Put on the coffee. Brew some tea. Here's another good reason to enjoy a cup of java daily: A new study suggests that caffeine may play a role in enhancing memory.
There are many ways people consume caffeine, including in coffee, tea, soda and chocolate, says the study's lead author Michael Yassa. It doesn't matter what the source is, the effect of caffeine will likely be the same, he says.
Yassa and colleagues at Johns Hopkins University recruited 160 young, healthy participants, who did not regularly consume caffeinated products. The participants studied a series of images, then five minutes later, took either 200 milligrams of caffeine in tablet form, about the amount of caffeine in a strong cup of coffee, or a placebo.
The next day, participants were asked to identify images they had seen the day before. Some images were new, and some were similar but not exactly the same. For example, if they were shown a picture of a yellow rubber duck originally, the next day, it was a picture of a rubber duck that was shorter and thicker, says Yassa, who was at Johns Hopkins when the study was conducted but now is an assistant professor of neurobiology and behavior at the University of California-Irvine.
Findings published in the journal Nature Neuroscience: The people who consumed caffeine were more likely to correctly identify the similar items as slightly different from the original picture. The brain's ability to recognize the difference between two similar but not identical items reflects a deep level of memory discrimination, Yassa says.
Another example of pattern separation is remembering where one's car is parked today vs. yesterday, he says. "This type of discrimination is involved in every facet of memory," Yassa says.
The researchers also had participants consume 100 milligrams and 300 milligrams of caffeine and found 100 milligrams was not effective at getting the memory boost, Yassa says. The 300-milligrams dose was no more effective than 200 milligrams, and at the higher amount, people started to report some side effects such as headaches and feeling jittery, he says. "The 200-milligram might be the most optimal dose to get this memory boost."
One strong cup of coffee might contain 200 milligrams of caffeine, he says. A typical espresso has 80 milligrams, so a double-shot latte will have 160 milligrams, he says.
Other research has found that low doses of caffeine have beneficial effects on attention and focus, Yassa says. A few studies on caffeine's effect on humans have found little or no effect on long-term memory retention, but numerous studies in animals have shown that caffeine has a beneficial effect, he says.
While this study is encouraging, he cautions that high doses of caffeine can have negative effects, such as anxiety, increased heart rate, increased blood pressure and headaches. "I'm not going to stop drinking my coffee, but it's important to be aware of the costs and benefits," he says. "Drinking coffee late at night is not going to be helpful for most people."
Registered dietitian Elisa Zied, author of Younger Next Week, says, "The bottom line when it comes to coffee and caffeine intake is that they definitely have their perks, but for some they can have their perils, too. Studies on the possible health benefits related to coffee/caffeine intake will continue to emerge, so no one study should dictate a personal decision to include or exclude it from their diet."