Its Found In Green Tea and May Help PMS

What is Theanine?

Theanine is a centrally active amino acid commonly extracted from green tea. This amino acid is an analog of glutamic acid and is structurally similar to the excitatory neurotransmitter, glutamate.

Theanine is most widely used in Japan where it is not only found in green tea but also added to foods because of its distinct umami taste.  In that country, the amino acid is also added to herbal teas, soft drinks, boxed cereals, chocolate, and chewing gum.

Many varieties of black tea also contain theanine in different amounts with Darjeeling Gastelton holding the highest amount of the amino acid (250 mg for every 100 g of the tea).

In the US, the FDA (Food and Drug Administration) categorizes theanine as a GRAS (generally regarded as safe) ingredient.

Drinks and supplements containing theanine are either marketed to help increase mental focus or to promote relaxation. The L-form (rather than the D-form) of the amino acid is found in green tea. L-theanine is also the form included in drinks and supplements.

The Medicinal Effects of Theanine

Theanine can cross the blood-brain barrier easily. Its psychoactive properties in the brain are responsible for most of the therapeutic uses of the amino acid.

Although theanine is structurally similar to glutamate, it does not have the same excitatory effect in the central nervous system. Contrary to expectations, theanine only has a weak affinity for glutamate receptors.

In fact, clinical trials show that theanine reverses glutamate-induced neurotoxicity. Therefore, the amino acid can help prevent neurodegenerative brain diseases.

Rather than promote increased brain activity like glutamate, theanine rather raises the level of GABA (gamma-aminobutyric acid), an inhibitory neurotransmitter. However, theanine also increases dopamine levels in the brain.

These effects result in reduced mental and physical stress as well as improvement in mood and cognitive performance.

It is possible that theanine may also affect serotonin levels in the brain but while some studies found that the amino acid raised serotonin concentration, some others found that it reduced serotonin levels.

Theanine reduces stress and has a calming effect on the body by promoting the generation of alpha waves in the brain. This brain wave activity is associated with relaxation. On the other hand, theanine can promote increased alertness, mental focus and cognitive performance especially when it is combined with caffeine.

Besides its beneficial roles in the central nervous system, theanine can also boost the immune system. Specifically, it increases the ability of gamma delta T cells to fight infections.

Theanine can also raise the production of antibacterial proteins and prevent the release of histamine from mast cells.

How Theanine Can Help PMS

L-theanine can help improve the symptoms of premenstrual syndrome (PMS) involving emotions. Specifically, it can reduce depression, anxiety, mood changes, irritability, and mental fatigue.

How does theanine help PMS? By simultaneously increasing dopamine and GABA levels in the brain while also increasing alpha wave activities.

Theanine and Alpha Wave Activity

There are generally 4 types of brain wave activities and they are briefly explained in the table below.

Therefore, the alpha wave activity promoted by L-theanine is the best of both worlds. It leaves you relaxed without being sedated and it also leaves you alert without being worried.

In a study published in the journal, Trends in Food Science and Technology, in June 2009, a group of researchers demonstrated the anxiolytic effect of theanine in young women aged 18 – 22 years.

In that study, each of the women was given one of water, 50 mg or 200 mg of L-theanine once every week.

At the end of the study, only those who received both doses of L-theanine experienced reduced anxiety and increased alpha wave activity. And the best anxiolytic effect was observed with the 200 mg dose of L-theanine.

Because these are desirable outcomes for women with PMS, this study supports the use of L-theanine in the management of PMS.

Theanine and Mood

L-theanine can promote relaxation by other means besides increasing alpha wave activity. Studies confirm that this green tea amino acid can raise the concentration of dopamine in the brain.

Dopamine is a “feel-good” neurotransmitter. By raising its level in the brain, L-theanine can verily help fight PMS-related depression and other mood changes.

In addition, there is evidence (although contested) that theanine can also raise the level of serotonin, another neurotransmitter involved in mood. Besides regulating mood, serotonin is also important to sleep, memory formation and learning.

Lastly, theanine can also improve mood by increasing the GABA levels in the brain.

Although GABA is an inhibitory neurotransmitter, it can help stabilize the effects of excitatory neurotransmitters. Therefore, GABA can contribute to the prevention of mood swings by counteracting the kind of neurotransmitter imbalances that promote mood swings and irritability.

In addition, by serving as an inhibitory neurotransmitter, GABA promotes mental relaxation by reducing brain activity from a predominant beta wave dominance to the calming alpha wave activity.

Other Benefits of Theanine

L-theanine may also improve PMS symptoms by other means. For example, the amino acid has been shown to bring down high blood pressure and rapid heart rates.

Both of these cardiovascular events can be due to stress. Therefore, the positive effect of the amino acid on the blood pressure and heartbeat can contribute to its anti-stress activities. This is important because stress is one of the triggers of PMS.

Secondly, the immune-boosting activities of L-theanine can make an indirect contribution to the improvement of PMS symptoms.

By improving the ability of the immune system to fight infections and harmful free radicals, L-theanine can help prevent the various hormonal and neurotransmitter imbalances responsible for most of the symptoms of PMS.

Thirdly, studies show that theanine improves learning and concentration. Maintaining mental focus and cognitive performance can be difficult for women with PMS because of the neurotransmitter storm that occurs during that stage of their menstrual cycle.

Therefore, another benefit of the calming effect of L-theanine is the improvement in mental ability.

A 2007 study found that combining 100 mg of L-theanine and 60 mg of caffeine (the amounts found in 4 cups of green tea) significantly improved brain activity and performance of mental tasks.

However, care should be taken with consuming caffeine because it can worsen PMS symptoms.

Lastly, the end result of the alpha wave activity promoted by L-theanine is improved sleep at night.

Insomnia and sleep disturbance are common complaints among women with PMS and they are caused by the same neurotransmitter storm mentioned above.

Getting the recommended 7 – 8 hours of sleep every night can help women cope with their PMS symptoms. And L-theanine can help them relax enough to sleep better at night.

Clinical Evidence to Support the Use of Theanine for PMS

This study conducted by researchers from the University of Shizuoka in Japan is often quoted in the discussion of L-theanine supplementation for PMS.

The study built on past observations of the effects of theanine on the concentrations of certain neurotransmitters and also on brain wave activity.

For the study, the researchers recruited 7 women with PMS and gave each of them either placebo or L-theanine from the start of the ovulatory phases of their menstrual cycles to the beginning of the menstrual flow.

The result of this study showed that L-theanine reduced both the mental and physical symptoms of PMS when compared to the placebo.

In addition, the improvement in symptoms even continued to the menstrual phase where L-theanine also reduced both physical and mental symptoms.

The researchers, therefore, concluded that L-theanine was effective in the management of PMS symptoms. They linked this improvement to the increase in alpha wave activity prompted by the amino acid although its exact mechanism of action was unknown.