You rely on your morning java jolt to zap you awake, but you have probably not been aware that your cup of coffee also has memory enhancing properties. That is what a recent study has found — in addition to its other health benefits, caffeine can give your memory a serious boost.

“We've always known that caffeine has cognitive-enhancing effects, but its particular effects on strengthening memories and making them resistant to forgetting has never been examined in detail in humans,” Michael Yassa, one of the authors, told TheDoctor.

People who had had caffeine were better able to correctly identify the slightly different images as ‘similar’ to previously viewed images, rather than incorrectly identifying them as the same, suggesting they remembered them more clearly.

Study participants did not regularly consume caffeine-containing products such as coffee. Five minutes after studying a series of images of everyday items such as a rubber duck or a coffee mug, they were given either a 200-milligram caffeine tablet or a Placebo. To measure participants’ caffeine levels, the investigators took samples of their saliva before they took the tablets, and again one, three, and 24 hours afterwards.

The next day, both the caffeine and placebo groups were tested on their ability to recognize the images that they were shown the day before. Some of the images were the same as from the day before; some were completely new; and some were similar but slightly different from the previously viewed items.

People who were given caffeine were better able to correctly identify the slightly different images as "similar" to previously viewed images, rather than incorrectly identifying them as the same. That ability, said Yassa, “suggested to us that they had a much more detailed record of what they learned the day before.”

Yassa, an assistant professor in the Department of Neurobiology and Behavior at the University of California, Irvine said that the findings were surprising.

“We had always known that caffeine has enhancing effects on other cognitive functions such as attention, alertness, focus, and vigilance. But we wanted to focus specifically on memory, and we didn’t know what to expect, because past studies in humans have not been able to parse out this effect from other cognitive effects.”

Since they administered caffeine after the participants had viewed the images on the first day, the researchers, from Johns Hopkins University as well as UC Irvine, were sure the improvement was due to caffeine's effects on memory rather than from attention, vigilance, focus, or other factors.

“By administering caffeine after the experiment, we rule out all of these effects and make sure that if there is an enhancement, it's due to memory and nothing else,” said Yassa. “That way, the only thing caffeine could have enhanced was the storage process, the process strengthening those memories so that they don’t become degraded or forgotten.”

The researchers plan to follow up with brain imaging to study the mechanisms by which caffeine has this memory-enhancing effect.

“Our next step is to put people in an MRI scanner and give them the same task while they are on caffeine or on placebo, and observe activity in the different regions in the brain that are associated with learning and memory to see if there is enhancement there,” Yassa said.

The study is published in Nature Neurobiology.