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Short communication: in vitro assessment of erosive potential of energy drinks.


The consumption of the so-called energy drinks has increased considerably in Brazil and worldwide, mainly amongst young people and individuals engaged in sports activities, who are the main consumers [Carvalho et al., 2006]. Energy drinks have been developed to increase the physical resistance and the state of alertness, produce faster responses and greater concentration, avoid sleep, stimulate the metabolism, and help eliminate harmful substances from the body [Ballistreri and Corradi-Webster, 2008].

According to Brazilian law, energy drinks are identified as ready-to-use liquid compounds, composed of taurine, caffeine, glucoronolactone, inositol, and B-complex vitamins. Some also contain minerals and carnitine, among other substances, sugar at a concentration between 12 and 14% [Malinauskas et al., 2007]. Other formulations, however, are sugar-free. Several studies have demonstrated that the consumption of these energy beverages by young people and sports men and women range from 51% [Malinauskas et al., 2007] to 64.9% [Ballistreri and Corradi-Webster, 2008]. Due to this high consumption, Brazilian [Matumoto, 2008] and other researchers [Kitchens and Owens, 2007] have investigated the effects of energy drinks on dental enamel, as they have low pH [Ehlen et al., 2008]. The possible deleterious action of these drinks to enamel requires that dentists act preventively, alerting their at risk patients about the adverse effects that may be caused by their frequent use [Matumoto, 2008].

The total soluble solids content (TSSC) or degrees Brix ([degrees]Bx) is numerically equal to the percentage of sugar and other dissolved solids in a solution. This scale is used in the food industry for measuring the approximate amount of sugars in fruit juices and other beverages. Thus, a solution that is 25[degrees] Brix has 25g of sugar per 100g of solution. Sugars may be classified as reducing or non-reducing based on their reactivity with Fehling's reagent. Sugars that are unable to reduce the above oxidizing agents are called non-reducing sugars (e.g. sucrose).

In view of the high consumption of energy drinks among adolescents and sports people, as well as the lack of international studies addressing this subject, the purpose of this study was to evaluate in vitro the endogenous pH, the titratable acidity, the content of total soluble solids (TSSC) and the non-reducing sugars content in energy drinks.

Materials and Methods

Determination of endogenous pH, titratable acidity (TA), total soluble solids content (TSSC), and sugar levels was undertaken on samples of 9 commercial energy drinks as used in the city of Campina Grande, (Brazil). The products were randomly selected according to their market availability (Table 1). They were evaluated by a randomised experiment with 3 measurements for each sample, recording the mean of both values. Data were collected by a single calibrated examiner and were recorded on study-specific charts.

pH Measurement. The pH of each drink was determined using a pH meter (TEC-2 pH meter; Tecnal, Sion Paulo, SP, Brazil) placed directly into each solution. The pH meter was accurate to 0.1 and was first calibrated according to the manufacturer's instructions, employing buffer standards of pH 7 and pH 4. As much as 25 mL of each energy drink was placed in a beaker, the pH electrode was immersed into each drink and the reading recorded.

Titratable Acidity (TA). This was measured according to the method of the Association of Official Analytical Chemists [AOAC, 1995], that is, the amount of 0.1 N KOH solution needed for a product to reach a at or above neutral pH. A 10 mL aliquot of the diluted product was titrated (10% solution of the sample) with the 0.1 N KOH solution until the test substance reached a pH value between 8.2-8.4. Readings were taken using a pH meter (TEC-2R; Tecnal, Sao Paulo, SP, Brazil). When this value was reached, the spent KOH volume was recorded and the acidic percentage of the substance was calculated, and expressed as percentage of citric acid.

Total Soluble Solids Content (TSSC). The TSSC readings were made by refractometry using an Abbe refractometer (PZO-RL1, Warszawa, Poland). As the refractive index of a sugar-containing solution is also temperature-dependent, the refractometer was calibrated at 20[degrees]C, using deionised water (refraction index=1.3330 and 0[degrees] Brix at 20[degrees]C) and the readings taken.

