Japanese researchers conducting an investigation of elderly persons with normal or slight cognitive dysfunction found that high concentrations of theanine significantly lowered decline in cognitive function compared to a placebo group.
This result suggested that theanine might even be able to improve cognitive dysfunction in elderly persons, according to the Doctors Health Press e-Bulletin.
Theanine is found in tea leaves. It has a similar chemical structure to glutamate, which is a neurotransmitter related to memory. The Japanese research team found that once theanine passes through the blood-brain barrier, it exerts a brain-protective effect.
They also found that the tea compound exerts a preventive effect on neuronal cell death after transient cerebral ischemia (a mini-stroke). The fewer brain cells that die during one of these mini-strokes, the better the chances are of recovering without any brain damage—which is exactly what theanine seems to help with.
The report “How Drinking Tea Could Lead to Better Memory,” also lists other studies that suggest a combination of theanine and caffeine improves cognitive performance. These studies say that a dose of theanine and caffeine prior to performing a demanding cognitive task may significantly improve accuracy and alertness. These two ingredients together could help increase the ability to focus.
SOURCE: Song, J., et al., “Tea and cognitive health in late life: current evidence and future directions,” J. Nutr. Health Aging, Jan. 2012; 16(1): 31–4.)
Kakuda, T., “Neuroprotective effects of theanine and its preventive effects on cognitive dysfunction,” Pharmacol. Res., Aug. 2011; 64(2): 162–8.)