Energy drinks (ED) have increased in popularity among adolescents and young adults, because of the possible ergogenic effects [
Taurine (aminoethane sulfonic acid) is a ubiquitous compound found in very high concentrations in heart and muscle. It has been demonstrated that it has a role in the control mechanism of myocardial contractility and studies in animal models have shown that the lack of taurine induces the onset of dilated cardiomyopathy; the beneficial effect of taurine on heart failure was also reported [
The aim of this study was to investigate whether taking a taurine and caffeine containing energy drink determines acute changes in myocardial function assessed by conventional echo-Doppler analysis and by speckle tracking echocardiography (STE), a new technique for assessing myocardial function [
The study group included 35 healthy young volunteers (mean age
Study population
Age |
|
Gender (% female) | 17 (48.6%) |
Weight (Kg) |
|
High (cm) |
|
Body surface area (m2) |
|
Drink (mL) |
|
Usual drinker (%) | 8 (22.9%) |
Current smoker (%) | 10 (28.6%) |
Physical activity (%) | 6 (17%) |
All participants were asked to abstain from smoking, coffee, and other food or beverages containing caffeine for at least 12 hours before the examinations. All the examinations were carried out in the afternoon between meals. Baseline clinical, blood pressure, ECG, and echocardiographic measurements were made after 5 minutes of supine rest in a quiet and comfortable environment. After baseline examination, all subjects drank 168 mL/m2 (BSA, Gehan & George) of an energy drink containing caffeine (0.03%), taurine (0.4%), glucuronolactone (0.24%), glucose, and other ingredients, in maximum 5 minutes, and they underwent again echocardiography, electrocardiography, and blood pressure measurements 1 hour after drinking. Each participant was also studied in a control experiment by an equal volume of fruit juice one day after energy drink consumption.
The analysis of files recorded was performed offline by a single, experienced, and independent echocardiographer, who did not know if the images refer to those obtained at baseline, after energy drink, or fruit juice consumption, using a commercially available, semiautomated, 2-dimensional strain software (EchoPac, GE, Milwaukee, WI, USA). The study protocol was in accordance with the Helsinki Declaration and the ethical standards of our institution, and all participants gave informed consent for participation in the study.
Echocardiographic studies were performed using a high-quality ultrasound machine (Vivid 7; GE, Milwaukee, WI) with the subjects in the left lateral recumbent position. All measurements were made in accordance with current recommendations of American Society of Echocardiography (ASE) [
Left ventricle (LV) systolic function was analyzed by calculating left ventricle ejection fraction (LVEF), measured using Simpson’s method, and by obtaining left ventricle longitudinal function parameters, as mitral annular systolic plane systolic excursion (MAPSE) with M-mode and mean peak systolic annular velocity with pulsed tissue-Doppler (mitral
Right ventricle (RV) systolic function was assessed by calculating tricuspid annular plane systolic excursion (TAPSE) and mean peak systolic annular velocity by pulsed tissue Doppler on tricuspid annulus (tricuspid
The speckle-tracking analysis was performed in accordance with the indications of the ASE/EAE consensus document of Mor-Avi et al. [
Data are reported as mean ± SD. Changes in the variables observed after ED and fruit juice consumption were compared using the Student’s
All the variables at baseline and after taking ED are shown in Table
Clinical and echocardiographic data after energy drink assumption
Baseline | Energy drink | Relative change % |
|
|
---|---|---|---|---|
HR (bpm) |
|
|
1 | 0.69 |
SBP (mmHg) |
|
|
3 | 0.35 |
DBP (mmHg) |
|
|
6 | 0.07 |
LVEF (%) |
|
|
5 | 0.01 |
Aortic CW (m/s) |
|
|
9 | 0.01 |
MAPSE (mm) |
|
|
11 | <0.001 |
TAPSE (mm) |
|
|
15 | <0.0001 |
GLS (%) |
|
|
10 | 0.004 |
LA global PALS (%) |
|
|
3 | 0.41 |
RA global PALS (%) |
|
|
2 | 0.54 |
Global RVLS (%) |
|
|
8 | 0.001 |
Free wall RVLS (%) |
|
|
5 | 0.01 |
LV twisting (degrees) |
|
|
22 | <0.0001 |
Mitral |
|
|
0 | 0.8 |
Mitral |
|
|
2 | 0.46 |
Mitral |
|
|
0 | 0.33 |
Mitral |
|
|
0 | 0.94 |
Mitral |
|
|
0 | 0.80 |
Mitral |
|
|
4 | 0.21 |
Tric |
|
|
0 | 0.71 |
Tric |
|
|
0 | 0.66 |
Tric |
|
|
0 | 0.88 |
HR: heart rate; SBP: systolic blood pressure; DBP: diastolic blood pressure; EF: ejection fraction; LV: left ventricle; RV: right ventricle; LA: left atrium; RA: right atrium;
Clinical and echocardiographic data after fruit juice assumption
Baseline | Fruit juice | Relative change % |
|
|
---|---|---|---|---|
HR (bpm) |
|
67.8 ± 10.6 | 1 | 0.84 |
SBP (mmHg) |
|
|
1 | 0.83 |
DBP (mmHg) |
|
|
2 | 0.38 |
LVEF (%) |
|
|
1 | 0.61 |
Aortic CW (m/s) |
|
|
0 | 0.78 |
MAPSE (mm) |
|
|
1 | 0.40 |
TAPSE (mm) |
|
|
4 | 0.18 |
GLS (%) |
|
|
2 | 0.36 |
