L-theanine may boost attention for anxious folks: Study by Stephen Daniells
Daily supplements of L-theanine, an amino acid found in
tea, may help people with anxiety focus on their daily activities,
suggests a new study from Japan.
On the other hand, people with minimal anxiety levels did not
experience any benefits from supplementation, according to findings
published in the Journal of Functional Foods.
"Given that L-theanine is a relaxant, it is directly or
indirectly involved at the neurochemical level and thus it is
impacted by a number of neurotransmitter systems," wrote the
scientists from the University of Shiga Prefecture and Taiyo
"Therefore, 200 mg of L-theanine intake may help normal
people with high anxiety propensity to concentrate on their daily
The study used Taiyo Kagaku's Suntheanine-branded L-theanine
ingredient, and the Japanese company funded the study.
Relax and focus
L-theanine, an amino acid found in tea leaves, is thought to
help reduce stress, promote relaxation and improve the quality of
sleep. L-theanine is found in tea leaves in low concentrations
(less than 2 percent), which means that effective dosage levels (of
100 - 200mg/day) cannot be delivered from drinking tea.
Various health effects have been associated with L-theanine,
including relaxation, neuroprotective effects, and improved
During rest, L-theanine increases alpha activity in EEG models -
suggesting greater relaxation. Whilst the amino acid is known to
induce changes in alpha activity that indicates increased
attentional processing during tasks that require attention.
The new study confirmed the dose of 200 mg for "enhanced
performance in visual attention task, and reaction time response,
among the subjects with higher anxiety propensity
The Japanese researchers recruited 18 healthy University
students and assessed their anxiety levels using the manifest
anxiety scale (MAS).
Student with high anxiety were put in one group, while students
with minimal anxiety were put in another group. Both groups
received water or water plus 200 mg of L-theanine per 100 ml of
water. The test was performed repeatedly and assessments performed
between 15 and 60 minutes after ingestion.
Results showed that highly anxious students receiving the
L-theanine displayed a slowing of their heart rate, improved
attentional performance, and better reaction times, compared to
members of the same group receiving placebo.
No significant benefits were observed in the student with
"It is noteworthy to mention that unlike other conventional
anti-anxiety treatments, L-theanine did not result in increased
drowsiness, slowed reflexes, or impaired concentration," wrote
"Results of a present study showed that ingestion of 200 mg
of L-theanine changes the electrical activity in the brain by
increasing alpha electric band measured by EEG."
Source: Journal of Functional Foods
Published online ahead of print, doi:
"Effects of L-theanine on attention and reaction time
Authors: A. Higashiyama, H.H. Htay, M. Ozeki, L.R. Juneja, M.P.
Back to Health