Oolong Tea Raises Metabolism Supporting Health Goals

Teatime is an honored tradition in Great Britain and much of Asia, and tea plays an important role in cultures around the world. Teatime in the West often focuses on the food served with the beverage, while in Eastern cultures, serving tea has been elevated to an art form. It’s an ancient beverage that has demonstrated dramatic and positive effects on health.

Tea is one of the most popular beverages served around the world, second only to water. Nearly 80% of all U.S. households have tea in the kitchen cabinets and it's the only beverage commonly served hot or cold. In the U.S., 84% of the tea consumed is black tea, 15% is green tea and the remaining 1% is split between oolong, white and pu’erh.

The popularity of this wildly healthy tea is not any greater around the world as it accounts for just 2% of tea consumption worldwide. Although some say oolong is a black tea, and others a green tea, it does not fall into either category.

There are four varieties of tea produced from the Camellia sinensis plant: black, white, green and oolong. Although called tea, herbal teas are not true teas as they do not originate from the Camellia sinensis. One of the benefits oolong shares with green tea is its ability to change the rate of your metabolism.

Oolong Tea May Boost Your Metabolism and Weight Loss Efforts

Scientists have been intrigued by what they found to be weight regulating chemicals in tea, identified as catechins, which are commonly found in green and oolong varieties. The two most interesting have been epigallocatechin gallate (EGCG) and theaflavins.¹

Researchers recently reviewed tea data in the hope of identifying functional foods affecting energy metabolism that may be used as a complementary dietary strategy in weight management.

In their review of oolong studies, they found that oolong tea had an effect on the modulation of energy balance, fat and carbohydrate metabolism. It also affected activity in the liver, fat, muscle and pancreatic cells after ingestion due to its high levels of EGCG and theaflavins.

The catechins appeared to inhibit the development of fat by down-regulating gene expression and stimulating energy consumption in the mitochondria. Another noted mechanism was an enhanced noradrenaline-induced fat breakdown after drinking oolong tea water extract.

The researchers theorized this effect could be partially due to the caffeine and other bioactive compounds found in the tea. In one animal study included in the review, researchers found ethanol extract of oolong tea triggered weight loss in mice.

Oolong May Boost Insulin Sensitivity

During their review of the literature² researchers identified increased insulin activity after consuming oolong tea, in addition to reduced plasma glucose, which had a positive effect on diabetic rats. They believe the tea could be an effective adjunct in the treatment of Type 2 diabetes.

They found research supporting the combination therapy of oral antihyperglycemic medications and oolong tea, which was more effective at lowering blood glucose than using medications alone. Improved insulin utilization may reduce the risk of metabolic syndrome and Type 2 diabetes, both of which can assist with weight control.

The results of the literature review were similar to a study published in the Journal of Nutrition,³ in which researchers evaluated the energy expenditure of 12 men. The researchers designed a randomized crossover study to compare 24 hours of calorie-burning after the participants underwent one of four interventions.

For four days prior to the study, volunteers did not drink any beverages with caffeine or flavonoids. The participants took each treatment for three consecutive days, and on the third day, their energy expenditure was measured. They either drank water, full-strength tea, half strength tea or water that contained 270 mg of caffeine.

The results demonstrated that energy expenditure was increased by 2.9% for those drinking full-strength tea and 3.4% for those who consumed caffeinated water, as compared to those who drank just water.

An additional 281 calories were burned by those drinking full-strength tea and an extra 331 calories were burned by those drinking caffeinated water. The researchers also measured fat oxidation, which was significantly higher in those who drank the full-strength tea as compared to those drinking water.

Look for Tea, Not Weight Loss Tea

Just as there’s a difference between herbal tea and true tea from the Camellia sinensis plant, products sold as “weight loss teas” usually contain more than you bargain for. Actress Jameela Jamil started a campaign to warn men and women that these types of products may lead to dehydration and diarrhea. As Insider writes:⁴

“It turns out the heart-healthy teas that you might actually want to drink, which are scientifically-linked with good health outcomes, are both cheaper than a “teatox” detox tea and much safer for your body in the long run.”

Detox teas contain more ingredients than black or green tea leaves and their producers make claims that consuming the beverages will detoxify your body. These campaigns are targeted toward those who want to lose weight.⁵ Beginning September 18, 2019, Instagram started blocking ads for weight loss products aimed at users younger than 18 years of age. They also blocked ads that promised miraculous fixes for issues related to body image.

