L-theanine is a chemical compound extracted from tea leaves known for its antioxidant properties and relaxing effects. You should avoid L-theanine when pregnant due to insufficient research regarding the safety of the compound on fetal development.
Always consult your physician before ingesting any type of herbal supplement or tea during pregnancy.
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L-theanine, an amino acid derived from tea leaves and Boletus badius mushroom, is absorbed by the small intestine and crosses the blood-brain barrier. The amino acid is structurally related to glutamic acid, a neurotransmitter in the brain, and increases dopamine levels in the brain. While L-theanine is present in most varieties of tea, the oxidation of black tea destroys the presence of the amino acid. L-theanine is also available as a dietary supplement in health food stores.
Naturally present in green and white tea, L-theanine, when paired with caffeine, reportedly increases alertness and improves cognitive function. According to research published in February 2008 in the journal "Biological Psychology," beverages containing a combination of L-theanine and caffeine improved cognitive function and alertness in participants more than beverages containing only caffeine. L-theanine may aid in stress relief by producing a relaxing effect, and it may play a role in preventing certain cancers. More research is necessary to test the validity of these claims. There are no benefits of L-theanine directly related to pregnancy.
Nonherbal Teas and Pregnancy
Nonherbal teas, including green and oolong, contain both L-theanine and caffeine. Even decaffeinated versions of nonherbal teas contain traces of caffeine. Although nonherbal teas provide various health benefits, the caffeine content may be unsafe during pregnancy. Caffeine crosses the placenta and may affect the development of the fetus. Consult your obstetrician or midwife about the safety of caffeine before drinking nonherbal teas during pregnancy.
Adverse side effects may occur as a result of ingesting tea extracts or dietary supplements. These side effects include gastrointestinal problems, headache and dizziness. Avoid L-theanine during pregnancy due to a lack of scientific research regarding the safety and efficacy of the compound. Always consult your physician before using any type of dietary supplement during pregnancy.
- American Pregnancy Association; Drinking Herbal Teas During Pregnancy; June 2011
- Memorial Sloan-Kettering Cancer Center; L-Theanine; December 2010
- Drugs.com: L-Theanine
- "Biological Psychology"; The Effects of L-Theanine, Caffeine and Their Combination on Cognition and Mood; C.F. Haskell, et al.; February 2008