Energy drinks and population health: consumption pattern and adverse effects among Saudi population

Energy drinks (EDs) are beverages that are used to boost energy, increase physical performance, increase alertness and wakefulness, and elevate mood [1]. EDs consumption is increasing, particularly among young adults and athletes [2‐4]. EDs contain large doses of caffeine and other legal stimulants [1]. EDs first appeared in Asia and Europe in the 1960s; however, after the introduction of Red Bull® in Austria in 1987 and in the U.S. in 1997, the trend towards aggressive marketing of these EDs has grown tremendously. Since that time, the ED market has grown exponentially with nearly 500 new brands launched worldwide in 2006 and 200 new brands launched in the US in the 12-month period ending July 2007 [5]. The total U.S. retail market value of EDs from all sources was estimated to be $5.4 billion in 2006, and this value has shown a similar annual growth rate over this same period (47%) [5].

Caffeine containing EDs are consumed heavily among Saudis, particularly among adolescents, including females, and college students due to aggressive marketing of their overestimated ability to provide vast physical energy, which promoted their widespread use [2, 3, 6]. They are consumed to attain several effects, such as increased endurance, staying awake, fatigue relief, invigoration, memory/concentration boost and enjoyment of their taste [7]. Several EDs are available on the Saudi market, such as Red Bull®, Boozy®, Bison®, and Power Horse®. These EDs are available and easily accessible on the market, whether they are sold in small retail grocery stores or in large supermarkets. Due to this easy access to EDs and heavy marketing of these compounds in various multimedia sources, people are consuming more and more EDs [8]. Thus, the ED sector has exhibited strong worldwide growth with increased monetary rewards for companies that sell these products.

Caffeine is the key ingredient in EDs; it is also found in wide variety of beverages and some pharmaceutical products, which are commonly called psychoactive substances worldwide [9]. Caffeine has stimulating effects [10, 11] that can enhance mental and physical performance [10] and has been associated with improved alertness [12], concentration [10, 12], endurance, reaction time and mood [13, 14]. EDs typically contain high levels of caffeine, guarana, taurine, L-carnitine, vitamins, carbohydrates and sugar along with various other amino acids. According to Gunj et al., the typical dose of added caffeine is 7–32 mg/100 ml, giving a total dose of 35–150 mg in a 500-ml can [15]. Higher caffeine consumption is associated with increased adverse effects, including nausea, irritability and palpitations [16]. In addition, Caffeine has been demonstrated to increase the number of awakenings during sleep, sleep latency, and sleep interruptions [17]. The quantities of caffeine contained in single servings of EDs are not generally high enough to produce severe symptoms; however, at least one death has already been attributed to ED use as a 25-years old female who had pre-existing heart condition namely mitral-valve prolapse, which is present in 2.4% population, passed away after ingesting an energy drink that contained high concentrations of caffeine and guarana [18].

Two-hundred and 50 caffeine intoxication cases with an average patient age of (21) years old have been reported by the Chicago Poison Control Center, and 12 % of these cases suffered from medical complications that were attributed to EDs abuse [19]. A case study published in BMJ recently stated that in the US, approximately 23,000 emergency cases each year were due to dietary supplements [20]. Patients with pre-existing cardiac pathology or a history of seizures may be at greater risk [21‐24]. Several tachyarrhythmias, including atrial and ventricular ectopic beats, atrial fibrillation, ventricular tachycardia, and ventricular fibrillation, have been described in caffeine-poisoned patients [18, 25]. Caffeine-induced seizures may occur at low doses in susceptible individuals or as a result of overdose. One case series of 4 adults with new-onset seizures questioned an association with heavy EDs use [16].

It has been documented in the literature that excessive consumption of caffeinated EDs is associated with several potentially lethal adverse effects and toxicities [21, 23, 26‐29]. Caffeine containing EDs cause a rise in blood pressure (BP) due to increased systemic vascular resistance, which may worsen in severe cardiac disease, hypertension, hyperthyroidism or acute myocardial disease if precautions are not taken [30]. Additionally, methylxanthine-containing products stimulate gastric acid secretion, which should be cautiously considered in patients with peptic ulcer disease [31]. Over-the-counter (OTC) medications, such as NoDoz® and Midol®, contain between 100 and 200 mg of caffeine per tablet [32]. Some OTC drugs that are easily available for the public in the Kingdom of Saudi Arabia (KSA) contain 30–65 mg of caffeine, such as Panadol Extra® (65 mg), Adol Extra® (65 mg), Solpadine® (30 mg), and Fevadol plus® (35 mg). McCusker et al. reported that the U.S. Food and Drug Administration (FDA) has limited the caffeine content of sodas to 65 mg per 12 oz. (18 mg/100 ml); however, EDs are not currently subjected to the same FDA regulations [33]. According to Nawrot, the caffeine concentrations of various beverages are as follows: brewed coffee (56–100 mg/100 ml), instant coffee and tea (20–73 mg/100 ml), and colas (9–19 mg/100 ml) [34]. Smaller amounts can be found in chocolate (5–20 mg/100 g) and cocoa (7 mg/5 oz. cup) [32].

Several countries have demanded regulations on the labeling, distribution, and sale of EDs that contain significant amounts of caffeine. According to the European Union, Red Bull® EDs are required to have a “high caffeine content” label, and Canada requires labels indicating that Red Bull® should not be mixed with alcohol and that maximum daily consumption should not exceed two 8.3-oz cans [5]. Some countries have acted against the sale of EDs, including Red Bull®, in pharmacies, whereas France and Denmark have prohibited the sale of Red Bull® [35]. It has been suggested that warning labels on ED cans should inform the public of their high caffeine content and their potential adverse effect of raising BP [29].

