Evaluation of Caffeinated Beverages Sold in a National Sample of US Middle and High Schools

Abstract

Background: According to recommendations, adolescents should limit caffeine intake to no more than 100 mg/d. High schools (but not middle or elementary schools) participating in the US Department of Agriculture National School Lunch Program and School Breakfast Program are allowed to sell beverages with added caffeine to students, but the amount of caffeine is not regulated. The prevalence of caffeinated beverages sold to students and the amount of caffeine these beverages contain are unknown.

Objective: To determine the prevalence and types of caffeinated beverages in US middle and high schools, the amount of caffeine, and whether caffeinated beverage availability and caffeine content varied by school characteristics.

Design: Cross-sectional.

Participants/setting: A national sample of 45 middle schools and 45 high schools.

Main outcome measures: The amount of caffeine (in milligrams) per item, determined from manufacturer websites and photographs of ingredient labels for all products sold in schools.

Statistical analyses performed: Descriptive statistics and 2-sample t tests were used to examine average caffeine levels. Multivariate analyses examined whether caffeinated beverage availability and caffeine amounts varied by school demographics using multilevel mixed-effects logistic and linear regression models, with random intercepts for school district and schools nested within districts.

Results: More than half (55.6% [n = 25]) of high schools and 4.4% (n = 2) of middle schools sold caffeinated beverages. On average, caffeinated beverages contained 63 mg of caffeine. The most common caffeinated beverages were sodas, but coffee (103 ± 25 mg) and energy drinks (95 ± 14 mg) contained the highest caffeine levels. High schools had a significantly higher odds of selling caffeinated beverages than middle schools (odds ratio, 18.30; P < .01). Beverages were predicted to be 14 mg higher in caffeine in high schools than in middle schools (β = 13.88; P < .01).

Conclusions: There is widespread availability of caffeinated beverages in US high schools. The US Department of Agriculture could consider setting caffeine limits for beverages sold in schools to ensure students do not exceed 100 mg of caffeine daily.

Keywords: Caffeine; Competitive foods; Nutrition; School policy; Smart Snacks.