Espresso coffee could contain compounds that disrupt the progression of Alzheimer's disease.
A study published in the Journal of Agricultural and Food Chemistry found specific espresso compounds could potentially influence the onset of the disease.
The preliminary laboratory results do not confirm that drinking espresso will prevent Alzheimer's in humans.
However, they could be a stepping stone towards finding or designing other bioactive compounds against neurodegenerative diseases, including Alzheimer's.
Tackling build-up of tau proteins
A protein called tau helps to stabilise structures in a healthy brain, but these proteins can form clumps, or fibrils, in Alzheimer's disease and other neurodegenerative conditions.
This process is believed to play a significant role in the development and progression of these diseases.
Dr Mariapina D’Onofrio, from the University of Verona, and her colleagues decided to investigate whether certain compounds in espresso could inhibit tau aggregation.
To do this, the team carried out experiments using espresso shots made from store-bought beans.
Espresso's bioactive compounds
The researchers characterised the chemical make-up of the espresso using nuclear magnetic resonance spectroscopy, identifying several key compounds: caffeine and trigonelline (both alkaloids), genistein (a flavonoid), and theobromine (a compound also found in chocolate).
These compounds, along with the complete espresso extract, were incubated alongside a shortened form of the tau protein for up to 40 hours.
As the concentration of espresso extract, caffeine, or genistein increased, tau fibrils became shorter and did not form larger sheets.
The most dramatic results were observed with the complete espresso extract.
Further experiments revealed that caffeine and the espresso extract could bind preformed tau fibrils.
Shortened fibrils were found to be non-toxic to cells, and they did not act as “seeds” for further aggregation.
Dr D'Onofrio told The National: "The inhibition effect is similar to that observed in the case of other compounds such as limonoids, oleocanthal and curcumin.
"The interesting result of our study is that single compounds exert a lower effect than coffee blends.
"Moderate espresso coffee consumption – two or three cups per day – could provide an amount of biomolecules comparable to the concentrations that showed an antiaggregant effect in our study."
Implications and future research
While these findings provide exciting insights into the neuroprotective potential of espresso coffee, much more research is needed before the effects in humans can be confirmed.
Espresso, like other coffee beverages, contains more than a thousand compounds.
Though the bioactivity of the entire drink and its individual components have been explored, the exact mechanism by which these compounds affect tau proteins, and how this may translate into neuroprotective benefits for humans, remains unclear.
The research team's work suggests potential molecular scaffolds for designing therapies against neurodegenerative diseases, particularly those involving tau proteins.
Dr D'Onofrio said: "The primary aim of our study was to understand whether one of the most consumed beverages could exert a beneficial effect on one of the hallmarks of a group of neurodegenerative diseases, tau aggregation.
"For the next studies we will focus on other food-derived compounds, in particular those typical of the Mediterranean diet as not many studies have been conducted on tau protein."
These findings underscore the potential of investigating everyday dietary components for their health-promoting properties.
