Drinking tea may improve memory and help protect against Alzheimer’s and dementia. According to a Japanese study, elderly volunteers who consumed green tea showed a significantly lower decline in cognitive function when compared to a placebo group.
The researchers focused on a compound in tea called “theanine.” Theanine resembles glutamate, a neurotransmitter related to memory. They found that once theanine passes through the blood-brain barrier, it exerts a brain-protective effect. They also found that theanine helps prevent cell death after a mini-stroke.
Other studies suggest that the combination of theanine and caffeine may improve cognitive function. In particular, a dose of theanine and caffeine before a demanding cognitive task may significantly improve accuracy and alertness. Theanine has been shown to reduce mental and physical stress, improve cognition, and boost mood in a synergistic manner with caffeine.
So what teas have the most L-theanine? Gyokuro contains the highest levels, 2% by dry weight. Gyokuro is a shade grown green tea that is high in antioxidants. Gyokuro forms the base of our Izu Matcha, Bilberry Matcha, and Samurai Matcha. Matcha teas are powdered, and thus infused directly with water or in smoothies. This provides the highest concentration of beneficial compounds.
Teas that are minimally oxidized posses high levels of L-theanine as well. Our line of white teas are the least oxidized, followed by our line of green teas.
Oolong and black teas possess the least amount of L-theanine. However, these oxidized teas provide other beneficial compounds not present in green or white tea.
SOURCES:
Song, J., et al., "Tea and cognitive health in late life: current evidence and future directions," J. Nutr. Health Aging, Jan. 2012; 16(1): 31–4.)
Kakuda, T., "Neuroprotective effects of theanine and its preventive effects on cognitive dysfunction," Pharmacol. Res., Aug. 2011; 64(2): 162–8.)
Gomez-Ramirez M; Higgins, BA; Rycroft, JA; Owen, GN; Mahoney, J; Shpaner, M; Foxe, JJ (2007). "The Deployment of Intersensory Selective Attention: A High-density Electrical Mapping Study of the Effects of Theanine". Clin Neuropharmacol 30 (1): 25–38. doi:10.1097/01.WNF.0000240940.13876.17. PMID 17272967.
Kimura K, Ozeki M, Juneja L, Ohira H (2007). "L-Theanine reduces psychological and physiological stress responses". Biol Psychol 74 (1): 39–45. doi:10.1016/j.biopsycho.2006.06.006. PMID 16930802.
Park SK. Jung IC. Lee WK. Lee YS. Park HK. Go HJ. Kim K. Lim NK. Hong JT. Ly SY. Rho SS. (2011). "A combination of green tea extract and l-theanine improves memory and attention in subjects with mild cognitive impairment: a double-blind placebo-controlled study". Journal of Medicinal Food 14 (4): 334–343. doi:10.1089/jmf.2009.1374. PMID 21303262.
Haskell CF, Kennedy DO, Milne AL, Wesnes KA, Scholey AB (2008). "The effects of l-theanine, caffeine and their combination on cognition and mood". Biol Psychol 77 (2): 113–22. doi:10.1016/j.biopsycho.2007.09.008. PMID 18006208.
"Distracted? Tea might help your focus". sciencenews.org. September 29th, 2007. "John J. Foxe of the Nathan S. Kline Institute for Psychiatric Research in Orangeburg, N.Y.
