Coffee & Health
Mental performance

Body of research supports the role of coffee consumption in mental performance

October 30, 2014

A segment on the BBC documentary, ‘Trust Me I’m A Doctor’, has explored the role caffeine may play in alertness. The feature suggests that using caffeine as a stimulant is ineffective and may lead to the development of dependency. ISIC is surprised by these conclusions, given the wealth of positive science on coffee and alertness.

Research to date supports the beneficial effect of caffeinated coffee on mental performanceand this has been confirmed by EFSA, which states that a cause and effect relationship has been established between a 75mg serving of caffeine (the amount in approximately one regular cup of coffee) and both increased attention and alertness, mainly in situations of low arousal or stimulation1.

Studies have also shown that drinking caffeinated coffee can help improve alertness and reduce errors in situations which require increased alertness. For instance, drinking caffeinated coffee can improve alertness and concentration during long distance driving2. During night work, caffeine has been shown to reduce errors and accidents by approximately 50% in workers drinking 2-3 cups of coffee3.

Furthermore, brain mapping technology indicates that caffeine is not linked to the brain circuit of dependence. This is supported by the fact that individuals do not develop a tolerance to the stimulant effects of caffeine4. The American Psychological Association also does not recognize caffeine as being an addictive substance5.

Most people will consume a level of caffeine they are comfortable with, however, for some people a high level of caffeine may lead to hyperactivity or anxiety. These effects are usually short lived once the individual returns to his/her regular pattern of consumption.

The BBC documentary also suggests that coffee consumption may lead to increased frequency of urination. Whilst pure caffeine may have a mild, short term diuretic effect, research suggests this is not strong enough to outweigh the benefits of fluid intake from coffee consumption6. Researcher Dr. Sophie Killer commented: “We found that consumption of a moderate intake of coffee – four cups per day, in regular coffee drinking males, caused no significant differences across a wide range of hydration indicators compared to the consumption of equal amounts of water. We conclude that advice provided in the public health domain, regarding coffee and dehydration, should be updated to reflect these findings.”

Current scientific evidence indicates that moderate coffee consumption (typically 3-5 cups per day) fits well with a healthy balanced diet and active lifestyle and may possibly be linked to a range of beneficial effects on health.

For more information on coffee and mental performance, please click here.


  1. EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA). (2011) Scientific Opinion on the substantiation of health claims related to caffeine and increased fat oxidation leading to a reduction in body fat mass (ID 735, 1484), increased energy expenditure leading to a reduction in body weight (ID 1487), increased alertness (ID 736, 1101, 1187, 1485, 1491, 2063, 2013) and increased attention (ID 736, 1485, 1491, 2375) pursuant to Article 13(1) of Regulation (EC) No 1924/20061. EFSA Journal,9(4):2054.
  2. Sharwood L.N. et al. (2013) Use of caffeinated substances and risk of crashes in long distance drivers of commercial vehicles: case control study. BMJ, 346:f1140.
  3. Smith A.P. (2005) Caffeine at work. Hum Psychopharmacol, 20:441-5.
  4. Nehlig A. et al. (2010) SPECT assessment of brain activation induced by caffeine: no effect on areas involved in dependence.Dialogues Clin Neurosci, 12:255-6363.
  5. American Psychiatric Association (2013) Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM V) ISBN 978-0-89042-554-1DSMV.
  6. Killer S.C., Blannin A.K. and Jeukendrup A.E. (2014). No evidence of dehydration with moderate daily coffee intake: a counterbalanced cross-over study in a free-living population, PLOS ONE.

More latest news

All news articles