Energy drinks are promoted as enhancing behavioural outcomes by reversing fatigue effects and consequently increasing alertness and endurance (Heckman, Sherry, & de Mejia, 2010). Ingredients may include caffeine, taurine, glucuronolactone, sugars, and other B vitamins and herbal extracts. Despite the range of constituents, researchers generally claim caffeine as the core ingredient responsible for the stimulatory effects of energy drinks (Reissig, Strain, & Griffiths, 2009). However, recent research has suggested a synergistic interplay between energy drink constituents, with greater performance benefits conferred by the whole beverage than expected from the caffeine content alone (Marczinski et al., 2011 and Scholey and Kennedy, 2004). For example, Scholey and Kennedy (2004) reported that energy drink consumption improved performance on ‘secondary memory’ and ‘attentional speed’ factors relative to placebo, with no significant improvement in performance following independent caffeine ingestion. However, Scholey and Kennedy (2004) note that independent caffeine effects may have been detected with increased power, particularly in light of the small sample size used in this exploratory study (N = 20).
Consequently, further systematic analysis of the independent and interactive effects of energy drink constituents is required before conclusions are drawn regarding their relative efficacy. One core energy drink ingredient which lacks such scrutiny is taurine (2-aminoethane sulphonic acid), an abundant free amino acid widely-distributed throughout the body and readily found in animal-derived dietary sources (Finnegan, 2003 and Huxtable, 1992). Despite advertising claims of enhanced alertness post-energy drink consumption, and marketing of taurine as a key energy drink ingredient, there is a dearth of research regarding taurine’s behavioural impact (Australia New Zealand Food Authority, 2001 and Finnegan, 2003). Caffeinated taurine drink