After four weekly doses of the drink, the team saw increased connectivity in regions of the brain associated with working memory.

"Drinking green tea improved memory in healthy people," said Borgwadt who stresses the small scale of the study and the associated limitations of their findings, but the team saw promise in the results.

"As it is a more natural kind of medication, [people] are more likely to change it," he said. "It could be helpful for diseases."

Since this research, interest in the cognitive benefits of green tea has grown and focused on the potential to improve symptoms of certain neurological, or psychiatric, disorders.

"[People thank] there is no hope and that people with Down syndrome cannot be treated due to its complexity," said Dierssen.

But she has set out to prove them wrong.

Taking on Down syndrome

The presence of the extra chromosome means people with the condition have more genes being expressed in their cells -- and more proteins being produced -- resulting in a range of physical and intellectual disabilities. These include decreased muscle tone, a flat face, slanted eyes and a range of potential learning disabilities.

"A number of genes are overexpressed and there is no way of tackling this overdose of genes," said Dierssen. Her team set out to find out any genes that contribute more greatly to the disease itself and found one key player, called DYRK1A.

"This gene causes a lot of the neurological and [physical] symptoms of Down Syndrome," she said.

By controlling the activity of this gene, and the proteins it expresses, the team could reduce some of the cognitive symptoms of the condition and the contender to have this control came in the form of the EGCG compound found commonly in green tea.

The tea potential

Those given EGCG performed better in tests for visual memory, the ability to control responses and the ability to plan or make calculations. Brain scans revealed improvements in connectivity between nerve cells and improvements were also seen in areas of the brain relating to language.

"This shows we can really target Down syndrome pharmacologically," said Dierrsen. For some patients, the effects lasted an additional six months after the study ended.

"This [study] confirms that you can give these extracts to have beneficial effects," said Borgwadt. "We need to know if these affects are specific for Down syndrome or if it is a more general effect on brain diseases."

Dierssen stresses this is not a cure for the condition as all of the neurological changes caused by the condition cannot be overcome. "What we see is that we can improve functionality," she said.

Borgwadt added it would be far too optimistic to expect this to become a treatment for the disease as the size of the effect is unclear and patients with the condition experience a range of symptoms. "You see effects, but are they fully relevant to the patient?," asked Borgwadt.

The team also saw a difference between genders, which they will provide greater insight into in their next paper, but for their discovery to have true effect, the team must next trial the green tea compound in greater numbers of people.

Experts are also quick to highlight that simply drinking green tea will not help.

They next plan to also test the compound in children where there could be greater effect as the brain is more adaptable at younger ages. "We hope there will be more improvement in children," said Dierrsen.

The findings have also inspired experts like Borgwadt who are curious about any benefits against other neurological diseases.

"One could argue there is a more general affect of neuroprotection in the brain, so it could help other psychiatric diseases," he said.