Caffeine Consumption Impacts Genders Differently

Caffeine is a commonly used stimulant in coffee, soda, energy drinks, tea and chocolate. The effects of caffeine were studied in a group of adolescents in the age group of 12 to 17 years. The cardiovascular status and effect on intake of food was assessed after administration of various increasing doses of caffeine. The heart rate was found to decrease and diastolic blood pressure was seen to increase. Caffeine intake also promoted further consumption of high-calorie food.

Caffeine intake alters physiology and behavior in adults and adolescents. A modest intake of caffeine causes increased blood pressure, decreased heart rate and higher energy and concentration in adults. It affects the nervous system, causing anxiety, fidgeting, etc., at higher doses. These effects are seen not only in adults but also in children and teenagers. However, only a few studies have been done to describe the effects of caffeine in children. Therefore, this study was designed to assess the dose-related effects of caffeine on adolescent children and also to verify the difference in the way it influences boys and girls.

* The study was performed on 52 adolescents (26 male and 26 female) in the age group of 12 to 17 years. Based on their self-reports and analyses of their saliva for caffeine consumption, they were grouped into “low consumers” or “high consumers” of caffeine.
* The adolescents’ baseline heart rate and blood pressure were noted and they filled in a questionnaire containing a behavioral checklist.
* Next, participants consumed a given concentration of caffeine (0, 50, 100 or 200 mg) and had their heart rate and blood pressure measured every ten minutes over the next hour. After the hour, they filled in the above questionnaire again and ate from a variety of snacks provided to them.
* There were four such instances with different concentrations of caffeine each time for each participant. At the end of the four visits, height and weight of all the subjects were measured.

* Boys were found to consume more caffeine than the girls; and they justified the use for energy to get a rush or to boost athletic performance.
* Boys obtained their caffeine usually from energy drinks; as opposed to girls who got theirs from tea.
* The increase in diastolic blood pressure was related to the amount of caffeine consumed. On average, there was an increase by 6 mm Hg on consumption of 200 mg of caffeine. A decrease in heart rate was also seen with increased caffeine levels.
* More caffeine intake was associated with consumption of more intake of food high in calories, fat and protein. Also, girls had more dairy products when they had more caffeine, while boys had less.

The recruitment of “high-caffeine” consumers was less in this study; the researchers worry that they may have neglected the most relevant consumers. There were also more boys in the high-caffeine group than girls. The study had a small number of participants and were mostly upper-middle class Caucasians. Thus generalization of the results is not possible. Finally, it is possible that some of the participants may have been aware of the alterations in the drink they had to take during each visit, thereby negating the blinded effect of the study.

The study authors claim that this was the first study not only to highlight gender differences in the effects of caffeine in adolescents, but also to point out the differences in sources of caffeine and the impulses that drive caffeine consumption in girls and boys. The effects of caffeine on blood pressure in adolescents were found to be similar to those in adults. As caffeine was seen to increase high-energy food consumption, it is necessary to investigate the impact of caffeine further. Similar studies like this could help uncover the hidden physiology beneath gender-based effects in various other drug responses.

For More Information:
Effects of Acute Caffeine Administration on Adolescents
Publication Journal: Experimental and Clinical Psychopharmacology, 2010
By Jennifer L. Temple; Amber M. Dewey; University at Buffalo, New York

*FYI Living Lab Reports Are Summaries of the Original Research.

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