I am not sure what came first: the huge surge in sales and popularity of green tea, or the scientific studies of green tea and health. With oolong taking far less of the tea market, there are far fewer studies on its impact on health, but studies are out there and it's easy to believe there will be more as the scientific field will want to confirm the truth of some of the claims of Oolong, or Wu-Yi tea. Wu-Yi you may know is the infamous diet tea touted by Oprah and others. What have the studies proven so far?
Oolong Tea Health Benefits #1: Antioxidants
Free radicals are linked to many signs of aging, including wrinkles, dark spots and certain diseases, even cancers. They are everywhere - in the air we breathe, the food we eat and even the sunlight. Tea contains antioxidants that mop up the free radicals before they can hurt us.
A 2003 study conducted by Kenichi Yanagimoto compares green tea, oolong tea and black tea for their antioxidant activities.He found green tea to be the most potent antioxidant, followed by oolong tea, then black tea.
Green tea blocked oxidation by almost 100% over 40 days.
Oolong tea blocked oxidation by 50% over 15 days.
Black tea showed only slight antioxidant activities.
Oolong Tea Health Benefits #2: Promote weight loss
Oolong tea has a reputation for weight loss, and rightly so.
Scientific studies have found that it does so by increasing metabolism, burning fat and blocking dietary fat absorption.
There is a lot of hype about what it can do, with some vendors claiming that it can help lose 2 pounds of weight a week. Claims such as this have yet to be proven, but it is true that oolong will increase the metabolism and burn fat. Combine that with some exercise and you've got some serious potential to lose weight and tone your body.
Oolong Tea Health Benefits #3: Promote heart health
Oolong tea is good for the heart in several ways.
A 2007 American study using rats found that oolong reduces blood concentrations of triglycerides (the most common form of fat that exists in the body) by a whopping 80% compared to rats on normal diet.
Another 2001 Japanese study found that it reduces cholesterol after 1 month of regular drinking.
A 2004 Japanese study conducted by Osaka City University found that oolong tea increases plasma adiponectin levels. Low levels of plasma adiponectin are associated with obesity, type 2 diabetes mellitus and coronary artery disease (CAD). The study concluded that oolong tea may have beneficial effects on the progression of atherosclerosis in patients with CAD.
Oolong Tea Health Benefits #4: Treat skin disorders
Atopic dermatitis (AD) skin disease, or eczema, causes the skin to become red, flaky and itchy. Mild forms of eczema can be treated. But many people suffer from what is called the recalcitrant AD, which does not respond to conventional treatment.
Green tea has been known to be anti-allergic. Perhaps drinking oolong tea can help? A 2001 study conducted by Uehara from Shiga University found that drinking oolong tea is good for recalcitrant AD. 118 patients participated in the study. They maintained their dermatological treatment, but also drank 1 litre of oolong tea (made from 10 grams of leaves) a day. Beneficial effects were observed after 1 or 2 weeks. 63% of the patients showed marked to moderate improvements after 1 month.
Oolong Tea Health Benefits #5: Complement diabetes treatment
A 2003 Taiwanese study found that drinking oolong tea is helpful to diabetes patients. 20 patients who had type 2 diabetes and took the prescribed hyperglycemic medicaitons participated in the study. They drank either water or 1.5 litres of oolong tea daily for 30 days. The scientists found that those who drank oolong tea experienced reductions in plasma glucose and fructosamine concentrations by 30% and 20% respectively. Those who drank water experienced no changes. The scientists concluded that oolong tea complements oral agents in the treatment of type 2 diabetes.
Oolong Tea Health Benefits #6: Reduce high blood pressure
A 2004 study by Yang found that drinking green and oolong tea for at least a year reduces high blood pressure. Regular drinkers are 46% less likely to develop high blood pressure if they drink one-half to two-half cups a day. They are 65% less likely to develop high blood pressure if they drink more than 2 cups a day.
Oolong Tea Health Benefits #7: Inhibit bacteria that causes tooth decay
A 1993 study conducted by Nakahara found that oolong tea inhibits the enzyme activities of bacteria streptococci. The bacteria has been known to cause dental plaque to form on teeth, which can lead to dental caries. Nakahara examined green tea, oolong tea and black tea in his study. He concluded that oolong tea extract "exhibits the most prominent inhibitory action among various tea extracts".
Oolong Tea Health Benefits #8: Expectorant
Recent studies suggest that the volatile aromatic vapors from Oolong help dislodge toxic residues from the bronchia and air sacs of the lungs. They can then be expectorated (coughed up and spat out). This effect may help to explain why Chinese men, among the heavier smokers on the planet, tend to have fewer cases of lung cancer.