What is Oolong Tea and What Benefits Does it Have?

Oolong tea represents only 2Percent of the world s tea  but it s well-worth discovering.It combines the qualities of dark and green teas  giving it several interesting health benefits.

For example  it may boost metabolism and reduce stress  helping you feel great each day.This article explains everything you need to know about oolong tea and its health benefits.

What is Oolong Tea?

Oolong tea is a traditional Chinese tea.It s made from the leaves of the Camellia sinensis plant  the same plant used to make green tea and black tea. The difference is in how the tea is processed.

All tea leaves contain certain enzymes  which produce a chemical reaction called oxidation. Oxidation is what turns the green tea leaves into a deep black color. Green tea is not allowed to oxidize much  but black tea is allowed to oxidize until it turns black. Oolong tea is somewhere in between the two  so it is partially oxidized.

This partial oxidation is responsible for oolong tea s color and characteristic taste. However  the color of the leaves can vary between different brands  ranging from green to dark brown.

Nutrients in Oolong Tea

Similar to black and green teas  oolong tea contains several vitamins  minerals and helpful antioxidants.

A cup of brewed tea will contain approximately:

Fluoride: 5–24Percent of the RDI.

Manganese: 26Percent of the RDI.

Potassium: 1Percent of the RDI.

Sodium: 1Percent of the RDI.

Magnesium: 1Percent of the RDI.

Niacin: 1Percent of the RDI.

Caffeine: 36 mg.

Some of the main antioxidants in oolong tea  known as tea polyphenols  are theaflavins  thearubigins and EGCG. These are responsible for many of its health benefits. Oolong tea also contains theanine  an amino acid responsible for the tea s relaxing effect.

Oolong Tea May Help Prevent Diabetes

The polyphenol antioxidants found in tea are thought to help reduce blood sugar and insulin levels. They re also thought to increase insulin sensitivity. Accordingly  several studies report links between regular tea consumption  improved blood sugar control and a lower risk of developing type 2 diabetes.

However  the specific effects of oolong tea are generally not as well researched as those of green or black tea. That being said  a recent review observed that those drinking 24 oz (720 ml) of oolong tea per day had a 16Percent lower risk of developing type 2 diabetes. Another study reported that diabetics who consumed 50 oz (1.5 liters) per day had up to 30Percent lower blood sugar levels at the end of a 30-day study.

Similarly  consuming 33 oz (1 liter) of oolong tea each day for 30 days decreased average blood sugar levels by 3.3Percent. Nevertheless  not all studies agree and one even reports an increased risk of developing diabetes for those drinking 16 oz (480 ml) or more per day. Researchers cite pesticide contamination as a likely cause of the negative effects in this study  and do not recommend avoiding oolong tea because of it.

Oolong Tea May Improve Heart Health

Regularly consuming tea antioxidants may also improve heart health. Several studies of regular tea drinkers report reduced blood pressure and cholesterol levels  as well as a reduced risk of heart disease. In a recent study  people who drank more than 48 oz (1.4 liters) of tea per day were 51Percent less likely to have heart disease  compared to non-tea drinkers.

Several studies have also investigated oolong tea specifically. One study of more than 76 000 Japanese adults observed that those who drank 8 oz (240 ml) or more of oolong tea per day had a 61Percent lower heart disease risk. What s more  a study done in China reports a 39Percent lower risk of stroke in those drinking 16 oz (480 ml) of oolong or green tea per day.

In addition  regularly consuming 4 oz (120 ml) of green or oolong tea per day may reduce your risk of developing high blood pressure by up to 46Percent. However  not all studies agree

One thing to remember is that oolong tea contains caffeine  which may slightly raise blood pressure in some people. That being said  this effect tends to fade with regular caffeine consumption. Furthermore  since the caffeine content in an 8-oz (240-ml) cup is only about one-fourth of that found in the same amount of coffee  this effect is likely to be small.

Oolong Tea May Help You Lose Weight

Scientists believe that some of the polyphenols in oolong tea may boost metabolism and decrease the amount of fat absorbed from your diet. These polyphenol antioxidants are also thought to activate enzymes that help you use stored fat for energy.

One study found that both full-strength and diluted oolong tea helped participants burn 2.9–3.4Percent more total. This could be partially due to the caffeine content of tea  but tea polyphenols may also play a role. To test this idea  researchers compared the effects of caffeine alone to a combination of caffeine and tea polyphenols.

