Positive Health Online

Abstract

GRIFFITHS and VERNOTICA, Department of Psychiatry, Behavioral Pharmacology Research Unit, Johns Hopkins University School of Medicine, Baltimore, MD 21224, USA. rgriff@jhmi.edu investigated whether caffeine acts as a flavouring agent in cola soft drinks?

Background

Concern has been expressed about the nutrition and health impact of high rates of soft drink consumption. Caffeine is an added ingredient in approximately 70% of soft drinks consumed in the United States. The soft drink manufacturers' justification to regulatory agencies and the public for adding caffeine to soft drinks is that caffeine is a flavouring agent.

Methodology

A double-blind crossover study ran from November 1998 until the end of July 1999. The setting was an academic research centre. Twenty-five adult regular consumers of cola soft drinks were all able to detect a flavour difference between cola containing sugar and diet cola. A sensitive version of a forced-choice flavour-detection procedure was used to evaluate the effects of a wide range of caffeine concentrations (range, 0.05-1.6 mg/mL) on the ability to detect flavour differences between caffeinated and caffeine-free cola beverages. Repeated tests permitted determination of significant detection at each concentration in individual subjects. Percentage of subjects significantly detecting a flavour difference and mean percentage of trials correct at each caffeine concentration.

Results

Detection of flavour differences increased as a function of caffeine concentration. At the 0.1-mg/mL concentration, which is the approximate concentration in the majority of cola soft drink products, 2 subjects (8%) significantly detected a flavour difference and the mean percentage correct (53%) was at chance levels.

Conclusion

The finding that only 8% of a group of regular cola soft drink consumers could detect the effect of the caffeine concentration found in most cola soft drinks is at variance with the claim made by soft drink manufacturers that caffeine is added to soft drinks because it plays an integral role in the flavour profile. It is valuable for the general public, the medical community, and regulatory agencies to recognize that the high rates of consumption of caffeinated soft drinks more likely reflect the mood-altering and physical dependence-producing effects of caffeine as a central nervous system-active drug than its subtle effects as a flavouring agent.

References

Griffiths RR, Vernotica EM. Is caffeine a flavouring agent in cola soft drinks? Archives in Family Medicine 9(8): 727-34. Aug 2000.