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Oolong tea

The word Oolong comes from the Chinese word "Wu Long", which means black dragon. In the old tradition, the tea leaves were curled or twisted during production so that they later looked like small black dragons in the finished product. The original home of oolong tea is the province of Fujian (Fukien) in China. Today, oolongs are also produced in Guangdong and on the island of Taiwan. Oolong teas have also been popular in Japan and South East Asian countries for many years and are becoming increasingly popular. Due to its fine aroma and flavor, it is also becoming increasingly popular in America and Europe.

The best-known oolong teas

As mentioned above, the Chinese province of Fujian is famous as the region of origin of oolong teas, and emigrants brought the technique of oolong production to Taiwan. There, the knowledge and art of production was cultivated and perfected. Tung Ting Oolong and Pouchong Oolong, for example, have become very famous as a result. Differences in the medicinal properties, taste and aroma of Chinese and Taiwanese oolongs can simply be traced back to differences in soil conditions and production methods. In mainland China, the tea has more "body" and is fuller in flavor because it is generally exposed to longer fermentation times (oxidation). In Taiwan, people prefer more fragrant, lighter varieties.

Health aspects

Oolong tea is a highly prized and valuable drink due to its medicinal properties. The infusion is naturally mild and has a soft cup. Consumed regularly over a longer period of time, it is said to reduce fat. Clinical tests in China and Japan have not only shown the mild antiseptic effect on the digestive organs, but have also confirmed a blood pressure-lowering effect in cases of high blood pressure, support and promotion of blood circulation, and a detoxifying and draining property. Oolong tea has long been praised on the market as a slimming and beauty-promoting health drink. In America and Europe, scientific research results are still pending, but empirical observation suggests that oolong tea does indeed have a number of health-promoting properties.

Polyphenols in partially fermented tea lower blood sugar levels

Chinese oolong tea can lower blood sugar when drunk regularly. This was confirmed in 20 outpatient type 2 diabetics who were taking antidiabetic medication. In addition, they drank either 1.5 liters of oolong tea or the same amount of water every day for 30 days. The groups and drinks were then swapped, so each patient tested both drinks (cross-over design). The blood glucose levels of the tea drinkers dropped significantly from an average of 229 mg/dl to 162 mg/dl, while there was no change in the water drinkers. There were no side effects.

Safety and side effects

Too much oolong tea - more than 4 cups per day - can cause side effects due to the caffeine content. These side effects can range from mild to serious and include headaches, nervousness, sleep problems, vomiting, diarrhea, irritability, irregular heartbeat, tremors, heartburn, dizziness tinnitus, convulsions and confusion.

Precautions and warnings

Pregnancy and breastfeeding: Oolong tea may not be harmful to pregnant and breastfeeding women in small amounts. However, pregnant and breastfeeding women should not drink more than 2 cups of oolong tea per day. This amount of tea provides about 200 mg of caffeine. Consuming more than 2 cups of oolong tea may not be safe and harmless. Too much caffeine during pregnancy could cause premature birth, low birth weight and harm the baby. Too much caffeine during breastfeeding can cause irritability and more frequent bowel movements in breastfed children.

Children: Caffeine is probably safe and harmless for children at normal dietary levels.

Anxiety disorders: The caffeine in oolong tea may exacerbate anxiety disorders.

Blood clotting disorders: Some research suggests that caffeine may slow blood clotting. Although this research has not been done with humans, there are concerns that caffeine could worsen blood clotting disorders.

Heart disease: The caffeine in oolong tea could cause irregular heartbeat.

Diabetes: Some research suggests that the caffeine in oolong tea may affect the way diabetics process sugar and make it more difficult to control blood sugar. There is also interesting research suggesting that caffeine may increase the warning signals of low blood sugar levels in people suffering from type 1 diabetes. This could help diabetics to recognize and treat low blood sugar levels. One drawback, however, is that caffeine could increase the incidence of hypoglycemia. For these reasons, diabetics should talk to their doctor before using oolong tea.

Diarrhea: The caffeine in oolong tea can aggravate diarrhea, especially in large quantities.

Irritable bowel syndrome: In addition to diarrhea, the caffeine contained in oolong tea can also aggravate the symptoms of irritable bowel syndrome, especially in large quantities.

Glaucoma: The consumption of oolong tea can increase intraocular pressure. This increase begins within 30 minutes and lasts for at least 90 minutes.

