Coffee is the best-known delivery system for caffeine, but this mildly addictive stimulant is also found in soft drinks, tea, chocolate and some pain medications. Caffeine acts on the central nervous system by triggering production of adrenaline, thereby speeding up the metabolism. Studies into caffeine's effects on the nervous system's most sophisticated processes -- brain function -- have yielded conflicting results. Some suggest that it improves learning ability; others say you're better off taking an afternoon nap.
Prevents Cognitive Decline
In May 2010, 22 scientific studies investigating the effects of caffeine on brain function were published in a special supplement to the "Journal of Alzheimer's Disease." Summarizing key findings, researchers listed "multiple beneficial effects," including "substantial" evidence of caffeine's protective role against Alzheimer's disease, dementia and Parkinson's disease. Not only does caffeine help prevent age-related cognitive decline and brain degeneration from plaque deposits, it also acts as a mood normalizer to counteract the depression common among people with Alzheimer's disease, researchers wrote.
Effects of Withdrawal
The BBC maintains that the problem with many caffeine studies is lack of clarity about whether coffee actually improves cognitive performance -- or merely appears to. The befuddlement of coffee drinkers before they've had their morning cup might not be impairment at all, notes the BBC, but a withdrawal symptom. To test this theory, in June 2011 the BBC imposed decaf on a self-confessed caffeine addict for seven days. For the first few days, he experienced tremors, reduced alertness and delayed reaction times. By the end of the week, though, all these withdrawal symptoms had cleared up and his performance was back to the same level it had been when he was drinking coffee. The BBC's conclusion: "Once we've recovered from coffee, we can do just as well without it."
Napping Trumps Caffeine
Students who believe that using coffee to help them stay awake all night cramming for exams should take heed of a study conducted by the University of California at San Diego, published in November 2008 in "Behavioral Brain Research." One morning, investigators gave 61 people the same learning tasks, then divided them into three groups. In the afternoon, one group napped for 60 to 90 minutes; another listened to a book on tape; and members of the third took a pill that either contained the caffeine equivalent of a large cup of coffee or a placebo. When tested, both the nappers and the placebo group had better recall of what they'd learned than their caffeinated co-participants.
Men vs. Women
A U.K. study to examine how caffeine affects people in high-stress situations yielded surprisingly gender-specific results. For the experiment, researchers divided 64 people into same-sex pairs close in age. Everyone believed that they had to make a public presentation of the results of a series of tests, puzzles and tasks. After scores on a range of cognitive, emotional and physical reactions were tallied, the authors concluded that caffeinated women had managed stress more effectively than their male counterparts, who were less confident and took longer to complete tasks. One possible flaw in this study published in the December 2010 "Journal of Applied Social Psychology": maybe the women would also have outperformed the men without caffeine.
References
- Mayo Clinic: Nutrition and Healthy Eating
- National Institute of Mental Health; Caffeine No Substitute for Nap to Enhance Memory; Dec. 8, 2008
- BBC Science and Nature; Caffeine and the Brain: Does Caffeine Give Us a Mental Edge?; June 17, 2011
- News Medical; Caffeine Normalizes Brain Function and Prevents Cognitive Decline; May 18, 2010
- Food Product Design; Caffeine Boosts Women's Brain Function; Feb. 7, 2011
- "Journal of Applied Social Psychology"; Abstract; Interactive Effects of Caffeine Consumption and Stressful...; L. St. Claire, et al.; December 2010
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