Non-Reducing Sugars. Non-reducing sugars (e.g.: sucrose) was measured according to the method of Association of Official Analytical Chemists [AOAC, 1995] and the results were expressed as percentages. Non-reducing sugars were estimated by subtracting reducing sugars from total sugars and multiplying this value by the conversion factor of glucose in sucrose (0.95).

Statistical analysis. The mean values and standard deviation were analyzed statistically using the SPSS statistical software (SPSS Inc., Chicago, IL, USA).


The results of the physical and chemical parameters varied among the evaluated brands of energy drinks. Table 2 displays the distribution of pH; TA, TSSC and mean sugars values for the tested energy drinks. All energy drinks showed pH below a critical value of 5.5 and values ranged from 1.52 (Flash Power) to 3.20 (Red Bull). The lowest TA value was recorded for 220V (0.56) and the highest was for Bad Boy Power Drink (1.04). Flying Horse Light presented the lowest TSSC (1.7%), while Flying Horse the highest TSSC (12.6%). With regards to non-reducing sugars, the values ranged from 0.00 (Red Bull Sugarfree and Flying Horse Light) to 54.3 (Flying Horse). Five samples presented sugar content over 30 g per 100 mL.


Since the introduction of Red Bull in Austria (1987) and in the USA (1997), the energy drink market has grown exponentially. Regulation of energy drinks, including content labelling and health warnings differs between countries, with the most lax regulatory requirements in the USA, which is also the largest market. An absence of regulatory oversight has resulted in aggressive marketing of energy drinks, targeted primarily at young males, for psychoactive, performance enhancing and stimulant effects [Reissig et al., 2009].

The measurement of pH is a practical method to assess the erosive potential (EP) of acidic drinks. Currently, dental erosion is considered a significant clinical problem in children and young adults. The present study shows that all commercially available energy drinks an EP due to their comparatively low pH, corroborating the findings of previous investigations [Seow and Thong, 2005; Ehlen et al., 2008]. The lowest pH value was recorded for Flash Power (1.52). Although a pH value equal or below 5.5 is considered as critical for enamel dissolution, mineral loss may begin even at higher pH [Birkhed, 1984].

Regarding titratable acidity, the values obtained for the tested industrialized energy drinks brands were lower than those reported in the literature [Ehlen et al., 2008]. The type of acid present in the beverages seems to influence the demineralising capacity of the product; citric acid, for example, has a greater erosive potential than maleic and phosphoric acids [Burato et al., 2002]. The chelating properties of citric acid can modify the erosion process in vivo by interacting with saliva as well as directly dissolving tooth mineral therefore beverages with low pH and containing citric acid are considered as being the most erosive [Lussi et al., 2007].

Of the energy drinks presented 7 had a total soluble solids content (TSSC) higher than 11%, which means 11 g of solids dissolved in 100 g of drink, with Flying Horse presenting the highest TSSC. A lack of similar studies evaluating TSSC of energy drinks precludes a comparison of our results to previous data.

This study evaluated the content of non-reducing sugars (e.g. sucrose); 7 samples presented sugar content over 18 g per 100 mL. Flying Horse had the highest non-reducing sugars value (54.3%). Some studies have analysed sugar content of commercial brands of energy drinks and found values ranging from 21.5 g [Alford et al., 2001] to 35 g per 100 g [Clauson et al., 2008].

Acidic beverages are thus likely to be a major factor in the aetiology of dental erosion that is common among children and adolescents today. Although saliva has a protective role, relatively high volumes are required to neutralize the EP of the acidic beverages [Seow and Thong, 2005]. Furthermore, the nature of consumption whereby sipping for extended periods or concurrent with mouth breathing during athletic training is used, could increase the opportunity for erosion to occur [Ehlen et al., 2008].

A group of peptides, known as CPP, have been shown to stabilize calcium and phosphate preserving them in an amorphous or soluble form known as amorphous calcium phosphate (ACP) [Llena et al., 2009]. Adding Casein Phosphopeptide ACP (CPP-ACP) to energy drinks reduces their EP with no change in flavour when added in a proportion of over 0.09% [Ramalingam et al., 2005].

