The new research is said to be the first study to measure the pharmacokinetic parameters of L-theanine – assessing how the compound is absorbed and removed from blood plasma after dietary ingestion.
The results of the study, published in the Journal of Functional Foods, are believed to provide new model data, which could support further research into the potential health benefits of L-theanine.
“The obtained set of pharmacokinetic parameters from this study allows accurate prediction of L-theanine concentrations in plasma over a relevant dose range.
“The ability to predict L-theanine concentration may facilitate research about putative health effects of L-theanine in the brain,” stated the Unilever scientists.
“The impact of the composition of other food matrices like sugar, milk and … ingested meals … on the pharmacokinetic behaviour of L-theanine is unknown and could be studied in future research,” they added.
Tea leaves contain numerous compounds, including caffeine and flavonoids – that dissolve when the leaves are mixed with hot water.
The amino acid L-theanine (c-glutamylethylamide) is almost exclusively found in tea plants. The compound only exists in the free form, and is the principal free amino acid in tea - accounting for approximately 50 percent of the total free amino acids.
Various health effects have been associated with L-theanine, including relaxation, neuroprotective effects, and improved attention.
During rest, L-theanine increases alpha activity in EEG models - suggesting greater relaxation. Whilst the amino acid is known to induce changes in alpha activity that indicates increased attentional processing during tasks that require attention.
In 1950 the Tea laboratory of Kyoto successfully separated theanine from Gyokuro leaf, which has the highest theanine content among all teas. Theanine is an analog to glutamine and glutamate, and can cross the blood-brain barrier and consequently has psychoactive properties including the ability to reduce physical and mental stress, improve cognition and mood.