Daily supplements of a green tea extract may boost mental alertness and enhance memory, according to a randomized, double-blind, placebo-controlled study from Korea.
A combination of a green tea extract with L-theanine was associated with improvements in immediate and delayed recall, and general memory, according to findings published in the Journal of Medicinal Foods.
“As a natural ingredient with a long history of consumption, LGNC-07 [ – a combination of green tea extract and L-theanine - ] should be considered as a potential nutraceutical candidate for enhancing cognitive performance,” wrote researchers from
The study was funded by Korea’s LG Household & Health Care, Ltd., which also produced the ingredient used in the study, and provided one of the co-authors for the paper.
The majority of science on tea has looked at green tea, with benefits reported for reducing the risk of Alzheimer's and certain cancers, improving cardiovascular and oral health, as well as aiding in weight management.
Green tea contains between 30 and 40 per cent of water-extractable polyphenols, while black tea (green tea that has been oxidized by fermentation) contains between 3 and 10 per cent. Oolong tea is semi-fermented tea and is somewhere between green and black tea. The four primary polyphenols found in fresh tealeaves are epigallocatechin gallate (EGCG), epigallocatechin, epicatechin gallate, and epicatechin.
The success has translated into a booming extract market, valued at a around $44m (€29.7m), according to recent report from Frost & Sullivan. The market is expected to grow by more than 13 per cent over the next seven years. Key players include DSM, Taiyo, and Tate & Lyle. Innovation in delivery has also seen companies like Maxx Performance release an encapsulated green tea extract for bakery applications.
L-theanine, an amino acid found in tea leaves, is thought to help reduce stress, promote relaxation and improve the quality of sleep. L-theanine is found in tea leaves in low concentrations (less than 2 percent), which means that effective dosage levels (of 100 – 200mg/day) cannot be delivered from drinking tea.
Ninety-one participants with mild cognitive impairment – a risk factor for Alzheimer’s disease – were recruited and randomly assigned to receive either 1,680 mg of the green tea extract-L-theanine combination (LGNC-07) or placebo (maltodextrin plus lactose) for 16 weeks.
A number of tests were used to assess memory and attention. Results showed that volunteers receiving the green tea supplement exhibited improvements in memory: ‘Marginal’ improvements were observed with regards to the delay in recognition, and ‘significant’ increases in memory regarding recall of word reading.
Electroencephalograms (EEG) were recorded in 24 volunteers, and these scans showed improvements in indicators of mental alertness in specific parts of the brain.
“There is a clear need for further studies to investigate the cognitive improvement effect of LGNC-07,” wrote the researchers. “These studies should have increased numbers of study subjects with various degrees of cognitive deficits. In particular, the finding that [a particular] subgroup […] showed a better response to LGNC-07 needs to be carefully considered.”
The mental benefits of tea and the L-theanine it contains have been the subject of interest and research by numerous companies, including multinational giants like Unilever. In 2008, the European Food Safety Authority (EFSA) turned down Unilever-submitted health claims linking black tea consumption and improved mental focus. The European scientific assessor said in January 2009 that the dossier failed to demonstrate causality.
A year later, Unilever scientists reported results of a randomized trial in the journal Appetite that tea (and L-theanine) may boost attention, although it did not report any benefits for alertness (Vol. 54, April 2010, pp. 406-409).
"We conclude that a high dose of L-theanine combined with caffeine, at the level of a single cup of tea, can help to improve attention,” wrote Suzanne Einöther from sensation, perception and behaviour at Unilever R&D Vlaardingen.
Source: Journal of Medicinal Food
Volume 14, Issue 4, Pages 334-343
“A Combination of Green Tea Extract and l-Theanine Improves Memory and Attention in Subjects with Mild Cognitive Impairment: A Double-Blind Placebo-Controlled Study”
Authors: S-K. Park, I-C. Jung, W.K. Lee, Y.S. Lee, H.K. Park, H.J. Go, et al.