Consuming a large amount of caffeine daily can inhibit the brain's ability to renew itself, according to an analysis of two interesting studies. Researchers from the Neuroengineering Research Center at Butler Hospital in Providence, Rhode Island, analyzed brain signals related to learning and memory in 20 individuals, revealing surprising details that challenge the assumption that "caffeine enhances plasticity."
Caffeine has a well-earned reputation for giving us a boost of alertness, thanks to its ability to block adenosine, a chemical in the brain that helps us feel sleepy at appropriate times. Adenosine also affects a process called long-term potentiation (LTP), which simply means how neurons in the brain strengthen connections with one another, believed to be crucial for the brain's ability to acquire new information and adapt over time.
A total of 16 individuals who drank between one to five caffeinated beverages daily, along with four individuals who hardly consumed caffeine, underwent a brain stimulation process designed to simulate the brain's readiness to learn, known as repetitive transcranial magnetic stimulation (rTMS). The team then looked for signs of electrical pulses in the nervous system as a means to measure LTP. For those who did not consume caffeinated beverages, the effects of LTP appeared significantly stronger.
According to the researchers, regular caffeine stimulation may cause an opposite effect in the brain, which could explain lower levels of plasticity, but this is still merely a hypothesis at this time. There are also warnings about having only 20 participants in this research. The review also relied on self-reported caffeine doses, meaning researchers cannot know how different doses of caffeinated beverages actually affect long-term plasticity.
However, the review was an experimental investigation aimed at enriching future hypotheses. The researchers intend to conduct further investigation through carefully controlled future studies, where the timing and dosage of caffeine consumption are strictly organized before testing. They say this would provide "a better estimate of the bioavailability in the central nervous system and its relation to plasticity responses." The researchers wrote, "A better understanding of how caffeine alters the underlying mechanisms of learning and memory, as well as the potential impact of caffeine on the effects of clinical rTMS, deserves more attention."