The EP with consumption of acidic beverages is an important consideration for nutritionists, dentists and physicians when counselling patients. Patients with high consumption of acidic beverages, decreased salivary flow, prolonged beverage holding habits, or mouth breathing could be at an increased risk for dental erosion [Ehlen et al., 2008]. Therefore, the pH and sugar content values obtained in the present study may be considered high.


The energy drinks evaluated in this study have a high erosive potential, as they present low pH and a high non-reducing sugar content. Therefore, patients should be instructed on the potential deleterious effects of such beverages on the dental hard tissues when often consumed.


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A.L. Cavalcanti *, M. Costa Oliveira *, V.G. Florentino *, J.A. dos Santos **, F.F. Vieira **, C.L Cavalcanti ***,

Dept of * Paediatric Dentistry, School of Dentistry, ** Analytical Chemistry, School of Chemistry, State University of Paraiba, *** Nutrition, School of Nutrition, Federal University of Paraiba, Joao Pessoa; PB, Brazil.

Postal address: Prof. A.L. Cavalcanti. Avenida Manoel Moraes, 471/802--Manaira 58038-230 Joao Pessoa, PB, Brasil

Table 1. Energy drinks, composition and manufacturers
of energy drinks as used in Brazil.

Energy Drink          Composition            Manufacturer

Bad Boy Power Drink   taurine, caffeine,     Horizonte Dist. Import.
                      glucoronolactone and   Export. Ltda

Red Bull              taurine, caffeine,     Red Bull GmbH
                      glucoronolactone and

Red Bull Sugarfree    taurine, caffeine,     Red Bull GmbH
                      glucoronolactone and

Flying Horse          taurine, caffeine,     Globalbev Bebidas e
                      glucoronolactone and   Alimentos Ltda.

Flying Horse light    taurine, caffeine,     Globalbev Bebidas e
                      glucoronolactone and   Alimentos Ltda.

Burn                  taurine, caffeine,     Coca-Cola Femsa Brasil
                      glucoronolactone and

Night Power           taurine, caffeine,     Indaia Brasil Aguas
                      glucoronolactone and   Minerais Ltda.

Flash Power           taurine, caffeine,     Alflash Dist. Bebidas
                      glucoronolactone,      Ltda.
                      inositol and sucrose

220V Energy Drink     Guarana extract        Newage Ind. Com.
                                             Bebidas e Alimentos

Table 2. Distribution of the energy drinks according to the
mean values for endogenous pHTA, TSSC and sugar in samples
of Brazilian energy drinks

                          pH            acidity

Energy Drink         Mean     DP     Mean     DP

Bad Boy Power        2.70    0.02    1.04    0.01

Red Bull             3.20    0.01    0.82    0.01

Red Bull Sugarfree   3.14    0.03    0.97    0.06

Flying Horse         2.77    0.01    0.82    0.03

Flying Horse Light   2.89    0.00    0.81    0.03

Burn                 2.27    0.01    0.64    0.04

Night Power          2.83    0.03    0.72    0.06

Flash Power          1.52    0.00    0.81    0.03

220V                 2.47    0.03    0.56    0.03

                          TSSC            Sugar

Energy Drink         Mean     DP     Mean     DP

Bad Boy Power        12.00   0.00    39.64   0.00

Red Bull             11.75   0.00    38.96   4.49

Red Bull Sugarfree   2.00    0.00    0.00    0.00

Flying Horse         12.58   0.14    54.33   1.15

Flying Horse Light   1.66    0.14    0.00    0.00

Burn                 12.41   0.14    34.93   1.84

Night Power          12.25   0.00    52.15   0.00

Flash Power          11.76   0.05    19.43   0.80

220V                 11.73   0.20    18.00    0.0
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Article Details
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Author:Cavalcanti, A.L.; Oliveira, M. Costa; Florentino, V.G.; dos Santos, J.A.; Vieira, F.F.; Cavalcanti,
Publication:European Archives of Paediatric Dentistry
Article Type:Report
Geographic Code:3BRAZ
Date:Oct 1, 2010
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