11 March, 2014
From VOA Learning English, this is the Health Report.
Many people say they cannot start their day without first having a cup of coffee or tea. People say these drinks help them think clearly and feel more awake. This is because of caffeine, a substance found in some plants. Caffeine helps to give a jump start to the nervous system.
Now, a report says it may also improve long-term memory. The report was published earlier this year in the journal Nature Neuroscience.
Mike Yassa is a neurobiology professor at the University of California, Irvine. He and other researchers wanted to know if caffeine could improve what they called memory consolidation.
They asked a group of individuals to learn something new. Then, the same people were given caffeine, the active ingredient in coffee, tea and chocolate. Professor Yassa explains.
"So after you learn anything, it takes some time for that memory to strengthen and become resistant to forgetting. And over the first 24 hours is actually where most of the forgetting happens. So that is where we wanted to intervene with caffeine and see if we can help reduce this forgetting to some extent."
He and the other researchers worked with a group of 160 people who were caffeine-free. On the first day, all the subjects were shown pictures of everyday objects. They were asked to identify whether the pictures could be found inside the house or outdoors. Some of the subjects were then given a caffeine pill. The others were given a placebo - a pill containing an inactive substance.
On the second day, all of the subjects were asked to look at more pictures. Some of the images were exactly like the ones they had seen 24 hours early. But other images were different. And a third group of pictures was similar to the first group but a little different. The participants had to decide whether the images they saw were the same or different from the ones on the first day.
Professor Yassa says their answers helped to show the effects of caffeine on memory.
"When they actually had to make a memory judgment and say, 'Is this the same item I have seen before or not?' that was a really important bit of information for us. And we find that if they are on caffeine they are much more likely to make the right decision."
He says those who took the caffeine pills had a ten to twelve percent increase in their ability to remember the objects. The amount of caffeine the researchers used in the study was similar to one strong cup of coffee.
Professor Yassa says pills with a little more coffeine also increased memory, but resulted in some participants appearing more nervous.
And that's the Health Report from VOA Learning English. For more stories about health, go to our website 51voa.com. I'm Christopher Cruise.