According to researchers at Johns Hopkins University, consuming caffeine improves one’s long-term memory. The findings were recently published in the journal Nature Neuroscience. Investigators recruited 160 people ranging from 18 to 30 years in age. None of the participants consumed caffeine on a regular basis and all were in good health.
The subjects were asked to study a series of images and were then split into two groups. Five minutes after having seen the pictures one group was administered 200 milligrams of caffeine (in tablet form), while the other group was given a placebo pill. Researchers took saliva samples to determine the amount of caffeine present in the bodies of the participants. Samples were taken before the caffeine pills were administered and again in intervals of one, three and 24 hours afterwards.
The day after the participants were shown the pictures they were presented with a new set of images and were asked if they had seen any of the pictures the previous day. Those who had taken caffeine the day before performed better than the other group. Some of the images shown the day after the caffeine was consumed had only small differences relative to the original images. This illustrated that caffeine has a strong impact on memory, since small details were recalled. This ability to distinguish between similar yet different items is known as pattern separation. Since most memory loss occurs within 24 hours, recalling things beyond that time is a good indication that long-term memory is improved.
Researchers experimented with other doses besides 200 milligrams. A 100 milligram dose had no effect and doses of 300 milligrams or more were no better than 200 milligrams at improving memory. The higher doses proved to have some undesirable side effects, such as headaches or feeling jittery. Therefore the 200 milligram dose, which is about the same amount found in a strong cup of coffee, appears to be the ideal amount.
Of the few previous studies which examined the effect of caffeine on memory the influence of caffeine was found to be negligible; this study was different since many of the pictures used in the experiment had only small changes. In past studies images were used that were very different and therefore it would not have been known if participants were able to remember small changes. Michael Yassa, lead author of the study, said if his team had chosen to use a stand recognition memory task , void of the tricky similar items, the results would have found that caffeine had no effect.
Now that it has been determined that caffeine has an effect on memory, the next step is to find out exactly why. “We can use brain imaging techniques to address these questions“ says Yassa. Once the impact on the brain by caffeine has been more precisely determined, it may eventually help prevent or cure illnesses such as Alzheimer’s or dementia, where poor memory is one of the main symptoms. In the future patients may be able to take a type of caffeine pill to reverse the progression of these diseases.
A cup of coffee per day may have health benefits but too much caffeine is not good. Besides the previously mentioned side effects, high caffeine intake can also lead to tremors, insomnia and dizziness. Of course, coffee is not the only source of caffeine. Tea is a good alternative for those who don’t like coffee.
By Jean-Paul Gauthier