4th International Tea Symposium
Recently I had the privilege of attending the Fourth International Scientific Symposium on Tea and Human Healthheld at the US Department of Agriculture in Washington, DC. The event, sponsored by American Cancer Society, Tea Council of the USA, Linus Pauling Institute, American College of Nutrition, The Vision and Voice of Women in Medicine and American Society for Nutrition, was an exciting meeting of leading institutions and researchers from around the world.
Doctors presented a synopsis of their studies and took questions at the end of their review. Most of the studies reinforced previous findings and focused on green and black tea. Other teas such as oolong and white, also from the plant Camellia sinensis, have similar properties and beneficial effects.
For years researchers have understood that antioxidants work to neutralize free radicals, which may contribute to aging and chronic disease. Tea is one of the best sources of these preventative substances. Tea also contains phytochemicals, naturally occurring plant compounds, which also are thought to play a role in decreasing the risk of cancer and heart disease. Some phytochemicals, such as tea flavonoids and polyphenols, are also antioxidants.
For the most part tea research is based on these and other properties present in tea and the way in which they may counteract the effects of oxidative damage. Slowing down the effects of damaging free radicals, in part, is a choice that we make every day beginning with the food and drinks we put in our bodies. Consuming a diet rich in plant nutrients, fruits, vegetables and tea, is one of the best ways to inhibit aging and combat poor health.
Because of the magnitude of the information shared at the symposium and the overwhelming content presented, I have decided to summarize the information over the next few issues of the newsletter. In this issue I will focus on diabetes, obesity and heart disease.
Researchers spoke about the impact that diabetes is having on our society and how it relates to other chronic conditions. Almost 21 million Americans have diabetes, at least 90% are type 2 diabetes and another 30% of cases are non-diagnosed. They described the alarming spike of diabetes cases since the 1990's, not only in the US but around the globe. Studies have revealed conflicting results when it comes to tea and diabetes. Green tea appears to be the forerunner in reducing blood sugar levels, or increasing insulin activity. Insulin is a protein hormone secreted in the pancreas, which helps the body use sugar and other carbohydrates.
- A USDA study found that insulin activity was increased greater than 15-fold when participants consumed tea. Green, black and oolong teas all had positive results however the greatest activity was elicited by EGCG, found in highest concentrations in green tea.
- Unsweetened tea, up to eight servings a day, is recommended in the Healthy Beverage Guideline because it is virtually calorie free, contains no sugar, has less caffeine than coffee (about 40 mg per serving) and delivers antioxidant benefit.
Researchers also discussed the obesity epidemic and how it impacts disease, declining health and the financial burden it puts on our health care system. Obesity greatly contributes to cardiovascular disease, the number one killer in America, a sizeable portion of which is preventable through diet and exercise.
- One study compared the results of mice that were fed either a low-fat or high-fat diet, with exercise or not, and with or without tea catechins. Mice that ate high fat diets and were given tea catechins showed an 18% reduction in fat accumulation, while exercise alone showed a 14% reduction. Those that exercised and consumed tea catechins reduced fat accumulation by 33%, suggesting that tea catechins may increase fat metabolism allowing the body to burn more fat and storing less.
- A follow up on a previous study of the effects of tea catechins on body fat reduction found that participants that consumed tea with higher concentrations of tea catechins, 690 mg versus 22 mg, over a 12 week period experienced significantly greater reduction in body weight, body mass index and waist size. The tea with higher tea catechins was enhanced with green tea and therefore researchers concluded that consuming 5 cups of strong green tea daily might be useful in preventing and reducing obesity.
The way tea interacts in the body and the mechanisms by which tea flavonoids work requires more in depth investigation but it appears that several mechanisms work in concert collectively improving cardiovascular health, reducing the risk of heart disease and stroke.
- Human studies indicate that people who regularly drink 3+ cups of black tea per day have a reduced risk of heart disease and stroke. Additional clinical trials suggest a reduction in oxidative damage, improved blood vessel and platelet function - all risk factors associated with cardiovascular disease.
- Researchers at the USDA studied the effect of tea on 15 adults with mildly high cholesterol who ate a diet moderately low in fat and cholesterol. Researchers found that participants who consumed 5 or more servings of black tea per day, after 3 weeks, had reduced LDL (bad) cholesterol by 11.1 % and total cholesterol by 6.5 % when compared with a placebo beverage. Additional research is currently being done to confirm these findings.
The symposium was a great exchange of information. Many questions were answered and even more compelling questions were raised. I am hopeful that this forum generates more tea research funding and well thought out studies that include long term human trials.
One researcher summed it up perfectly and it went something like this, "if tea were a new discovery in the Amazon and the research had such positive preliminary findings people would be knocking down doors to get it."
Tea, the age old elixir has not changed and it seems that the beliefs of ancient Chinese scholars is holding true under the scrutiny of present day scientific research. Tea, without all of the additives and sugar, is beneficial in warding off disease, aiding metal focus and soothing the soul.