Theanine Mellows Your Mind, Gives Your Heart a Boost

This compound helps our brains maintain the calm and clarity we need

“I’ve never had a matcha,” my friend’s daughter admitted. “I’m excited to try it!”

For the uninitiated, matcha is green tea in a powdered form.

Documented in China as early as the 8th century but popularized by a Japanese monk in the 12th century, this finely ground green tea powder is traditionally stirred into hot water or milk with a bamboo whisk.

The result is a delicious, if bitter, coffee substitute.

Rich in nutrients

Green tea is rich in polyphenols, B vitamins, minerals (like calcium, magnesium, and potassium), and amino acids.

One of these amino acids is theanine.

Dozens, if not hundreds, of scientific studies have connected theanine to better brain and heart health.

It’s also been linked to longevity.

What is theanine?

Theanine is an amino acid present in all true tea plants and at least one kind of mushroom.

It’s similar in structure to glutamic acid and glutamine, compounds that serve many important functions within the body, including protein synthesis and neurotransmission.

Theanine comes in two forms, L-theanine and D-theanine.

They’re identical in composition, containing the same number of carbon, hydrogen, nitrogen, and oxygen atoms (C₇H₁₄N₂O₃).

They differ in the placement of the OH group (composed of one oxygen atom bonded to one hydrogen atom).

The L form is most common in nature. This is the form that’s biologically available. So when we talk about theanine, we are most often talking about L-theanine.

Theanine is neuroprotective

Theanine has been shown to be neuroprotective.

It’s been shown to reduce excitatory glutamate, delay neuron death, and promote neurogenesis (the creation of new brain cells).

Theanine has been credited with helping to normalize dopamine, serotonin, and GABA signaling disturbances.

GABA signaling is a big issue for anyone suffering from a neurodevelopmental disorder or reduced executive function, according to research done in 2012.

A lifeboat for your brain

Scientists believe that some of the brain effects associated with theanine stem from its resemblance to glutamine, a powerful excitatory neurotransmitter.

Research from 2022 has shown that theanine can occupy glutamate receptors and is able to pass through the blood-brain barrier to exert its relaxation effect.

In a 2021 study, Japanese researchers focused on theanine’s cognitive effects in men and women between the ages of 50 and 69, who are at risk of cognitive decline.

The scientists wanted to distinguish short-term effects from long-term effects, so they measured cognitive functions—attention, working memory, and executive function—after a single dose of theanine (100 mg, about four times the amount found in a cup of green tea), and after daily doses for 12 weeks.

The study was a randomized double-blind, placebo-controlled trial, which means that neither the researchers nor the subjects knew whether they were taking theanine or a placebo.

This is considered the gold standard for obtaining high-quality evidence, although the study did not limit the subjects’ normal intake of tea, which means that the overall intake of both theanine and caffeine was not strictly controlled.

Still, the Japanese researchers found that theanine had a very positive effect on the brain.

“A single dose of L-theanine reduced reaction time in the attention task and increased correct answers and decreased the number of omission errors in the working memory task, which suggests L-theanine may improve working memory and executive function.”

According to another 2021 study, published in the Journal of Neuroscience, when Canadian researchers investigated theanine’s potential to mitigate the negative effects of cannabis on the developing brain, they found that it was neuroprotective.

These scientists fed young rats two doses of theanine daily before injecting them with increasingly higher doses of tetrahydrocannabinol or THC, the most psychoactive ingredient in cannabis.

They found, again, that theanine had a positive effect on the brain.

“The range of neuroprotective effects induced by L-theanine were remarkable not only for their persistence beyond the adolescent THC exposure period, but for the comprehensive nature of its protective effects,” the researchers found.

Drugs intended to increase serotonin levels in the brains of people struggling with depression, SSRIs, have extensive negative side effects.

So, it’s particularly noteworthy that research from the Netherlands has found that theanine increases α–wave activity in the brain, which is indicative of a relaxed state.

All of this research suggests that green tea (including matcha, which is my green tea drink of choice) is an excellent choice of beverages if you’re wanting to improve or safeguard your long-term brain function.

Children with autism benefit from drinking green tea

Some of theanine’s biggest fans are parents of children with autism.

Especially since the COVID lockups, young people across the globe have started suffering from severe anxiety. Children with autism often suffer from higher rates of anxiety than neurotypical youngsters, according to research from Johns Hopkins University School of Medicine.

Motivational speaker and health advocate Terri Hirning says she’s been using theanine for over ten years to help her son who has autism. It even helps him go back to sleep when he wakes during the night.

Is it also good for your heart?

There is also evidence that theanine has beneficial cardiovascular effects.

In one 2012 study, Japanese researchers found that high-stress-response participants (those whose blood pressure tended to rise when facing stress) given 200 milligrams of L-theanine and then asked to perform high-stress tasks not only experienced less anxiety, but also had lower blood-pressure readings than high-stress-response participants who were given a placebo.

Theanine, the researchers concluded, “attenuates the blood-pressure increase in high-stress-response adults.”

Positive synergy with caffeine

In nature, theanine nearly always comes packaged with caffeine.

Theanine is found in the highest concentrations in green tea, especially shade-grown green tea, which has higher levels of both theanine and caffeine.

The two compounds have been shown to have a positive synergy.

In research published in 2016, a team of neuroscientists at Northumbria University in the United Kingdom gave 24 people—12 habitual caffeine consumers and 12 non-consumers—in random order, over four visits:

1) just caffeine

2) just theanine

3) both theanine and caffeine together

4) a placebo

Afterwards, the scientists tested the participants on a range of mental tasks.

The study participants given just caffeine reported fewer headaches and mental fatigue than when they were tested before the dose. They also demonstrated improved reaction time and a better ability to process visual information quickly.

Participants given just theanine reported having more headaches during the testing. Where the people given caffeine had improved scores on the mental math component of the test (counting backward in increments of seven), those given theanine alone did not.

However, the study participants who took the caffeine and theanine together enjoyed all the benefits of caffeine and none of the downsides of theanine alone. They also did better than the caffeine-only group on mental math, as well as on language skills.

So how do you get your daily dose of theanine?

Theanine was originally identified by a Japanese scientist, Yajiro Sakato, who was interested in why gyokuro (shade-grown, rolled-leaf) tea was so rich in umami.

Umami is a Japanese word we don’t really use in English. It describe a deep earthy flavor, like a savory soup.

Sure enough, gyokuro contains abundant amounts of theanine.

However, gyokuro is not always easy to find in the West.

Unlike matcha.

At least in the United States, matcha is trendy these days.

You can buy organic matcha at the grocery store and make your own iced or hot beverage.

Or you can leave it to the experts and buy a matcha at your local coffee shop or tea house.

All caffeinated teas that are made from the leaves of the tea plant, Camellia sinensis, whether black, white, green, oolong, or pu-erh, contain theanine. So drinking any tea will increase your theanine intake.

If you’re not a tea drinker and don’t want to become one, you can get theanine by adding matcha powder to foods and desserts: sprinkle it on fruit salad or ice cream, use it to make a healthy albeit vivid green cake frosting, or whip up a batch of matcha-infused energy balls.

What if you don’t like tea?

Theanine is also present in bay bolete mushrooms, which you can buy fresh at farmers markets or find dried at the grocery store.

The theanine in these mushrooms provides umami flavor and, perhaps, cognitive benefits.

Bay boletes don’t contain any caffeine.

So, to unlock this compound’s full benefits, consider treating yourself to a cup of coffee and some dark chocolate after you eat your ’shrooms.

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Jennifer Margulis is an award-winning science journalist and book author. A different version of this article was originally published in The Epoch Times.