L-theanine, that by-now famous constituent of green tea, can be like your best friend –calming you down and lifting your mood with a smile. Theanine was first studied as an anxiolytic – it was shown to reduce anxiety. Calmness in a tea cup! Theanine was, in fact, found to increase the alpha waves in your brain – those waves that relax the mind without causing sedative effects. Alpha waves are always associated with calm and meditation, but also with increases in your ability to focus and be alert. So good for students just before an exam!
Your Primary Inhibitory Neurotransmitter, GABA, and Theanine
Another way in which theanine calms you down is by increasing your primary inhibitory neurotransmitter, GABA and a third way is that it counters the stimulatory effects of caffeine. However, theanine, and by association, green tea, is now known to do a lot more for you! It may be able to reduce increases in blood pressure and heart rate during acute stress in folks who, shall we say, are high-strung., It has been shown to reduce the amyloid plaques in the brain—plaques associated with worsening Alzheimer’s Disease, and improve cognition and memory. Theanine can also protect the brain from various forms of toxic insults and free radical damage.,, We know, too, that it helps reduce the damage that elevated glutamate does – a condition called excitotoxicity, and so protects neurons from excessive glutamate stimulation., And the good news is that it provides you with all these benefits in the amounts of tea you would normally drink—a couple cups, or take in supplement form (50-200mg).
So relax, have yourself a cup of green tea and know that you are doing your brain good!
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 Nathan PJ, op. cit.
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