High blood pressure: The caffeine contained in oolong tea may increase blood pressure in people with high blood pressure. However, this effect may be weaker in people who regularly drink oolong tea or other caffeinated products.

Osteoporosis: The consumption of oolong tea can increase the amount of calcium excreted in the urine. This could weaken the bones. If you suffer from osteoporosis, you should therefore limit your caffeine intake to less than 300 mg per day (about 2 to 3 cups of oolong tea). Taking calcium supplements could help to compensate for calcium loss. If you have a genetic disorder that affects the way your body processes vitamin D, you should consult your doctor before consuming large amounts of caffeine.

Interactions

Oolong tea should not be taken in combination with the following medications:

Amphetamines

Stimulants such as amphetamines accelerate the function of the nervous system. By accelerating the function of the nervous system, stimulants can cause a feeling of inner restlessness and speed up the heartbeat. The caffeine contained in oolong tea could also accelerate the function of the nervous system. Consuming oolong tea in combination with stimulants could cause serious problems including accelerated heart rate and high blood pressure. For this reason, oolong tea should not be consumed in combination with stimulants.

Cocaine

Stimulants such as cocaine accelerate the function of the nervous system. By accelerating the function of the nervous system, stimulants can cause a feeling of inner restlessness and speed up the heartbeat. The caffeine contained in oolong tea could also accelerate the function of the nervous system. Consuming oolong tea in combination with stimulants could cause serious problems including accelerated heart rate and high blood pressure. For this reason, oolong tea should not be consumed in combination with stimulants.

Ephedrine

Stimulants accelerate the functioning of the nervous system. The caffeine and ephedrine contained in oolong tea are both stimulants. Consuming oolong tea in combination with ephedrine can cause excessive stimulation and sometimes serious side effects and heart problems. For this reason, oolong and ephedrine should not be consumed at the same time.

Adenosine

The caffeine contained in oolong tea may block the effects of adenosine. Adenosine is often used by doctors to perform a test of the heart called a cardiac stress test. Due to the possible interactions, you should stop drinking oolong tea and other caffeinated products at least 24 hours before such a test.

Antibiotics (quinolone antibiotics)

The body breaks down the caffeine contained in oolong tea in order to be able to excrete it. Some antibiotics can reduce the rate at which the body breaks down caffeine. Taking these antibiotics in combination with caffeine can increase the risk of caffeine side effects including shakiness, headaches, increased heart rate and more.

Cimetidine

The body breaks down the caffeine contained in oolong tea in order to excrete it. Cimetidine can reduce the rate at which the body breaks down caffeine. Taking cimetidine in combination with oolong tea may increase the risk of caffeine side effects including shakiness, headaches, increased heart rate and others.

Clozapine

The body breaks down clozapine in order to excrete it. The caffeine contained in oolong tea appears to reduce the rate at which the body breaks down clozapine. Consuming oolong tea in combination with clozapine could increase the effects and side effects of clozapine.

Dipyridamole

The caffeine contained in oolong tea could block the effects of dipyridamole. Dipyridamole is often used by doctors to perform a test of the heart called a cardiac stress test. Due to the possible interactions, you should stop drinking oolong tea and other caffeinated products at least 24 hours before such a test.

Oestrogens

The body breaks down the caffeine contained in oolong tea in order to excrete it. Estrogen can reduce the rate at which the body breaks down caffeine. Taking estrogen in combination with caffeine could cause shakiness, headaches, rapid heartbeat and other side effects. For this reason, you should limit your caffeine intake if you are taking estrogens.

Fluvoxamine

The body breaks down the caffeine contained in oolong tea in order to be able to excrete it. Fluvoxamine can reduce the rate at which the body breaks down caffeine. Taking fluvoxamine in combination with oolong tea can increase the effects and side effects of caffeine.

Lithium

The caffeine contained in oolong tea can increase the rate at which the body excretes lithium. If you consume products that contain caffeine and are taking lithium, you should slowly reduce your intake of caffeine-containing products. Stopping caffeine intake too quickly can increase the side effects of lithium.

Medication for depression ( Monoamine Oxidase Inhibitors / MAOI)

Oolong tea contains caffeine. Caffeine can stimulate the body. Some medications used for depression can also stimulate the body. The consumption of oolong tea in combination with these medications could result in excessive stimulation. This could cause serious side effects including rapid heartbeat, high blood pressure, nervousness and more.

