A Hot Cup of Joe Sharpens the Mind

Caffeine may boost mental functioning in females slightly better than in males

/ Author:  / Reviewed by: Chris Galloway, M.D.

(RxWiki News) There’s nothing quite like a nice cup of coffee in the morning to get the mind going. But it may be that males and females experience the benefits of a caffeine boost differently.

A recent study tested the effects of caffeine on a group of children and adolescents that were asked to perform a series of mental functioning tasks.

The results found that caffeine helped the kids on memory and reaction time tasks. Gender differences were found between girls and boys on the tasks after they consumed caffeine.

"Don’t overdo it on caffeine."

Jennifer Temple, PhD, assistant professor and director of the Nutrition and Health Research Laboratory at the University at Buffalo, led a study to test the effects of caffeine on thinking and mental processing tasks.

“Caffeine is the most widely used stimulant in the world,” said the authors.

Previous studies have shown that caffeine use can enhance mental functioning involved with thinking and problem solving, according to the authors.

For this study, the researchers gave mental processing tests to a group of 96 children and adolescents before caffeine consumption and 60 minutes after having caffeine.

The boys and girls that participated were either too young to have hit puberty and old enough to have gone through puberty changes such as menstruation. Each participant was assigned to one of three caffeine groups.

The first group was given 1 milligram of caffeine per kilogram of weight. In other words, if a kid weighed 45 kg, which is about 99 lbs, they would consume 45 mg of caffeine. Many 12-ounce cans of soda contain around 50 mg of caffeine.

The second group was given 2 mg of caffeine for every kilogram of weight, meaning if the kid weighed 45 kg, they would consume 90 mg of caffeine.

The third group was given a fake dose, or placebo, of caffeine.

There were five mental processing tests in all, including a memory test, a reaction time test and the Stroop color word test.

The Stroop color word test uses different colored words that spell out different colors. The color of the actual word printed on the page and the color the word describes are different. For example, the word “purple” may be printed in yellow ink. The test taker has to focus intently to say purple, not yellow.

The results of the study showed that caffeine increased the number of correct answers on the memory test and improved responses in the reaction time.

The girls in the study did better than the boys on the Stroop color task, with more correct responses and faster reaction time.

Girls that had already been through puberty showed differences in reaction time on the stop and go task based on the part of the menstrual cycle they were in.

“This is the first study in children and adolescents to report sex differences in responses to caffeine on cognitive tasks as well as different responses according to the girls’ menstrual cycles. It suggests that if we look at caffeine as a model for illicit drugs, men and women respond differently because of circulating steroid hormones,” said Dr. Temple in a news release.

Dr. Temple’s intention for this research was to further understand the gender differences that may be present in addiction and how to tailor addiction treatments based on gender.

According to scientists at the Mayo Clinic, moderate caffeine consumption for a healthy adult is around 200 to 300 mg per day, which is roughly four cups of coffee. Mayo researchers suggest that drinking too much caffeine, more than 500 mg per day, can cause unpleasant side effects such as insomnia, upset stomach and muscle tremors.

This research was presented at the conference of the Federation of American Societies For Experimental Biology in Boston, MA, April 20-24, 2013. These study findings have not been published in a peer-reviewed journal.

The National Institute on Drug Abuse provided funding for this project. No conflicts of interest were reported.

Reviewed by: 
Review Date: 
April 22, 2013
Last Updated:
August 14, 2013