L-Theanine Benefits for Parkinson’s Disease

A few months before my family member was diagnosed with Parkinson's disease (PD), she had difficulty sleeping through the night. First, we tried all the standard therapies I use with clients - meditation, cutting off caffeine after lunch, room darkening, etc. None worked.

I’m fortunate to have taught functional nutrition for close to 2 decades, so naturally, I went to a nutrition solution. I recommended 200 mg of L-theanine — an amino acid known to give your zzz’s a helping hand.

Noticing the effects

Low and behold, her dreams were answered! When she found herself with an empty bottle and no time to get another, it wasn’t long before her poor sleep returned.

Yet, as soon as she got her refill of L-theanine, the restorative and uninterrupted sleep ensued. A simple fix to a big problem that worked for her.

Parkinson's and sleep issues

Getting a good night’s sleep with Parkinson’s disease can be a s-t-r-u-g-g-l-e. In fact, approximately two-thirds of people with PD report poor quality of sleep.1

And like with my family member, sleep disturbances have become a potential early sign of PD. Not to mention, cognitive decline can also worsen sleep quality. So, addressing sleep quality was a top priority.1

Research shows that L-theanine, a mighty amino acid aids in the control of metabolic enzymes that contribute to sleep regulation. One study found that increased consumption of L-theanine helped participants fall asleep faster and for longer in a dose-response manner.2

Talk to your doctor

But fear not; This amino acid will not transform you into a drowsy zombie. Instead, it may help improve overall relaxation and restorative sleep. But with any supplement, it’s always important to find a safe brand and dosage.

When possible, work with a dietitian specializing in functional nutrition and check with your doctor and pharmacist for drug and supplement interactions or contraindications if you consider trying a supplement for sleep.

Slowing disease progression

While L-theanine may help manage symptoms associated with PD, it also can help provide neuroprotection that may aid in slowing down its progression.3

Specifically, L-theanine helps protect against neuron degradation — ultimately increasing dopamine, serotonin, and other necessary neurotransmitters. L-theanine may have an impact on improving attention, and therefore, memory.3

Along with its neuroprotective properties, L-theanine may also benefit people with Parkinson’s disease through its antioxidant content and anti-inflammatory properties.4

These qualities may contribute to improvements in motor behavioral abnormalities, overall dopamine levels, and slowed neurological cell death. In other words, there are multiple mechanisms by which L-theanine could potentially benefit people with Parkinson’s disease.4

Natural food sources of L-theanine

Time to "spill the tea!" The inside scoop says that people may reap the sleep and Parkinson’s disease protection benefits of L-theanine by enjoying a cup of their favorite green or black tea.5

While there is only approximately 20 mg of L-theanine per cup of black tea - an amount that is significantly less than the suggested therapeutic doses, healthy individuals still showed improvements in cognitive function.5

In other words, a practical and more consumable dietary dose of L-theanine may still result in therapeutic benefits for people with Parkinson’s disease.

Supplement option

If food sources of L-theanine are not your cup of tea, supplementation is another option. Although the verdict is still pending on L-theanine and research is evolving, if you decide to take it, remember to consult with a dietitian and doctor to determine its appropriateness and dosage safety. 

Your doctor can recommend the correct dosage of L-theanine to experience positive changes in sleep habits, stress, and cognitive function.

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