The first studies concerning the benefits of green tea were more like surveys. Researchers noted the dietary habits of different groups of people from around the world. They found several paradoxes that they could not explain with the knowledge that they had, at the time.

You have probably read that a high intake of dietary fat contributes to heart disease, high cholesterol and, of course, obesity. Everyone knows that smoking is bad for your health. Smokers have an increased risk of lung, stomach and throat cancer, as well as heart disease. Knowing all of this, when researchers looked at the dietary and lifestyle habits of the Japanese, French and other cultures, there were some things that they could not explain.

Among Japanese smokers, for example, they saw a lower than expected incidence of stomach cancer, throat cancer and heart disease. They also found that the smokers drank large amounts of green tea (a liter or more) every day. When these results were released, news reports said that the benefits of green tea drinking ?may? include the prevention of heart disease and cancer.

So, we started to see supplements containing green tea extract, mainly for those of us that don't like the beverage or prefer to avoid the caffeine. A liter could contain 200mg of caffeine or more, depending on the plant's age and where it was grown. Indian teas, for example, typically have more caffeine than those grown in China.

Another paradox was found among the French. Researchers saw a lower than expected incidence of heart disease, despite a diet that is high in saturated fat. The connection that they established there was to an antioxidant found in some types of red wine, which is often used for cooking and for drinking. You may have seen supplements containing resveratrol, because of this link.

You see, over the years, there have been numerous studies concerning naturally occurring substances (antioxidants, anti-inflammatories, antifungal, etc) found in plants and other sources that provide benefit to a person's health, but to take any one of these nutrients alone is not likely to provide the desired benefit. You will get more of the benefits of green tea extract, if a supplement manufacturer took the time to do the research required to determine which nutrients work together and what dosage is appropriate.

The precaution that consumers need to take when drinking the beverage has to do with the caffeine content. Too much caffeine causes nervousness, anxiety, insomnia and other health problems.

When it comes to supplements, the product should include no more than 100mg of the extracts. Some studies indicate that the extracts can be toxic to the liver at high dosages. You can get the benefits of green tea extract, safely, as long as you choose the right supplement.