A new study from Johns Hopkins University has proven for the first time that caffeine consolidates and preserves long-term memory.
It has long been known that a little caffeine ramps up concentration, attention, vigilance, visuospatial reasoning, and the ability to perform calculations and think logically. It has also been recognized that caffeine improves short-term memory, for example, remembering a telephone number you have just looked at before you dial it. In addition, caffeine has been shown to improve the sometimes declining memories of older people. However, until this study was completed, no one knew if caffeine’s benefits to mental processes extended to boosting long-term memory in people of all ages.
The New Study
To conduct this study, researchers picked over 150 volunteers who did not usually consume much caffeine. The volunteers were asked to study pictures of flowers, musical instruments, and other objects. After the participants viewed the pictures, the scientists gave half of them a pill containing either 100mg, 200mg, or 300mg of caffeine–-the amount found in a 4oz, an 8oz, or a 12oz cup of filter-drip coffee—and gave the other half an identical looking placebo. Neither the subjects nor the researchers knew until the study ended who had taken caffeine and who had taken the placebo.
The next day, researchers showed the volunteers more pictures, asking the volunteers if these pictures were the same, different, or different but similar to the pictures they had been shown the day before. The subjects who had been given 200mg caffeine pills performed significantly better at spotting and identifying pictures similar to the ones they had seen the previous day than did the subjects who had been given a placebo. In further tests, the researchers discovered that less than 200mg of caffeine conferred little or no benefit, while 300mg did not improve memory performance any more than the 200mg had done. (“Post-study caffeine administration enhances memory consolidation in humans,” Nature Neuroscience, Daniel Borota, et al., January 12, 2014.)
Building Brain Connections to Help You Remember
How can caffeine help us to improve our ability to preserve and retrieve memories? A section of the brain called the “hippocampus” is responsible for maintaining long-term memory. Decades ago, researchers at the Weisman Institute in Israel discovered the astonishing fact that caffeine causes dendritic spines, the branching extensions at the ends of nerve cells that allow them to make synaptic connections with each other, to grow longer and even caused new spines and branches to develop as well (“Release of calcium from stores alters the morphology of dendritic spines in cultured hippocampal neurons,” Proceedings of the National Academy of Science, E. Korkotian and M. Segal, US, 96:12068-72, 1999). The recent Johns Hopkins study provides the first direct evidence that this proliferation of dendrites actually does improve long-term memory in human beings. This study demonstrates that caffeine is the only known substance that can augment brain functions by altering the physical structure of the brain.
Modest Amounts of Caffeine Work Best
Modest amounts of caffeine do the most. If you take more than you need, the benefit for long-term memory is eroded. So how much caffeine is best for memory consolidation? It turns out that, for many people, about 200mg of caffeine, the amount in an 8oz cup of filter-drip coffee, is excellent for cementing your memories. Up to 300mg seems to do even more; but, as we said, significantly more than this may actually start to reverse the memory benefits. However, remember that caffeine sensitivity and the way caffeine is metabolized varies widely. Some people will do better with much less caffeine, while others do better with considerably more. For example, genetic predispositions dramatically alter the effects of identical amounts of caffeine on different people. Therefore, the only way to really know how much caffeine you should take is by trying caffeine for yourself and seeing how you do and how you feel.
How to Get Your Caffeine Memory Boost
An 8oz cup of filter-drip coffee, containing about 200mg of caffeine is a good source of caffeine to help your memory. Some people may even prefer a 200mg caffeine tablet. Other sources of caffeine can provide the same benefit.
Below is a list of the approximate amounts of caffeine in some commonly consumed products:
- Arabica filter-drip coffee (8oz): 200mg
- Robusta filter-drip coffee (8oz): 400mg
- Dark chocolate bar (1.45oz): 31mg
- Soda (12oz): 40mg
- Diet soda (12oz): 45mg
- Energy drink (12oz): 115mg (on average)
- Black tea (6oz): 50mg
- Coffee ice cream (8oz): 60mg
(Note: Arabica coffee beans are better quality beans and have half the caffeine of harsher tasting Robusta coffee beans. You might want to know that Duncan Donuts and MacDonald’s use Arabica beans, while most coffee shops use Robusta beans.)
So, if you want to ramp up your memory, don’t forget caffeine!