Challenges in Elucidating the Benefits of Drinking Green Tea

Tea is drunk all over the world because it is believed to be a healthy drink. While there is a growing body of research supporting the benefits of drinking green tea, there are significant challenges to prove it as well. As tea leaves are harvested, they are immediately steamed, producing green tea. If it is processed even further, black and white tea are produced. As green tea is the most unprocessed form of all the varieties of tea, it is said to contain the most abundant amounts of catechins, producing a myriad of health benefits.

One of the benefits of drinking green tea is its supposed action to protect the body from cancer. Green tea has been linked to prevent lung, colon, pancreatic, breast and kidney cancer. As catechins have potent antioxidant activity, they protect the cells from potential damage stemming from oxidative stress.

Green tea is traditionally used for diabetes. Animal studies have shown that green tea significantly reduces the blood sugar levels in rats. In humans, patients receiving green tea supplements have lower hemoglobin A1C, which is a marker of adequate glucose control. EGCG, a catechin found in green tea, seems to mimic the activity of insulin, a hormone that increases the utilization and storage of glucose. EGCG also blocks the body’s process of producing glucose from fatty tissues in between meals.

Dieters also enjoy the benefits of drinking green tea as green tea enhances metabolism. It is hypothesized that catechins inhibit the activity of catechol-O-methyl transferase, favoring thermogenesis, a process that is directly linked to increased utilization of fats. A study has shown that participants receiving a combination of green tea and caffeine demonstrated significant weight loss and decreased body mass index.

Green tea is also thought to protect from atherosclerosis, a disease wherein the arteries are blocked. It is especially dangerous if the blockage occurs in the arteries of the heart or brain, resulting in a heart attack or stroke. It is believed that green tea lowers total cholesterol and LDL (the “bad” fat), which is a major risk factor for developing atherosclerosis.

The consumption of green tea may seem to be beneficial in a number of ways. However, skeptics say that real-world evidence is still lacking as the most consistent findings on the benefits of drinking green tea are from animal studies. For example, human studies on the anti-cancer properties of green tea have yielded conflicting or inconclusive results. Furthermore, those that do demonstrate beneficial effects were conducted on populations in Asia where tea is a mainstay in the diet. It can also be assumed that a diet rich in fish or soy may have influenced the outcomes of these studies. As of now, the scientific literature is bereft of large-scale trials that clearly demonstrate the benefits of green tea.

There is still the unanswered question of how much green tea is enough to reap the benefits of drinking green tea. EGCG is not a stable compound and is easily metabolized by the body to inactive forms. Thus, it is not readily available for the body to use. It is also uncertain whether synthetic catechins in supplements will have the same activity as the catechins someone will get by actually drinking green tea. Huo et al stated that a number of issues like stability, bioavailability and metabolism of the drug must be overcome before catechins can be developed to full-fledged therapeutic agents. Most experts still recommend that green tea be consumed only to complement a healthy, balanced diet, not as a drug to cure or prevent something.