Although tea is healthy, too much of a good thing is not usually a better thing. Tea from the Camellia sinensis plant contains oxalates, which may contribute to the formation of kidney stones and other kidney conditions.

Oolong Produced Differently Than Black or Green Tea

While oolong is neither black nor green, the flavor and characteristics of the tea may fall closer to the black tea or green tea range depending on how it was processed. During processing, the leaves are oxidized between the level of green tea, which keeps much of the original color and flavor, and black tea, which is fully oxidized.⁶

This may be described as partial oxidation or partial fermentation.⁷ However, depending on the tea master, oxidation can vary from 8% to 80%, which explains the variation in flavors. Oolong tea leaves are also traditionally rolled, curled or twisted to alter the appearance, color, and aroma of the final product.

Black, green and oolong tea begin the processing journey in the same way. The leaves are first bruised and then allowed to wither, beginning the oxidation process. They are laid out to dry in the sun for several hours and then removed and cooled away from the heat.

Once fully cool, the leaves destined to become oolong tea are rolled and bruised to break down the cell walls. The leaves continue oxidation until the tea master is satisfied with the process and then are roasted to stop fermentation.

Once fully dried they are sorted according to size and color. Just as the color and flavor fall between green and black tea, so does the caffeine content. If the tea leaves were lightly oxidized, they'll have a lower level of caffeine, but higher levels of oxidation increase measurable caffeine.

Long-Term Health Benefits of Oolong Tea

Researchers have long studied the benefits of coffee and tea on neurological, vision, bone and metabolic health. Different types of tea offer different benefits, many of which are tied to the processing method used to manufacture the tea.

One of the benefits of oolong being oxidized slightly more than green tea and slightly less than black tea is that this specific level offers some of the benefits of both, making it one of the healthiest types of tea you can drink. The tea is rich in polyphenol antioxidants, which your body uses to fight the damage triggered by reactive oxygen species and free radicals.

Drinking green tea is associated with a reduced risk of all-cause mortality, lowered blood pressure and reduced chronic inflammation. The EGCG is responsible for helping your arteries relax and improve blood flow.

Drinking a cup each day may do more than boost your metabolic rate. It can go a long way toward improving your overall health and well-being. Oolong tea has also demonstrated the ability to lower the risk of brain function decline. The tea is rich in theanine, which is believed to help improve attention and relieve anxiety.

The antioxidants in oolong tea may reduce your risk of heart disease if you drink 8 ounces or more every day. In one study researchers found that those who drank 16 ounces of green tea or oolong tea daily experienced a 39% reduced risk of stroke.

How to Store and Brew Oolong for the Best Flavor

While oolong is healthy, it is important to use loose tea leaves. Tea bags may be more convenient, but many are made with heat-resistant polypropylene to prevent the bag from breaking apart in hot water. This means minute pieces of plastic likely end up in your drink.

Paper tea bags are treated with epichlorohydrin, a chemical to prevent tears, which has been found to be a probable human carcinogen. Epichlorohydrin reacts with water to form 3-MCPD, another possible human carcinogen.

The fermentation process extends the shelf life of the tea, with heavily oxidized varieties lasting as long as two years. Loose-leaf oolong tea tends to quickly become stale, so it's important to store it properly.

The tea should be placed in an airtight container and kept in a dry, dark cabinet away from direct sunlight and heat. If stored close to spices and coffee the tea may pick up their flavors and odors.

Variation, oxidation and processing techniques mean a difference in the ideal brewing temperature. Look for the directions on the packaging for brewing instructions. Here are a few general tips to consider.⁸

• Use fresh, pure filtered water. Do not use distilled water as it will give your tea a flat flavor.
• In general, the tea should be steeped between 180 degrees and 200 degrees Fahrenheit for one to three minutes.
• Oolong teas can be steeped multiple times. With each cup the leaves unfurl just a little more, releasing more flavor. You may be able to get up to five infusions out of high-quality tea.
• Oolong tea tastes best with a short infusion so it's a good idea to taste it after the recommended time before deciding to steep it longer.
• Cover the tea while it steeps to keep all the heat in the vessel, and try drinking it without any additives such as milk or sugar, to improve the health benefits and appreciate the handcrafted flavor of the tea.

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