A new study from UC Irvine revealed that green and black tea have the ability to reduce blood pressure. Compounds in both types of tea help relax blood vessels by activating ion channel proteins in the vessels’ walls. The findings provide more insight into how tea benefits health and may result in better blood pressure medications.
The discovery came from the laboratory of Geoffrey Abbott, Ph.D., a Department of Physiology and Biophysics professor at UC Irvine. A graduate student in the Abbott Lab, Kaitlyn Redford was the first author of the study. The findings were published in Cellular Physiology and Biochemistry.
The study revealed that green and black tea have two catechin-type flavonoid compounds (epicatechin gallate and epigallocatechin-3-gallate). Both of these compounds activate a certain ion channel protein called KCNQ5. This causes potassium ions to disperse out of cells, which lowers cellular excitability.
The smooth muscle inside blood vessels contains KCNQ5, which becomes activated by catechins in green and black tea. Researchers, including collaborators at the University of Copenhagen, believed this could also relax blood vessels.
Dr. Abbott said this:
“We found by using computer modeling and mutagenesis studies that specific catechins bind to the foot of the voltage sensor, which is the part of KCNQ5 that allows the channel to open in response to cellular excitation. This binding allows the channel to open much more easily and earlier in the cellular excitation process.”
Around one-third of the global adult population suffers from high blood pressure. However, health experts consider hypertension as the most modifiable risk factor for cardiovascular disease and early death. New findings and research about ways to treat hypertension could have huge implications for public health.
Previous studies have confirmed that green and black tea can lower blood pressure by a minimal but consistent amount. Researchers believe that the catechins present in tea play the largest role in lowering blood pressure.
How catechins in green or black tea activate KCNQ5 channels
Researchers have identified KCNQ5 as the main ion channel protein affected by tea catechins. They believe this discovery will result in more advanced medicinal chemistry optimization in the future.
KCNQ5 helps control the vascular tone as well as regulate electrical activity and neuron signaling in the brain. When these neurons become impaired due to genetic variants, it can lead to epileptic encephalopathy. This debilitating developmental disorder causes frequent seizures due to malfunctions in the ion channel.
However, the discovery of green and black tea’s ability to activate KCNQ5 may lead to new treatments for seizures. Since catechins have the ability to cross the blood-brain barrier, researchers believe this could help cure brain excitability disorders.
People all over the world have consumed tea for over 4,000 years due to its health benefits. Each day, people drink about 2 billion cups of tea globally, second only to water in regard to volume consumed. The three most popular caffeinated teas include green, oolong, and black.
Each of these tea varieties comes from the leaves of the evergreen species Camellia sinensis. The differences in the color and flavor of the teas come from varying fermentation processes during production.
How you “take” your tea makes a difference, according to the study
Many people in countries such as the United States and the UK prepare black tea with milk. Interestingly, researchers found that milk prevented the tea from activating KCNQ5 when they directly applied it to cells. When people drink tea with milk, though, it shouldn’t have the same effect.
However, according to Abbott, “We don’t believe this means one needs to avoid milk when drinking tea to take advantage of the beneficial properties of tea. We are confident that the environment in the human stomach will separate the catechins from the proteins and other molecules in milk that would otherwise block catechins’ beneficial effects.”
The team came to this conclusion due to other studies showing antihypertensive benefits of tea, whether consumed with milk or not. Using mass spectrometry, the team also found that warming green tea to 35 degrees Celsius altered its chemical composition. When warmed to this temperature, the tea became more effective at activating KCNQ5. However, researchers say that you can get the same benefits by drinking the tea hot or cold. Abbott explains:
“Regardless of whether tea is consumed iced or hot, this temperature is achieved after tea is drunk, as human body temperature is about 37 degrees Celsius. Thus, simply by drinking tea we activate its beneficial, antihypertensive properties.”
Because green and black tea can help lower blood pressure, researchers hope that new treatments will become available. Perhaps medications will include tea catechins in the future, or doctors will prescribe drinking tea as a viable solution.
Other benefits of consuming green or black tea
Here are some great reasons to take tea every day.
Green tea benefits
- Lowers blood sugar
- Improves digestion
- Reduces free radicals
- Lowers cancer risk
- Reduces cholesterol
- Decreases risk of heart and liver disease
- Improves liver health
- Increases cognitive function
- It helps prevent colds and cases of flu
- Boosts immune system
Black tea benefits
- Increases alertness and energy
- Boosts metabolism
- Improves cardiovascular health
- High antioxidant content, including polyphenols and catechins
- Lowers diabetes risk
- Reduces cancer risk
- Lowers stroke risk
- Improves bone health
- Anti-inflammatory properties
While green and black tea both have caffeine, an amino acid in tea called L-theanine helps counteract it. It helps increase your concentration and alertness while producing a calming effect, unlike coffee. If you’ve been trying to give up your coffee addiction, consider drinking tea in the morning instead. It contains all the same benefits as coffee without overstimulation.
Final Thoughts: Study reveals drinking green or black tea can lower blood pressure
A new study shows that drinking green or black tea can help reduce blood pressure by acting on KCNQ5 channels. When these ions become activated, they cause blood vessels to dilate, therefore lowering blood pressure. Besides, green and black tea have been proven to have many other health benefits. Lowering cancer risk, improving cognitive function, and reducing inflammation are just a few notable benefits.
If you don’t already drink tea, consider having 1-2 cups per day. Not only will it improve your health, but it just may help you kick your coffee habit!
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