Gyokuro is a variety of green tea, traditionally grown and harvested in Japan but now available worldwide. The fresh plant has a rich green color, leading to its name, which means "jade dew" in English. The tea variety that produces gyokuro has an especially small leaf, and only the early leaf buds that appear in spring are included in the gyokuro harvest. Green teas such as gyokuro have many health benefits and are useful both as a general health tonic and for treating many different ailments. Discuss gyokuro with your doctor to decide if it might be helpful for your situation.
Gyokuro, like all green teas, is an unfermented tea containing a variety of natural compounds, including flavonoids, polyphenols and proanthocyanidins. Some of these chemicals are potent antioxidants that destroy free radicals, metabolic byproducts or environmental toxins that may damage cellular membranes or DNA. Free radicals contribute to aging and numerous health problems such as heart disease and cancer. Practitioners of traditional Asian medicine use gyokuro to treat many ailments, including heart problems, diabetes and digestive disorders. Modern research indicates that gyokuro has significant health benefits.
One of the polyphenols in gyokuro, epigallocatechin-3-gallate or EGCG, has been studied for its potential to prevent cancer. Memorial Sloan-Kettering Cancer Center summarizes results of a number of laboratory studies showing that green tea extract or purified EGCG protects normal cells from carcinogenic compounds. Clinical and epidemiological studies suggest that green tea may help prevent bladder, breast, ovarian, pancreatic and prostate cancer. In a clinical study published in "Cancer Research" in 2006, 30 men with a precancerous prostate condition who consumed green tea supplements daily for one year developed substantially less cancer than another group who took a placebo. Other clinical studies with human subjects who either had one of several types of cancer or were at risk for the disease produced equally promising results.
Gyokuro and other green teas may lower your risk of heart disease by reducing the buildup of fatty deposits called plaque in your arteries. Components in green tea tend to raise levels of good cholesterol, or high-density lipoprotein, and to lower total cholesterol, decreasing plaque formation. Because it is an antioxidant, gyokuro also lessens oxidation of cholesterol, a necessary step in the production of plaque. Clinical studies summarized by the University of Maryland Medical Center showed that green tea polyphenols also block absorption of cholesterol in your intestines and increase its excretion. All of these properties of gyokuro slow or prevent atherosclerosis and coronary artery disease. According to the University of Maryland experts, drinking three cups of green tea daily lowers your risk of heart attack by 11 percent.
Gyokuro may also lessen your risk for diabetes by keeping your blood glucose in a healthy range, reducing stress on the cells in your pancreas that produce insulin. Green tea may protect the liver from damage caused by toxic substances. EGCG in gyokuro may also help treat hepatitis, a liver inflammation caused by a virus, and may reduce inflammation that accompanies other disorders such as Crohn's disease and colitis. Gyokuro might also help with weight loss, possibly due to enhanced fat burning due to its polyphenols. In a study published in "Obesity Research" in 2005, overweight human subjects who consumed a combination of caffeine and green tea showed improved long-term maintenance of weight loss compared to other groups.
Gyokuro is available from most health food or Asian specialty stores as loose dried leaves or as a supplement in capsules. Although generally considered safe, gyokuro contains caffeine and may cause palpitations, dizziness or insomnia in some people. Do not consume gyokuro if you are pregnant or breastfeeding, and discuss its use with your doctor before adding it to your regimen.
- The Frangrant Leaf: Gyokuro: The Making of Japan's Finest Green Tea
- University of Maryland Medical Center: Green Tea
- Memorial Sloan-Kettering Cancer Center: Green Tea
- "Cancer Research"; Chemoprevention of Human Prostate Cancer by Oral Administrations of Green Tea Catechins in Volunteers With High-Grade Prostate Intraepithelial Neoplasia: A Preliminary Report From a One-Year Proof-of-Principle Study; S. Bettuzzi et al.; January 2006
- "Obesity Research"; Body Weight Loss and Weight Maintenance in Relation to Habitual Caffeine Intake and Green Tea Supplementation; M. Westerterp-Plantenga et al.; July 2005