L-theanine is an amino acid found in tea leaves and in small amounts in Bay Bolete mushrooms. When consumed in green or black tea, or as a supplement (usually in tablet form), L-theanine facilitates relaxation, helping induce a state of calm, attentive wakefulness. Its relaxing effects can also help you fall asleep and sleep more deeply. L-theanine’s relaxing effects are due to its ability to increase levels of brain-calming chemicals such as Gamma aminobutyric acid (GABA), serotonin and dopamine, while decreasing levels of chemicals that cause stress and anxiety.
Neuropathy sufferers know the pain, anxiety, and other effects that come with having this chronic condition. L-theanine through tea or supplements is another potential tool in our self care tool kits to support our overall well-being.
L-theanine: a myriad of benefits beyond relaxation
Research has additionally linked L-theanine – especially when taken concurrently with moderate levels of caffeine – with improved attention span, focus, and memory. These are known symptoms of brain fog which is common with many neuropathy sufferers. Since black and green tea contain less caffeine than coffee, you avoid spikes in your energy level. Many people therefore find they are more productive when they drink black or green tea instead of coffee. You can start to feel these beneficial effects in just 30 minutes.
Research also suggests that L-theanine may:
- lower resting heart rate and blood pressure
- improve the immune system – such as decrease the occurrence of respiratory tract infections, the common cold and influenza
- reduce intestinal tract inflammation
- reduce sinusitis
- limit fat accumulation and weight gain (by reducing appetite – an effect of green tea’s umami flavour)
Several studies also suggest that regular tea drinkers have lower rates of cancer:
- One study concluded that tea drinkers were 37% less likely to develop pancreatic cancer than non-tea drinkers.
- A study in China revealed that women diagnosed with ovarian cancer who drank at least one cup of green tea daily lived longer than those who did not.
Although research supports the benefits of L-theanine, and The US Food and Drug Administration (FDA) has classified L-theanine as “generally recognized as safe” (i.e. safe to use per the packaging guidelines) (1) more in-depth studies need to be conducted to definitively ascertain these findings.
Of course there are no guarantees, but any self care tip that may reduce cancer risk is one worth considering given the neuropathy-compounding impact cancer treatments can have on existing neuropathy sufferers.
Ask your physician
As always, you should consult your physician before starting to use products containing L-theanine (tea and/or supplements). This is especially important if you:
- have low blood pressure: L-theanine may exacerbate this condition
- take supplements that lower blood pressure (andographis, casein peptides, cat’s claw, coenzyme Q-10, fish oil, L-arginine, lyceum, stinging nettle)
- use medications for high blood pressure
- take stimulant medications
- take supplements containing high levels of caffeine
- are undergoing chemotherapy: Some compounds found in green tea may reduce the efficacy of some chemotherapy medications.
Drinking copious amounts of caffeinated teas can cause nausea and irritability.
If your physician agrees that you can take L-theanine, discuss how you want to take it (tea or supplement). If you prefer to drink tea, ask your physician to recommend consumption guidelines. If you want to take an L-theanine supplement (available in many pharmacies, usually as 200 mg tablets), ask your physician to recommend the dosage best for you.
(1) “Does L-theanine have health benefits?” Blog published in MedicalNewsToday on January 8, 2019. Author: Claire Sissons. Medically reviewed by Alan Carter, PharmD. https://www.medicalnewstoday.com/articles/324120#overview
“The effects of L-theanine, caffeine and their combination on cognition and mood”. Abstract published in Biological Psychology, Volume 77, Issue 2, February 2008, Pages 113-122. Authors: Crystal F. Haskell, David O. Kennedy, Anthea L. Milne, Keith A. Wesnes, Andrew B. Scholey. https://www.sciencedirect.com/science/article/pii/S0301051107001573
“10 Evidence-Based Benefits of Green Tea”. Post on Healthline updated April 6, 2020. Author: Kris Gunnars, BSc. Medically reviewed by Atli Arnarson BSc PhD. https://www.healthline.com/nutrition/top-10-evidence-based-health-benefits-of-green-tea#2.-May-improve-brain-function
“Shared benefits of green and black tea”. Post on Healthline dated November 6, 2019. Author: Sharon O’Brien. https://www.healthline.com/nutrition/green-tea-vs-black-tea#shared-benefits
“What Does Gamma Aminobutyric Acid (GABA) Do?” Post on Healthline updated March 7, 2019. https://www.healthline.com/health/gamma-aminobutyric-acid
“What You Should Know About L-Theanine”. Post on Healthline updated March 7, 2019. https://www.healthline.com/health/l-theanine. Author: Foram Mehta. Medically reviewed by Debra Rose Wilson, PhD, MSN, RN, IBCLC, AHN-BC, CHT.
“L-theanine: properties, synthesis and isolation from tea”. Abstract published in Journal of the Science of Food and Agriculture, 29 March 2011. Quan V. Vuong, Michael C. Bowyer, Paul D. Roach. https://onlinelibrary.wiley.com/doi/abs/10.1002/jsfa.4373
“What you Need to Know About L-theanine”. Psychology Today post of August 29, 2017. Author: Michael J. Breus, Ph.D. https://www.psychologytoday.com/ca/blog/sleep-newzzz/201708/what-you-need-know-about-l-theanine
“L-theanine – a unique amino acid of green tea and its relaxation effect in humans”. Abstract published in Trends in Food Science & Technology, Volume 10, Issues 6-7, June 1999, Pages 199-204. Authors: Lekh Raj Juneja, Djong-Chi Chu, Tsutomu Okubo, Yukiko Nagato, Hidehiko Yokogoshi. https://www.sciencedirect.com/science/article/abs/pii/S0924224499000448
“Theanine: Uses and Risks”. Article published in WebMD. https://www.webmd.com/vitamins-and-supplements/theanine-uses-and-risks
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