Consuming a large amount of caffeine each day could slow the brain’s ability to rewire itself, according to an analysis of two small but intriguing studies.
Researchers at the Neuromodulation Research Center at Butler Hospital in Providence, Rhode Island, analyzed brain signals associated with learning and storing memories in 20 people, uncovering surprising details that challenge assumptions that caffeine promotes plasticity.
“These preliminary data highlight the need to directly test the effects of caffeine in well-powered prospective studies, because in theory, they suggest that chronic caffeine use could limit learning or plasticity,” the researchers write in their published paper.
Thanks to its ability to block adenosine, a signaling chemical in the brain that helps us feel sleepy at the right time, caffeine is reputed to increase our alertness.
Adenosine also affects a process called long-term potentiation (LTP), which in simple terms is how neuronal cells in the brain strengthen connections with each other, which is thought to be crucial for the brain to take in new information and adapt successfully. time.
A total of 16 people who drank between one and five caffeinated drinks a day and four people who barely touched caffeine were subjected to a brain stimulation process designed to mimic the brain’s readiness to learn, called repetitive transcranial magnetic stimulation, or rTMS.
The team then looked for signs of electrical impulses in the nervous system as a way to measure LTP. In those who did not drink caffeinated beverages, these LTP effects appeared to be significantly stronger.
According to the researchers, regular stimulation with caffeine can cause an opposite effect in the brain, which could explain the lower levels of plasticity, but at the moment this is only a hypothesis.
There are some caveats: only 20 people participated in this research and the division between caffeine and non-caffeine was heavily weighted. The review also relied on self-reported caffeine doses, meaning researchers can’t know how different doses of caffeinated beverages actually impact long-term potentiation.
That said, the review was a pilot investigation intended to inform future hypotheses. He The researchers intend to investigate further with precise and well-controlled future studies in which the timing of caffeine intake and its dosage are strictly regulated before testing. This, the authors say, would provide “a better estimate of central nervous system bioavailability and correlation with plasticity responses.”
The relationship between caffeine and health is already complicated enough: It has been shown to have both positive and negative effects in previous research, from potentially protecting against dementia to perhaps increasing the risk of diabetes.
“A better understanding of how caffeine alters the underlying mechanism of learning and memory, as well as the potential impact of caffeine on the clinical effects of rTMS, deserves further attention,” the researchers write.
The research has been published in Frontiers in psychiatry.