Tea Please!

Recent research on the benefits of green tea.

Comsumer Bulletin

Written By:
WholeFoods Magazine Staff
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Civilizations from around the world have been enjoying tea for the past 5,000 years or more. Teas aren’t just soothing beverages, though. Several varieties also boast a therapeutic side to them. Green tea, for example, has been known to have several health benefits, many of which have been the topic of much research in recent years alone. Though this tea is widely consumed as a beverage, you can also find green tea extract as a standalone supplement or in combination formulas (1). Read further as we highlight some of the latest research behind what this herb has to offer from a health standpoint.

High Time for Green Tea
Diabetes. Green tea may help diabetics because it can regulate serum glucose levels in the body. So, exactly how can green tea offer this benefit? It inhibits both salivary and intestinal amylase, thereby causing starch to be broken down slower and minimizing the rise in serum glucose levels. Green tea may also heighten the body’s sensitivity to insulin, which might lower one’s risk for diabetes (2).

A Japanese retrospective cohort study of 17,413 participants (6,727 men and 10,686 women, ages 40 to 65, with no prior history of type 2 diabetes) was implemented, along with a five-year follow-up questionnaire. Study findings were based on consumption of coffee as well as black, green and oolong teas (the three main tea types). During the five-year assessment, some 444 new cases of diabetes developed in 231 men and 213 women. Green tea, along with the aforementioned caffeinated beverages, was associated with a 33% deflated risk of diabetes (3).

Oral health. Did you know that green tea can be an important factor in maintaining oral health? It’s true. Green tea’s impact on the reduction of periodontal disease symptoms may be a result of the antioxidants, catechins. Catechins can reduce gum inflammation, where periodontal bacteria live and breed.

A study published in the Journal of Periodontology unearthed the finding that green tea is beneficial for healthy teeth and gums. During the trial, 940 male participants (ages 49 to 59) were evaluated based on three factors of periodontal disease: periodontal pocket depth (PD), clinical attachment loss (CAL) of gum tissue and bleeding on probing (BOP) of the gum tissue (4). Clinicians noted that for every one cup of green tea taken each day, there was a decrease in all three indicators, which shows a link between a lowered risk of periodontal disease and regular green tea consumption. In addition, the researchers found that green tea may help combat gum disease because of its high concentration of polyphenols, which are antioxidant compounds that may help protect from free radical damage.

Weight loss.
Though researchers are hard at work finding exactly how green tea aids in weight loss, they believe it speeds the rate at which fat is broken down in the body (1). A study printed in the February issue of the Journal of Nutrition, shows that belly flab may be alleviated with the help of green tea.

Researchers evaluated 132 obese men and women. Each consumed a diet with the same amounts of daily calories and everyone participated in moderate exercise for 180 minutes a week. Individuals also drank a beverage each day containing 39 milligrams of caffeine, but one of the groups consumed green tea with 625 milligrams of catechins (5). After a 12-week period, the participants drinking green tea lost more body weight than the control group. The green tea group also saw greater declines in total abdominal fat, subcutaneous abdominal fat and triglycerides.

With that, a study completed at the University of Geneva, Switzerland showed that an antioxidant in green tea, epigallocatechin gallate (EGCG, which only is found in green tea), stimulates the body’s ability to burn calories and fat. In fact, the study suggests that a daily dose of 270 mg EGCG caused men to burn a total of 4% more energy than normal (1).

Bone strength.
A growing body of evidence shows that green tea may safeguard against bone loss, as well. An article published in the Journal of Agricultural and Food Chemistry, presented by researcher Ping Chung Leung and colleagues from the Chinese University of Hong Kong, cites the link between green tea and bone growth.

For several days, scientists exposed bone-forming cells (osteoblasts) to three major components of green tea: epigallocatechin (EGC), gallocatechin (GC) and gallocatechin gallate (GCG). Of note, researchers suggested that EGC boosted the activity of a crucial enzyme, which can promote bone growth by as much as 79%. EGC also drastically inflated levels of bone mineralization that were found in cells, which is known to strengthen bones. Last, clinicians said that high concentrations of ECG blocked the activity of osteoclasts, which are responsible for bone resorption (6). WF

References
1. H. Iso, et al., “The Relationship between Green Tea and Total Caffeine Intake and Risk for Self-Reported Type 2 Diabetes among Japanese Adults,” Annals Int. Med. 144 (8), 554–562 (2006).
2. Greentealovers.com, http://greentealovers.com/greenteahealthotherconditions.htm, accessed October 22, 2009.
3. K.S. Stote and S.J. Baer, “Tea Consumption May Improve Biomarkers of Insulin Sensitivity and Risk Factors for Diabetes,” J. Nutr. 138, 1584S–1588S (2008).
4. M. Kushiyama, et al., “Relationship Between Intake of Green Tea and Periodontal Disease,” J. Periodonol. 80 (3), 372–377 (2009).
5. S. Roan, “Green Tea Plus Exercise Speeds the Loss of Tummy Fat,” Los Angeles Times, http://latimesblogs.latimes.com/booster_shots/2009/01/green-tea-plus.html, accessed October 22, 2009.
6. C.H. Ko, et al., “Effects of Tea Catechins, Epigallocatechin, Gallocatechin, and Gallocatechin Gallate, on Bone Metabolism,” J. Agricult. Food Chem. 57 (16), 7293 (2009).

Published in WholeFoods Magazine, Dec. 2009