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There Are Plenty Of Reasons To Be Skeptical About L-Theanine

Tiger Woods’ mental toughness is legendary. Indeed, the world’s best known golfer’s success is often ascribed to a combination of superb athletic talent, hard work and an amazing ability to focus under stressful conditions. Tiger’s clutch performances are almost uncanny. Could he be getting some sort of chemical help? Oh, don’t get all nervous now. Nobody is accusing Tiger of using illegal drugs. But the man does admit to dosing himself with L-theanine. And he even recommends it to others. In fact, in 2007, Woods was the front man for “Gatorade Tiger Focus,” a beverage that “includes L-theanine which, combined with carbohydrates and advanced hydration, helps promote mental focus.”

“I’ve experienced a lot of amazing moments in my golf career, but Gatorade Tiger is taking me someplace I never imagined with this campaign. I’m really excited about how this launch has come together because it brings to life that I’m always thinking about taking my game to the next level.” Frankly I don’t quite understand what Tiger meant by that, or where this version of Gatorade took him, except perhaps to the bank at an increased frequency. 

Others also hope to capitalize on theanine. “Slow Cow” is a novel beverage that aims to take Red Bull by the horns and wrestle the energy drink to the ground with claims of increasing mental awareness and relaxation without sleepiness. So is there any science here? A smidgen. 

Early research into theanine can be traced to the “tea paradox.” How is it that tea, with its significant caffeine content, has a reputation as a calming beverage? Why is a “cuppa” the traditional British answer to stress? Such questions aroused scientific curiosity. Could there be some component in tea that mitigates the effects of caffeine, researchers wondered? And then in 1950, a Japanese laboratory turned up a candidate in theanine, one of hundreds of compounds found in that extract of the leaves of the Camellia sinensis plant which we call tea. It was of interest because of its close chemical resemblance to two of the brain’s most important neurotransmitters, glutamic acid and gamma-aminobutyric acid (GABA). Since drugs that increase the available amount of GABA in the brain typically have relaxing, anti-anxiety and anti-convulsive properties, the notion that theanine could have a calming effect seemed reasonable.

The theanine content of tea varies, with “matcha” tea being particularly rich. Unlike regular green tea made by extracting the components of tea leaves into hot water, “matcha” is prepared by stirring powdered green tea leaves into water, whisking with a brush to produce a foamy, grassy-tasting beverage. Not any old tea leaves, mind you, but ones that during the final stages of growth have been shaded from the sun with black netting before being stone-ground into a powder. Lack of sun forces the leaves to produce more of the green pigment chlorophyll as well as more caffeine, epigallocatechin gallate (EGCG) and theanine in the leaves meaning that drinking a matcha concoction is sort of like drinking concentrated tea. The espresso of teas, as it were. Matcha has a long history of use by the Japanese, especially Zen monks, in traditional tea ceremonies. As far as taste goes? If you like wheat grass juice, it’s for you.

Matcha also has a high content of EGCG, a member of the class of compounds known as polyphenols that have antioxidant properties. Although there is a theoretical basis for suggesting that antioxidant intake can mitigate disease and slow aging, there is no compelling evidence that consuming polyphenols has clinical benefit. What is known is that consuming plant-based products seems to confer benefit and that may be due to polyphenols, but of course plants contain numerous other compounds as well that may play a role.

As far as clinical evidence for the stress-relieving or anti-anxiety effect of theanine goes, there is a paucity of data. One way to study the effects of chemicals on the brain is through electroencephalography (EEG), a non-invasive instrumental technique that can monitor brain wave activity. The brain emits weak electrical impulses of varying frequencies that correlate with different types of mental states and activity. Deep sleep, for example, is characterized by low frequency “Delta” waves, while during light sleep “Theta” waves are emitted. A relaxed, awake state is associated with “Alpha” waves, and an awake and excited brain will emit high frequency “Beta” waves. Caffeine can be shown to suppress Theta and Alpha waves, while promoting the Beta waves that are linked with stress and anxiety. So, what does theanine do?

A number of studies have confirmed that within 30 minutes of ingesting theanine, there is a measurable enhancement of Alpha wave activity, implying an alert but relaxed state. Interesting, but is the amount of theanine used in such studies comparable to that found in tea or in fortified beverages? And does the small increase in Alpha activity translate into enhanced performance on tasks that require focus and attention?

The studies used 50-250 mg of theanine, which in general is more than that found in a cup of tea (2-100 mg). Tiger Focus and Slow Cow each have 25 mg per serving (240 mL), so they are decidedly on the low end of any dose that may have an effect on brain waves. More bothersome is the lack of any significant effect on subjects’ performance on attention tests even at doses of 250 mg. And when anxiety states were experimentally induced, such as asking subjects to prepare a presentation in a short time frame, administration of 200 mg of theanine was of no help.  Interestingly, neither was administration of 1 mg of alprazolam (Xanax), a standard anti-anxiety prescription medication. 

So theanine doesn’t seem to do a whole lot for humans. But if you’re a rodent in need of a little memory improvement, there’s hope. Rats placed in a box with some foreign object will explore it until they get bored. When in a subsequent experiment they are placed back in the box, now equipped with a new object in addition to the old one, the difference between the time taken to explore the two objects is a measure of memory. Supposedly, if the rat remembers having seen an object before, it will have less of a tendency to explore it again. Well, when rats are given theanine in their drinking water, they do reduce their “reexploration” time somewhat. The catch is that the animals’ average daily intake was 400 mg of theanine, which, taking body weight into account, would translate to several hundred liters of Slow Cow or Tiger Focus for a human. At such a dose the focus would be on going to the bathroom.

Tiger Woods of course was a superb golfer long before his foray into the sport beverage market. Any suggestion that his concentration has been helped by Tiger Focus is pure folly.  Such silliness is enough to make one search for a calming drink.

About the author

Dr. Joe Schwarcz is Director of McGill University’s “Office for Science and Society” which has the mission of separating sense from nonsense. He is well known for his informative and entertaining public lectures on topics ranging from the chemistry of food to the connection between the body and the mind. Professor Schwarcz has received numerous awards for teaching chemistry and for interpreting science for the public and was the first non-American ever to win the American Chemical Society’s prestigious Grady-Stack Award for demystifying chemistry. Professor Schwarcz hosts "The Dr. Joe Show" on Montreal's CJAD and has appeared hundreds of times on The Discovery Channel, CTV, CBC, TV Ontario and Global Television. He also writes a newspaper column entitled “The Right Chemistry”, and has authored eighteen books.
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