Comparing the caffeine content of caffeine-containing dietary supplements in British Columbia

Abstract

Background and Purpose: The use of dietary supplements is on the rise in Canada. This raises questions about the safety of the supplements when taken in the recommended dosage. One ingredient of concern in dietary supplements is caffeine, which can cause adverse health effects when consumed in great enough quantities. Given the lack of research into the caffeine content of dietary supplements, along with few regulations that exist regarding labelling or limits on caffeine content within Canada, a major concern is whether or not these supplements pose a risk to the public. The purpose of this study is to compare the caffeine content of various types of dietary supplements, and to determine if the caffeine content warrants a risk to the public. Methods: Supplement stores within the Vancouver Metropolitan Area were visited online and in person, and supplements were categorized as an energy drink, pre-workout supplement, energy bar, fat-loss supplement, or caffeine pill or capsule. The caffeine content per recommended dosage of each supplement was recorded from the label. Results: It was found that the caffeine content did vary between supplement categories (Kruskall-Wallis one way ANOVA test had a p-value < 0.000), and that fat-loss supplements and pre-workout supplements had the highest caffeine content with a mean 221.19mg per serving and 249.68mg per serving respectively. Caffeine pills had a mean of 186.90mg per serving, energy drinks had a mean of 166.84mg per serving, and energy bars had a mean of 85.06mg per serving. Discussion: Health Canada recommends that healthy adults not exceed 400mg of caffeine per day. Exceeding this limit can lead to adverse health reactions, such as anxiety, insomnia, heart palpitations or more serious symptoms such as convulsions or death. It was found in this study that 5% of the samples exceeded 400mg, and can be considered hazardous. Taking multiple doses of supplements, or consuming additional caffeine from alternative sources, such as coffee, also puts consumers at a greater risk of exceeding the recommended limits. Currently there are no regulations in Canada regarding how much caffeine is permitted within these products, or any labeling requirements for caffeine in dietary supplements. Conclusion: Given the increase in popularity of dietary supplements in Canada, along with the limited regulations on labelling requirements, caffeine-containing supplements could potentially pose a risk to consumers. This study shows that the caffeine content differs between types of dietary supplements, and that some supplements exceed the Health Canada guidelines of 400mg. More regulations and guidelines on labeling requirements for these supplements may be necessary to protect the public.