The thermic effect of sugar‐free Red Bull: Do the non‐caffeine bioactive ingredients in energy drinks play a role?

Abstract

Objective: Consumption of energy drinks is increasing amongst athletes and the general public. By virtue of their bioactive ingredients (including caffeine, taurine, glucuronolactone, and B-group vitamins) and paucity of calories, sugar-free "diet" versions of these drinks could be a useful aid for weight maintenance. Yet little is known about the acute influence of these drinks, and specifically the role of the cocktail of non-caffeine ingredients, on resting energy expenditure (REE) and substrate oxidation. Therefore, the metabolic impact of sugar-free Red Bull (sfRB) to a comparable amount of caffeine was compared. Methods: REE and respiratory quotient (RQ) were measured in eight healthy young men by ventilatedhood indirect calorimetry for 30 min baseline and 2 h following ingestion of 355 ml of either: sfRB 1 placebo, water 1 120 mg caffeine, or water 1 placebo, according to a randomized cross-over design. Results: sfRB and water 1 caffeine both increased REE to the same degree (14%). Additionally, sfRB briefly increased RQ. Water 1 caffeine had no effect on RQ relative to water 1 placebo. Conclusions: sfRB enhanced thermogenesis and marginally shifted RQ to favor carbohydrate oxidation. The stimulatory effects of sfRB on REE are mimicked by water 1 caffeine, indicating that the auxiliary ingredients do not influence this thermic effect. The metabolic effects of sfRB are primarily due to caffeine alone.

Effects of acute ingestion of a pre-workout dietary supplement with and without p-synephrine on resting energy expenditure, cognitive function and exercise performance

“…Analysis of AUC changes from baseline indicated that while PWS had a greater impact on VO 2 VCO 2 and RER values; the PWS + S observed greater changes from baseline compared to the PLA treatment. These findings are consistent with several reports indicating that ingestion of thermogenic type supplements increases energy metabolism and/or carbohydrate oxidation [33, 62, 66, 67] while contrasting other studies reporting either no effects [64] or greater fat oxidation [32]. However, ingestion of PWS + S treatment did not result in higher mean VO 2 values than the PWS treatment.…”

“…Campbell and coworkers [60] reported that ingestion of a supplement containing 200 mg of caffeine and green tea extract significantly increased resting metabolic rate from 7 to 9% for up to 3 h after ingestion. Moreover, Miles-Chan and colleagues [67] reported that consumption of a sugar free energy drink containing 120 mg of caffeine increased REE by about 4% and that the changes observed were due to the caffeine in the drinks rather than other nutrients (i.e., taurine and glucuronolactone).…”

Caffeine enhances activity thermogenesis and energy expenditure in rats

“…This is accompanied by an amplification of muscle thermogenesis, but only after 25 minutes of treadmill walking. This increase in calorie use may partly underlie the known ability of caffeine to induce weight loss or prevent weight gain in laboratory animals and promote negative energy balance in humans . Similar to the ability of caffeine to enhance athletic performance, the metabolic effects reported here may occur through multiple mechanisms, including elevated SERCA activity secondary to caffeine's increase of RYR‐induced sarcoplasmic reticulum Ca 2+ release.…”

“…Caffeine induces negative energy balance by altering multiple aspects of behaviour and metabolism, including physical activity, thermogenesis, and EE. 10,13,14,[28][29][30] Here, we demonstrate that caffeine enhances activity-related EE in rats, akin to NEAT in humans, even when physical activity is not changed (Figure 1). Specifically, caffeine significantly increased the caloric cost of treadmill walking by 8%.…”

The blood pressure-elevating effect of Red Bull energy drink is mimicked by caffeine but through different hemodynamic pathways

“…Each subject completed four separate experimental test days, according to a randomized crossover design, with at least a 2-day interval between any two test days. The concomitant metabolic response was measured in all subjects on each of the four test days, with the metabolic data for three of the four test substances previously published specifically in the context of the effect of sugarfree RB, and its potentially bioactive ingredients, on thermogenesis (Miles-Chan et al 2015). The study complied with the Helsinki Declaration of 1975 as revised in 1983 and was approved by the state ethical review board; all participants gave written consent.…”