With something as basic and necessary as sleep, it’s puzzling and troubling that so many people have problems with it.
Insomnia and other sleep disorders are prevalent: the American Sleep Association estimates that between fifty and seventy million American adults suffer from a sleep disorder. (1)
While many choose over-the-counter or pharmaceutical sleep aids, these come with a variety of side effects and other serious implications. Working with your body’s own chemistry may offer a more long-lasting and healthy alternative.
Drinking green tea before bed, on the other hand, is a natural solution to your sleep problems. L-theanine is an amino acid that is found in many plant species but in only two that we consume: medicinal mushrooms and tea. We mean true tea from the Camellia sinensis plant, not herbal teas made from herbs, spices, and other types of plants (e.g., rooibos).
When ingested, L-theanine is able to penetrate the blood-brain barrier to affect neurotransmitters.
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L-theanine and the Brain
Firstly, L-theanine promotes mental alertness. (2) Its chemical structure is similar to that of glutamate, a stimulating neurotransmitter. Because of this, L-theanine readily binds to glutamate’s neuroreceptors and the effect in the brain is much the same as glutamate. This neurotransmitter modulates synaptic strength and speed. While binding to glutamate receptors, L-theanine blocks the transport of glutamate, further exciting cellular activity. (3)
Secondly, while stimulating neural activity, L-theanine reduces anxiety and stress by increasing serotonin, dopamine, and GABA (gamma-aminobutyric acid) hormones in the brain. (4) GABA is a hormone that is responsible for moderating feelings of fear or anxiety. Serotonin is an anxiolytic hormone (inhibits anxiety) that influences mood and is involved in the sleep process. Dopamine, on the other hand, is a hormone responsible for feelings of pleasure and well-being. Pharmaceuticals developed to treat anxiety and depression artificially block some hormones with promoting the production of these three.
Thirdly, L-theanine stimulates alpha brain waves to improve relaxation, reduce anxiety, and promote calmness. (5)
Lastly, L-theanine stimulates cognition and memory without raising blood pressure and stress. (6)
The Chemistry of Tea
Black, green, white, yellow, and oolong tea all contain L-theanine. These all come from the same plant but are processed differently to develop their flavor and caffeine content. The interaction between L-theanine and caffeine in tea is a synergistic marvel.
Caffeine alone, as found in coffee, can boost alertness and mental acuity but once it wears off, there’s often an energy crash. In tea, L-theanine and caffeine work together to enhance the performance of both while the neurostimulation of caffeine is balanced by calming hormones stimulated by L-theanine. (7)
Research into acute cognitive and mood effects of L-theanine and caffeine combined found better improved mental performance and decreased mental fatigue than with caffeine alone. (8) Essentially, you experience alertness without the caffeine crash.
“Tea has been shown to raise skin temperature to a higher level, to increase critical flicker fusion threshold, and to reduce physiological stress responses and increase relaxation ratings when compared with coffee or other control beverages matched for caffeine level,” writes the Journal of Nutrition. (9)