LA global PALS (%) |
|
|
4 | 0.52 |
RA global PALS (%) |
|
|
3 | 0.70 |
Global RVLS (%) |
|
|
3 | 0.53 |
Free wall RVLS (%) |
|
|
1 | 0.60 |
LV twisting (degrees) |
|
|
0 | 0.14 |
Mitral |
|
|
0 | 0.75 |
Mitral |
|
|
2 | 0.74 |
Mitral |
|
|
0 | 0.50 |
Mitral |
|
|
0 | 0.18 |
Mitral |
|
|
0 | 0.40 |
Mitral |
|
|
5 | 0.50 |
Tric |
|
|
0 | 0.74 |
Tric |
|
|
0 | 0.59 |
Tric |
|
|
0 | 0.74 |
HR: heart rate; SBP: systolic blood pressure; DBP: diastolic blood pressure; EF: ejection fraction; LV: left ventricle; RV: right ventricle; LA: left atrium; RA: right atrium;
Mean relative increase from baseline. HR: heart rate; SBP: systolic blood pressure; DBP: diastolic blood pressure; LVEF: left ventricular ejection fraction; MAPSE: mitral annual plane systolic excursion; TAPSE: tricuspid annular plane systolic excursion; GLS: left ventricular global longitudinal strain; RVLS: right ventricular longitudinal strain; PALS: peak atrial longitudinal strain. *Significant versus control (fruit juice). For
Left ventricular twisting at baseline and after energy drink (ED) consumption.
Free wall right ventricular longitudinal strain (RVLS) at baseline and after energy drink (ED) consumption.
In addition to standard echo-Doppler analysis, speckle tracking echocardiography (STE) was used in our study to assess cardiac deformation in three spatial directions: longitudinal, radial, and circumferential. STE is a new technique for assessing myocardial function in physiological and pathological settings, and its feasibility and accuracy were tested in comparison with tagged magnetic resonance imaging, the gold standard to study myocardial deformation. It has been proved that STE is able to detect initial ventricular dysfunction in hypertension, diabetes, valvular heart disease, and heart failure, with high sensitivity in analyzing minimal change in myocardial deformation [
In our study population of 35 young healthy subjects, taking an ED containing sugar, caffeine (0.03%), and taurine (0.4%) showed a significant change of myocardial function of both LV and RV one hour after drinking it, suggesting a possible positive effect on cardiac inotropism.
In fact, the study of LV performance showed an increase of longitudinal function, with an increase of MAPSE and GLS, and a remarkable enhancement of LV Twisting (Figure
Likewise, the study of RV performance showed an improvement of longitudinal function with a significant increase of TAPSE, and global and free RVLS in respect to baseline (Figure
Such modifications on cardiac mechanics are probably due to the inotropic effect of some substances contained in the ED.
In particular, taurine seems to have a similar digital effect by means of the control of myocardial contractility, modulating sarcoplasmic reticular Ca2+ release, and stimulating the pumping rate of Ca2+ activate ATPase pumps [
In fact, it has been reported that taurine may reduce left ventricular end-diastolic pressure in patients with heart failure [
In normal subjects, LV twist represents a mechanism for generating stored energy during systole, which is released during early diastole to produce ventricular recoil, upward annular motion, and suction, confirming the close relation of systolic function to early diastole [
The LV twisting motion is a consequence of myocardial fiber orientation, which changes from an approximately longitudinal but slightly oblique orientation in the subendocardium to a circumferential orientation in the mid-wall and to an oblique orientation in the subepicardium [
Previous studies have found that in the setting of LV diastolic dysfunction, torsion is increased in patients with mild diastolic dysfunction but reduced in those with more severe degrees of diastolic dysfunction [
Moreover, Tan et al. [
Since this study was performed on young healthy individuals at rest, future studies need to focus on whether such benefits persist after long term consumption of energy drinks and what the effects are of consuming these drinks during physical activity; it will also be important to determine which of the effects are induced in patients with cardiac disease to further our understanding of the potential benefits or risks of energy drink consumption.
Some limitations should be considered in this study. We evaluated young healthy subjects, so these results cannot be generalized for other populations. The number of subjects of our sample was limited, although it has allowed us to reach interesting conclusions. Moreover, we have investigated the acute changes on myocardial performance only one hour after energy drink consumption. Based on the pharmacokinetics of certain substances of this drink (such as caffeine and taurine), it should be interesting to evaluate the cardiovascular effect at different times from the consumption of these beverages. Lastly, we have used a pear juice as a control, but the same volume of this beverage does not correspond to the same amount of sugar dissolved in the energy drink.