Tea will naturally contain both theanine and caffeine, but will it work, as well as supplemental theanine and caffeine?
You want to know why the researchers from the Universities of Peradeniya, Kelaniya and the Texas Tech University know that? Let's take a look at what the researchers did and why they conclude that the effects of caffeine & theanine add up.
In a placebo-controlled, five-way crossover trial in 20 healthy male volunteers, Chanaka N. Kahathuduwa et al. compared the effects of l-theanine (200 mg), caffeine (160 mg), their combination, black tea (one cup) and a placebo (distilled water) on cognitive and neurophysiological measures of attention.
|Figure 1: Theanine and caffeine contents of 37 commercial white, green, oolong, black, and pu-erh tea samples were quantified by high-performance is a liquid chromatography-diode array detector (Boros. 2016).|
|Mean ± SE amounts of l-theanine in cups (200 ml) of commercially-available teas. Mean amounts of l-theanine (mg/200 ml) are also shown in brackets (Keenan. 2011) | rel. values for matcha tea are in the text.|
On the left hand side, you can see an overview of the theanine content of various commercial teas; in this context it is also worth pointing out that high grate matcha tea contains ~56% more than std. sencha green tea (for low grade gree tea, it's even more than 100% extra theanine in matcha vs. sencha | Goto. 1996).Lastly, I would like to point out that theanine is not just the "calming" partner of caffeine, more recent research shows that l-theanine has neuroprotective, nootropic, immune-modulating, anti-fatigue, anti-diabetic and anti-depressant effects that are almost on par with caffeine. If you want to learn more about these, check out Liang's latest review (Liang. 2015)
|Figure 2: Pre- ad post recognition visual reaction time (RVRT) latency and P110 visual evoked potential latencies, a measure of the reaction speed of your brain; abs. values in ms, rel. changes in % above the bars (Kahathuduwa. 2016).|
- Boros, Klára, Nikoletta Jedlinszki, and Dezső Csupor. "Theanine and Caffeine content of infusions prepared from commercial tea samples." Pharmacognosy Magazine 12.45 (2016): 75.
- Goto T., Yoshida Y., Amano I., Horie H., Foods Food Ingredients J. 170 (1996): 46-51.
- Juneja, Lekh Raj, et al. "L-theanine—a unique amino acid of green tea and its relaxation effect in humans." Trends in Food Science & Technology 10.6 (1999): 199-204.
- Haskell, Crystal F., et al. "The effects of L-theanine, caffeine and their combination on cognition and mood." Biological psychology 77.2 (2008): 113-122.
- Kahathuduwa, Chanaka N., et al. "Acute effects of theanine, caffeine and theanine–caffeine combination on attention." Nutritional Neuroscience (2016): 1-9.
- Keenan, Emma K., et al. "How much theanine in a cup of tea? Effects of tea type and method of preparation." Food chemistry 125.2 (2011): 588-594.
- Liang, Yue-Rong, et al. "Health Benefits of Theanine in Green Tea: A Review." Tropical Journal of Pharmaceutical Research 14.10 (2015): 1943-1949.