Both increased the amount of calories burned by about 4.8Percent  but only the tea polyphenol and caffeine mix increased the participants fat burning ability.This indicates that the fat burning effects of tea are also caused by the plant compounds in tea  not just the caffeine.

That being said  none of the studies clarified whether this increased energy expenditure and fat burning led to any substantial weight loss in humans. Furthermore  some participants responded better than others  so the effects likely vary from person to person.You can read more in this article about green tea and weight loss. Most of it should apply to oolong tea as well.

Oolong Tea May Improve Brain Function

Recent reviews show that tea may help maintain brain function and prevent Alzheimer s disease. In fact  several components of tea may benefit brain function.

For starters  caffeine can increase the release of norepinephrine and dopamine. These two brain messengers are thought to benefit mood  attention and brain function. Further research shows that theanine  an amino acid in tea  may also help boost attention and relieve anxiety. One recent study reports that tea containing both caffeine and theanine increased alertness and attention within the first 1–2 hours after consumption.

Tea polyphenols are also thought to have a calming effect  especially starting two hours after intake. Few studies have looked specifically at oolong tea  but one found that regular tea drinkers had up to a 64Percent lower risk of brain function decline. This effect was particularly strong for regular black and oolong tea drinkers.

Another study linked regularly drinking green  black or oolong tea to improved cognition  memory  executive function and information processing speed. Although not all studies observed the same beneficial effects of oolong tea on brain function  none were found that showed negative effects.

May Protect Against Certain Cancers

Scientists believe the antioxidants present in black  green and oolong teas may help prevent cell mutations that can lead to cancer in the body. Tea polyphenols might also decrease the rate of cancer cell division.

What s more  one review reports that regular tea drinkers may have a 15Percent lower risk of developing oral cancer. Other reviews report similar protective effects for lung  esophageal  pancreatic  liver and colorectal cancers.

However  most research reports that tea has small or non-existent effects on breast  ovarian and bladder cancers. Additionally  most research in this field focused on the effects of green or black teas  with the biggest effects noted for green teas. Since oolong tea falls midway between green and black tea  similar benefits may be expected. However  more research is needed on oolong tea specifically.

Oolong Tea Promotes Tooth and Bone Strength

The antioxidants found in oolong tea may help keep your teeth and bones strong. One study showed that people who drank black  green or oolong tea daily over a 10-year period had 2Percent higher overall bone mineral density.

A study of 680 postmenopausal Chinese women found that those who drank oolong tea regularly had 4.5–4.9Percent higher bone densities than non-tea-drinkers. In addition  several other recent reviews report similar positive effects of tea on bone mineral density.

A higher bone mineral density could lower the risk of fractures. However  the direct link between oolong tea and fractures has not been investigated yet. Finally  research links tea consumption to reduced dental plaque. Oolong tea is also a rich source of fluoride  which could help strengthen tooth enamel.

Oolong Tea May Help Relieve Eczema

The polyphenols in tea may also help relieve eczema. One study asked 118 patients with severe cases of eczema to drink 33 oz (1 liter) of oolong tea per day  in addition to maintaining their normal treatment.

Eczema symptoms improved as early as 1–2 weeks into the study. After 1 month of the combined treatment  63Percent of patients showed improvement. What s more  the improvement persisted. They were still observed in 54Percent of the patients 5 months later.

Safety and Side Effects

Oolong tea has been consumed for centuries and is generally considered to be safe. That being said  it does contain caffeine. When consumed in excess  caffeine can lead to anxiety  headaches  insomnia  irregular heartbeat and in some  high blood pressure.

Additionally  consuming too many polyphenol antioxidants can make them act as pro-oxidants  which are not good for your health. Excess intake may occur from taking polyphenol supplements  but this is unlikely from simply drinking tea.

The flavonoids in tea can also bind the iron found in plant foods  reducing absorption from the digestive system by 15–67Percent. Those with low iron levels should avoid drinking tea with meals and consider consuming vitamin C-rich foods to help increase iron absorption.

Both the USDA and the European Food Safety Authority (EFSA) consider daily intakes of 400 mg of caffeine as safe. This is equivalent to 48–80 oz of oolong tea (1.4–2.4 liters) per day. Given that the average cup is 8 oz (240 ml)  you could drink a total of 6–10 cups of oolong tea per day without consuming too much caffeine.

However  pregnant women are advised to stick to a maximum of 200 mg of caffeine  which is about 3-5 cups of oolong tea per day. Keep in mind that coffee  soda  energy drinks and chocolate also contain caffeine. So if you re trying to reduce your intake  make sure to account for these sources as well.