GABA tea

thumb|Rolled GABA tea

'''GABA tea''' (other names: Gabaron, Jia Wu Long cha, Jing Bai Long cha, 佳叶龙茶) is tea that has undergone a special processing which leads to high accumulation of GABA (the chief inhibitory neurotransmitter in the central nervous system) in the tea leaves. This process involves storing the leaves in an oxygen-free nitrogen gas chamber.

This new way of processing tea was created in Japan by the former MAFF National Research Institute of Tea (currently the National Institute of Vegetables and Tea Science) in 1984. Dr. Tsushida and his collaborators at the MAFF<ref>{{cite journal |author=Tojiro Tsushida |author2=Toshinobu Murai |author3=Masashi Omori |author4=Jyunko Okamoto |title=Production of a New Type Tea Containing a High Level of gamma-Aminobutyric Acid |journal=Nippon Nogeikagaku Kaishi |year=1987 |volume=61 |issue=7 |pages=817–822 |doi=10.1271/nogeikagaku1924.61.817 |url=https://www.jstage.jst.go.jp/article/nogeikagaku1924/61/7/61_7_817/_article |access-date=2016-10-05|doi-access=free }}</ref> began developing GABA-rich tea in 1984 and successfully produced a new type tea in which almost all glutamic acid has been converted to GABA without changing the content of catechin or caffeine. They found that a large amount of GABA accumulated in green tea through six to ten hours in an anaerobic (oxygen-free) chamber filled with nitrogen. They examined further the GABA content of green, oolong and black tea made under such anaerobic conditions and found that GABA accumulated in all teas.

Japanese scientists have shown great interest and attention to this new technology. In the late 1980s in Japan, this GABA tea was actively distributed as a commercial product for people with hypertension. It was found that the chemically synthesized GABA reduces blood pressure in experimental animals<ref>{{cite journal |author=Masashi Omori |author2=Toshiko Yano |author3=Junko Okamoto |author4=Tojiro Tsushida |author5=Toshinobu Murai |author6=Mitsuru Higuchi |title=Effect of Anaerobically Treated Tea (Gabaron Tea) on Blood Pressure of Spontaneously Hypertensive Rats |journal=Nippon Nogeikagaku Kaishi |year=1987 |volume=61 |issue=11 |pages=1449–1451 |doi=10.1271/nogeikagaku1924.61.1449 |url=https://www.jstage.jst.go.jp/article/nogeikagaku1924/61/11/61_11_1449/_article |access-date=2016-10-05|doi-access=free }}</ref><ref>{{cite journal |vauthors=Stanton HC |title=Mode of action of gamma amino butyric acid on the cardiovascular system |journal=Arch Int Pharmacodyn Ther |volume=143 |pages=195–204 |date=May 1963 |pmid=13983416 }}</ref> and humans.<ref>{{cite journal |vauthors=Elliott KA, Hobbiger F |title=gamma Aminobutyric acid; circulatory and respiratory effects in different species; re-investigation of the anti-strychnine action in mice |journal=J Physiol |volume=146 |issue=1 |pages=70–84 |date=April 1959 |pmid=13655216 |pmc=1356890 |doi=10.1113/jphysiol.1959.sp006178 }}</ref> Further research demonstrated that GABA tea was also able to reduce the blood pressure in experimental animals and humans.<ref>{{cite journal |vauthors=Abe Y, Umemura S, Sugimoto K, Hirawa N, Kato Y, Yokoyama N, Yokoyama T, Iwai J, Ishii M |title=Effect of green tea rich in gamma-aminobutyric acid on blood pressure of Dahl salt-sensitive rats |journal=Am J Hypertens |volume=8 |issue=1 |pages=74–9 |date=January 1995 |pmid=7734101 |doi=10.1016/0895-7061(94)00141-w }}</ref><ref>{{cite journal |vauthors=Hakamata K |title=Anaerobically treated tea and its hypotensive effects |journal=Jpn. Agric. Res. Q. |volume=24 |pages=105–110 |date=1990 |doi= |url=https://www.jircas.go.jp/sites/default/files/publication/jarq/24-2-105-110_0.pdf}}</ref><ref>{{cite journal |vauthors=Lin SD, Mau JL, Hsu CA |title=Bioactive components and antioxidant properties of γ-aminobutyric acid (GABA) tea leaves |journal=LWT-Food Science and Technology |volume=46 |issue=1 |pages=64–70 |date=2000 |doi=10.1016/j.lwt.2011.10.025 |url=https://www.sciencedirect.com/science/article/pii/S0023643811003525|doi-access=free }}</ref>{{Full citation needed|date=March 2021}}

GABA tea production was also widely adopted by Taiwanese tea makers. GABA oolong teas from Taiwan are also another common type of GABA tea.

Traditionally it was thought that exogenous GABA did not penetrate<ref name=Kuriyama>{{cite journal | vauthors = Kuriyama K, Sze PY | title = Blood–brain barrier to H3-γ-aminobutyric acid in normal and amino oxyacetic acid-treated animals | journal = Neuropharmacology | volume = 10 | issue = 1 | pages = 103–108 | date = January 1971 | pmid = 5569303 | doi = 10.1016/0028-3908(71)90013-X }}</ref> the blood–brain barrier, however more current research indicates that it may be possible, or that exogenous GABA (i.e. in the form of nutritional supplements) could exert GABAergic effects on the enteric nervous system which in turn stimulate endogenous GABA production.<ref>{{Cite journal|last1=Boonstra|first1=Evert|last2=de Kleijn|first2=Roy|last3=Colzato|first3=Lorenza S.|last4=Alkemade|first4=Anneke|last5=Forstmann|first5=Birte U.|last6=Nieuwenhuis|first6=Sander|date=2015-10-06|title=Neurotransmitters as food supplements: the effects of GABA on brain and behavior|journal=Frontiers in Psychology|volume=6|page=1520|doi=10.3389/fpsyg.2015.01520|issn=1664-1078|pmc=4594160|pmid=26500584|doi-access=free}}</ref>

Some studies have indicated that GABA tea consumption can also decrease stress.<ref>{{cite journal |vauthors=Hinton T, Jelinek HF, Viengkhou V, Johnston GA, Matthews S |title=Effect of GABA-Fortified Oolong Tea on Reducing Stress in a University Student Cohort |journal=Front Nutr |volume=6 |issue= |article-number=27 |date=2019 |pmid=30972340 |pmc=6443991 |doi=10.3389/fnut.2019.00027 |doi-access=free}}</ref> A 2020 review in ''Frontiers in Neuroscience'' found that oral GABA intake "may have beneficial effects on stress and sleep", but also stated that further research is needed.<ref>{{Cite journal |last1=Hepsomali |first1=Piril |last2=Groeger |first2=John A. |last3=Nishihira |first3=Jun |last4=Scholey |first4=Andrew |date=2020-09-17 |title=Effects of Oral Gamma-Aminobutyric Acid (GABA) Administration on Stress and Sleep in Humans: A Systematic Review |journal=Frontiers in Neuroscience |volume=14 |article-number=923 |doi=10.3389/fnins.2020.00923 |doi-access=free |pmc=7527439 |pmid=33041752}}</ref>

==References== {{reflist}}  {{refbegin}} *{{cite journal |vauthors=Wang HF, Tsai YS, Lin ML, Ou AS |title=Comparison of bioactive components in GABA tea and green tea produced in Taiwan |journal=Food Chemistry |volume=96 |issue=4 |pages=648–653 |date=2006 |doi=10.1016/j.foodchem.2005.02.046 }} {{refend}}

Category:Herbal and fungal stimulants Category:Tea