Medications that slow down blood clotting

Oolong tea could slow down blood clotting. The consumption of oolong tea in combination with medications that also slow down blood clotting could increase the risk of bleeding and the tendency to bruise.

Some medications that can slow blood clotting include aspirin, diclofenac (Voltaren), ibuprofen, naproxen and others.

Nicotine

Stimulants such as nicotine accelerate the function of the nervous system. By accelerating the function of the nervous system, stimulants can cause a feeling of inner restlessness and speed up the heartbeat. The caffeine contained in oolong tea could also accelerate the function of the nervous system. Consuming oolong tea in combination with stimulants could cause serious problems including accelerated heart rate and high blood pressure. For this reason, oolong tea should not be consumed in combination with stimulants.

Phenylpropanolamine

The caffeine contained in oolong tea can stimulate the body. Phenylpropanolamine can also stimulate the body. Consuming oolong tea in combination with phenylpropanolamine could result in excessive stimulation and increase the heart rate, raise blood pressure and cause nervousness.

Riluzole

The body breaks down riluzole in order to be able to excrete it. The consumption of oolong tea can reduce the rate at which the body breaks down riluzole and thus increase the effects and side effects of riluzole.

Theophylline

Oolong tea contains caffeine. Caffeine works in a similar way to theophylline. In addition, caffeine can reduce the rate at which the body breaks down theophylline. Consuming oolong tea in conjunction with taking theophylline may increase the effects and side effects of theophylline.

Alcohol

The body breaks down the caffeine contained in oolong tea in order to be able to excrete it. Alcohol can reduce the rate at which the body breaks down caffeine. Consuming alcohol with oolong tea can increase the risk of caffeine side effects including shakiness, headaches, increased heart rate and more.

Birth control pill

The body breaks down the caffeine contained in oolong tea in order to excrete it. The contraceptive pill can reduce the rate at which the body breaks down caffeine. The consumption of oolong tea in combination with the contraceptive pill can cause shakiness, headaches, rapid heartbeat and other side effects.

Fluconazole

The body breaks down the caffeine contained in oolong tea in order to be able to excrete it. Fluconazole can reduce the rate at which the body breaks down caffeine. Taking fluconazole in combination with oolong tea may increase the risk of caffeine side effects including shakiness, headaches, increased heart rate and others.

Diabetes medication

Oolong tea contains caffeine. Caffeine may increase blood sugar levels. Diabetes medication is used to lower blood sugar levels. By increasing blood sugar levels, oolong tea could reduce the effectiveness of diabetes medication. For this reason, blood sugar levels should be carefully monitored. It is possible that the dosage of diabetes medication may need to be adjusted.

Mexiletine

The body breaks down the caffeine contained in oolong tea in order to be able to excrete it. Mexiletine can reduce the rate at which the body breaks down caffeine. Taking mexiletine in combination with oolong tea can increase the risk of caffeine side effects including shakiness, headaches, increased heart rate and others.

Terbinafine

The body breaks down the caffeine contained in oolong tea in order to excrete it. Terbinafine can reduce the rate at which the body breaks down caffeine. Taking terbinafine in combination with oolong tea may increase the risk of caffeine side effects including shakiness, headaches, increased heart rate and others.

References

  1. Komatsu T, Nakamori M, Komatsu K, Hosoda K, Okamura M, Toyama K, Ishikura Y, Sakai T, Kunii D, Yamamoto S. Oolong tea increases energy metabolism in Japanese females. J Med Invest. 2003 Aug;50(3-4):170-5.
  2. Rumpler W, Seale J, Clevidence B, Judd J, Wiley E, Yamamoto S, Komatsu T, Sawaki T, Ishikura Y, Hosoda K. Oolong tea increases metabolic rate and fat oxidation in men. J Nutr. 2001 Nov;131(11):2848-52.
  3. Hosoda K, Wang MF, Liao ML, Chuang CK, Iha M, Clevidence B, Yamamoto S. Antihyperglycemic effect of oolong tea in type 2 diabetes. Diabetes Care. 2003 Jun;26(6):1714-8.
  4. Ooshima T, Minami T, Aono W, Tamura Y, Hamada S. Reduction of dental plaque deposition in humans by oolong tea extract. Caries Res. 1994;28(3):146-9.