Green tea
| credits: sciencedaily.com
| credits: sciencedaily.com
Green
tea is said to have many putative positive effects on health. Now,
researchers at the University of Basel are reporting first evidence that
green tea extract enhances the cognitive functions, in particular the
working memory. The Swiss findings suggest promising clinical
implications for the treatment of cognitive impairments in psychiatric
disorders such as dementia. The academic journal Psychopharmacology has
published their results.
In the past the main ingredients of green
tea have been thoroughly studied in cancer research. Recently,
scientists have also been inquiring into the beverage’s positive impact
on the human brain. Different studies were able to link green tea to
beneficial effects on the cognitive performance. However, the neural
mechanisms underlying this cognitive enhancing effect of green tea
remained unknown.
Better memory
In a new study, the researcher teams of
Prof. Christoph Beglinger from the University Hospital of Basel and
Prof. Stefan Borgwardt from the Psychiatric University Clinics found
that green tea extract increases the brain’s effective connectivity,
meaning the causal influence that one brain area exerts over another.
This effect on connectivity also led to improvement in actual cognitive
performance: Subjects tested significantly better for working memory
tasks after the admission of green tea extract.
For the study healthy male volunteers
received a soft drink containing several grams of green tea extract
before they solved working memory tasks. The scientists then analyzed
how this affected the brain activity of the men using magnetic resonance
imaging (MRI). The MRI showed increased connectivity between the
parietal and the frontal cortex of the brain. These neuronal findings
correlated positively with improvement in task performance of the
participants. “Our findings suggest that green tea might increase the
short-term synaptic plasticity of the brain,” says Borgwardt.
Clinical implications
The research results suggest promising
clinical implications: Modeling effective connectivity among frontal and
parietal brain regions during working memory processing might help to
assess the efficacy of green tea for the treatment of cognitive
impairments in neuropsychiatric disorders such as dementia.
Genes increase stress of social disadvantage
Genes amplify the stress of harsh
environments for some children, and magnify the advantage of supportive
environments for other children, according to a study that’s one of the
first to document how genes interacting with social environments affect
biomarkers of stress.
“Our findings suggest that an
individual’s genetic architecture moderates the magnitude of the
response to external stimuli — but it is the environment that determines
the direction” says Colter Mitchell, lead author of the paper and a
researcher at the University of Michigan Institute for Social Research.
The study, published today in the
Proceedings of the National Academy of Sciences, uses telomere length as
a marker of stress. Found at the ends of chromosomes, telomeres
generally shorten with age, and when individuals are exposed to disease
and chronic stress, including the stress of living in a disadvantaged
environment.
