and 10 per cent. Oolong tea is semi-fermented tea and is somewhere between green and black tea. The four primary polyphenols found in fresh tea leaves are epigallocatechin gallate (EGCG), epigallocatechin, epicatechin gallate, and epicatechin.

Sub-fertility in men is reported to account for between 25 and 30 per cent of all infertility cases, and is listed as one of the many reasons that birth rates are falling in many countries of the world. In addition, about 50 per cent of male fertility is the result of unknown causes (idiopathic), and nutrition has been touted as a potential way of boosting the quality of sperm.

Drinking green tea also influences brain function and boost working memory. According to the first study ever to use functional neuroimaging methods to observe changes in the brain following the consumption of green tea extracts, drinking green tea was found to affect parts of the brain linked to working memory.

The study, published in the European Journal of Clinical Nutrition, adds to the long list of potential health benefits of green tea and its extracts, including reducing the risk of Alzheimer’s and certain cancers, improving heart and oral health, as well as aiding in weight management.

The researchers recruited 12 healthy volunteers and asked them to perform a working memory task after consuming 250 or 500     ml of a whey-based soft drink with or without green tea extract (Rivella AG, Switzerland) in a double-blind, controlled repeated measures within-subject trial.

Moreover, long term consumption of green tea could help to slash the risk of gastrointestinal cancers by over a quarter. According to new research in Chinese women, published in the American Journal of Clinical Nutrition, women who drank green tea for prolonged periods of time had a lower incidence of developing certain digestive system cancers, especially cancers of the stomach, oesophagus and colorectum.

For all digestive system cancers combined, the risk was reduced by 27 per cent among women who had been drinking tea regularly for at least 20 years, suggesting that long-term cumulative exposure may be particularly important. The women drink green tea more than three times per week for more than six months.

Specifically, those who consumed about two to three cups per day (at least 150 grams of tea per month) had a 21 per cent reduced risk of digestive system cancers.

Though most studies have focused on the better-known green and black teas, white and oolong also bring benefits to the table. Tea can boost exercise endurance. Scientists have found that the catechins (antioxidants) in green tea extract increase the body’s ability to burn fat as fuel, which accounts for improved muscle endurance. In fact, green tea is the best food source of catechins.

Drinking tea could help reduce the risk of heart attack and hydrate the body. The antioxidants in tea might help protect against many cancers, including breast, colorectal, lung, colon, skin, oesophagus, stomach, small intestine, pancreas, liver and prostate.

 Tea is high in oxygen radical absorbance capacity. It helps to destroy free radicals (which can damage DNA) in the body. While our bodies are designed to fight free radicals linked to cancer, heart disease and brain degeneration, on their own, they’re not 100 percent effective.

 Regular tea drinking might also counteract some of the negative effects of smoking and might even lessen the risk of lung cancer. Green tea has been found to improve bone mineral density and strength.

Tea’s health benefits are largely due to its high content of flavonoids — plant-derived compounds that are antioxidants. Green tea is the best food source of a group called catechins. In test tubes, catechins are more powerful than vitamins C and E in halting oxidative damage to cells and appear to have other disease-fighting properties. Studies have found an association between consuming green tea and a reduced risk for several cancers, including, skin, breast, lung, colon, oesophageal, and bladder.

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