There is a record of tea being used as a beverage in China since 2,000 B.C.E. Besides water, it is consumed more than any other drink around the world. The four main types of tea are black, green, white, and oolong.
All four varieties come from the Camellia sinensis plant. Herbal teas are not considered true tea because they do not come from the Camellia sinensis plant.
Oolong tea accounts for only 2 percent of tea consumption around the world. Although less popular, oolong tea still has a variety of benefits. Read on to find out more information about oolong tea and its associated health benefits.
What is oolong tea?
Oolong tea is commonly consumed in China and Taiwan. In Asian countries, drinking tea is a large part of the culture and social gatherings. Friends and business associates often meet over tea.
Although all true tea comes from the same plant, the differences occur in the harvesting and processing. Oolong tea is partially fermented, while black tea is fully fermented.
Tea can also differ in amounts and types of antioxidants. Green tea is high in a class of antioxidants known as catechins. Antioxidants in black tea are theaflavins and thearubigins. Oolong tea falls in the middle, regarding the antioxidant amounts.
Oolong tea and green tea contain similar amounts of caffeine, approximately 10-60 (mg) per 8-ounce cup. For comparison, coffee contains approximately 70 to 130 mg of caffeine per 8-ounce cup.
Unsweetened brewed tea is considered a zero-calorie beverage. It contains no fat, carbs, or protein.
There are a number of health benefits that are thought to derive from drinking oolong tea, as with other types of tea.
Researchers in China studied the relationship between drinking oolong tea and cholestrol levels, as high cholesterol levels can be associated with an increased risk for heart diseases.
They found that people who drank at least 10 ounces of oolong tea per week had lower risks of having high total cholesterol, triglyceride, and LDL or "bad" cholesterol levels. The same was also true of people who drank similar amounts of green and black teas.
People who had been consuming oolong tea for the longest time had lower total cholesterol, triglyceride, and LDL cholesterol levels.
In another study, Japanese men and women were studied for the impact of consuming coffee, green tea, black tea, and oolong tea on their risk of heart disease. Researchers found that men who drank 1 or more cups of oolong tea per day had a lower risk of heart disease.
A study in mice showed that the animals receiving oolong tea extract while being fed a high fat, high sugar diet, gained less abdominal fat than mice on the same diet that did not receive the tea extract.
Green tea and black tea extracts also resulted in less abdominal fat gain. The mice that received the green tea extract also consumed fewer calories.
Researchers in Taiwan examined the association between drinking tea and the risk of head and neck or throat cancer.
Each cup of oolong tea consumed per day equated to a 4 percent lower risk, but the result was not significant. Each cup of green tea consumed per day equated to a 6 percent lower risk for head and neck cancer, which was more significant.
Another study in Chinese women found that drinking green, black, or oolong tea was linked to a decreased risk of ovarian cancer.
However, according to the National Cancer Institute, there is not currently enough research to say for certain that drinking tea decreases cancer risk.
Some studies have shown that drinking 3 or more cups of tea per day is associated with a lower risk of type 2 diabetes.
However, studies specifically looking at oolong tea have had varied results.
In one study, healthy men drank almost 6 cups per day of oolong tea. At different times, they drank oolong tea that contained supplemental antioxidants, which were in the form of catechins or polyphenols. Each of the teas was consumed for 5 days. Researchers found that drinking oolong tea did not improve blood sugar or insulin levels.
Interestingly, one study found that working men who drank 2 or more cups of oolong tea per day had a higher risk of developing diabetes than men who consumed 1 cup of oolong tea per day or no oolong tea.
Fluoride is an element that is often added to drinking water, toothpaste, and mouthwash to help prevent dental cavities.
Tea leaves naturally contain fluoride, so drinking oolong tea could help prevent cavities. Excess fluoride can be harmful, but drinking less than 1 liter of oolong tea per day is safe for most adults.
Other possible benefits:
While there is not enough current research to support the following benefits, drinking tea has also been associated with:
- healthier gut bacteria
- lower risk of Alzheimer's disease
- lower risk of Parkinson's disease
- natural defense from the sun's ultraviolet rays
- stronger bones
Studies that examined long-term consumption of oolong tea showed the greatest results. Although it is not a cure for any condition, drinking tea regularly appears to have numerous health benefits.
Risks and considerations
Although oolong tea contains less caffeine than coffee, people who are sensitive to caffeine should still limit their intake.
Tea can decrease the amount of iron absorbed from plant foods. Also, some researchers found that young children who drank tea were more likely to have lower iron levels.
It may, therefore, be better to drink tea outside of meals to limit its impact on iron absorption. When consumed together at meals, eating foods rich in vitamin C can increase the amount of iron absorbed from plant foods.
Tea is a healthy beverage that has been consumed by people around the world for centuries. Oolong tea is a lesser known variety that may also provide health benefits. However, from some of the research reviewed above, drinking green tea may offer the most health advantages.
Bottled tea contains smaller amounts of beneficial polyphenols and may have excessive amounts of added sugar. If buying bottled teas, it may be better to look for ones that are unsweetened or to brew tea at home and sweeten it with a small amount of honey.
Oolong tea should be steeped for as long as possible to increase flavonoids, and people can consume 2-3 cups per day.