In light of this, the objectives of the current study were to evaluate consumption pattern, to identify factors that influence consumption pattern, and to document the frequency of possible adverse effects of EDs among KSA population. Specifically, we aimed to obtain answers for the following research questions: How sociodemographic, levels of knowledge and perceived beneficial effects of EDs would affect their consumption pattern and intake frequencies, as well as what were the frequencies of possible adverse effects experienced by different consumer groups in the Kingdom. With that being done, we sought information about reasons for the popularity of EDs among participants, suitable replacements for EDs suggested by consumers and whether they attempted to quit consuming them. We also aimed to determine the consumption pattern of EDs with cigarette smoking as a negative health behavior in this study.

It has been documented in the literature that excessive consumption of caffeinated EDs is associated with several potentially lethal adverse effects and toxicities [21, 23, 26‐29]. While several studies were conducted to evaluate the prevalence of EDs consumption in the KSA [2, 3, 36, 37], to the best of our knowledge, this study is the first to elaborate factors that influence consumption patterns and rates among EDs drinkers and assess the adverse effects experienced by consumers.

Here, we report that gender did not affect average consumption patterns; even though the percentage of males consuming EDs daily or more than once daily was slightly higher than that of females, this difference was not statistically significant. A published study reported that the frequency of intake among both genders was affected by age [38]; however, that research group examined only participants between 14 and 19 years old, whereas we studied consumption patterns in a much wider age range (15–63 years old). It is important to mention that previous studies in the KSA have reported that young adolescent males drink more EDs than females [3, 36, 38]. After careful examination of the collected data, we found that the vast majority of consumers were 40 years old or younger (97%); they were rarely older than 40 years old. Consumption patterns were found to be altered by age as we found that younger study participants significantly consumed EDs more frequently than older drinkers; this pattern was consistent among all age groups, and this finding was similar to those of several previous studies [38, 39].

Educational level was found to determine the intake habits of EDs. We found that consumers who did not hold a high school diploma or were uneducated drank EDs more frequently than consumers with a high school diploma or above. However, almost 90% of study participants were equally distributed between high school graduates, undergraduate students or B.Sc. holders and above, and more than half of these EDs consumers drank EDs one to 3 three times per month. However, it is crucial to mention that the prevalence of EDs consumption in schools and colleges in the KSA and in many countries worldwide is very high, reaching nearly 50% and higher [2, 3, 36, 37, 40]. According to Sandra D. Reid et al., the usage of EDs by university students is a primary concern, as these students are the ideal target of companies promoting EDs [41]. Previous reports have shown that EDs usage is prevalent among undergraduate university students in the US and that 39–80% of these students used EDs at least once in the past [42]. According to Kopacz et al., 49% of university students in Poland used EDs during the academic year, whereas ED consumption significantly increased during examination times [43]. Hence, based on this information, it is crucial to create awareness campaigns about EDs for high school and university students.

Study participants attributed the popularity of EDs to intense advertisements in different media and their perceived invigorating effects. Other studies conducted in the KSA have reported similar results [3, 37]. EDs are promoted for their effects, including boosting energy, wakefulness, and alertness and improving physical and mental performance [41]. We did not find a significant difference in the purported beneficial effects of EDs among different consumption groups. Consumers in the KSA drank EDs to attain vitality and energy, alertness, mood elevation, focus and memory and to help them on long-distance driving trips around the vast Kingdom. It has been documented that moderate intake of EDs enhances physical and cognitive functions. In fact, several studies have proven that the active ingredients in Red Bull®, caffeine and taurine, improve physical endurance and psychomotor performance [10, 44]. Study participants expressed different thoughts about suitable replacements for EDs, and they mostly stated that coffee, tea and natural herbs were their choice of beverage instead of EDs.

Importantly, we deduced from our data that lack of knowledge is associated with heavier EDs intake. Total scores of knowledge about possible adverse effects of EDs was significantly less in daily EDs consumers than in the least frequent consumer group. Specifically, significant differences between daily drinkers and 1–3 times monthly drinkers in knowledge about harmful effects on the cardiovascular system were found. Fewer daily consumers knew about the possible rise in BP and HR by EDs than those in the least frequent EDs consumer group. Furthermore, more daily drinkers recommended EDs to others. In fact, it was astonishing to discover that other studies in the KSA have indicated a lack of knowledge of even the active ingredients in EDs. Musaiger et al. found that 47% of males and 52.3% of females who consumed EDs in the KSA were not aware of ED ingredients [3]. Aluqmany et al. reported that 69.3% of high school female students in Almadinah Almunawwarah, KSA, did not know about the ingredients in EDs [37]. Another study conducted in the United Arab Emirates (UAE) reported that 95% of university students were not aware of the high caffeine levels in EDs [45]. As the EDs market is expanding rapidly both regionally and globally, consumers should also take precautions and be familiar with the ingredients contained in EDs, such as vitamins; other EDs ingredients, such as niacin, exceed the recommended daily doses, which may lead to potential adverse effects and toxicity due to accumulation [46]. Together with our findings, these observations are disturbing, and promoting knowledge about EDs content and their possible adverse effects would probably decrease their intake frequency and hence reduce the health hazards associated with excessive intake.

A significant achievement of the current study was providing further evidence of possible health risks and adverse events related to EDs intake at different consumption levels. We report several adverse effects experienced by the study participants, and their percentages. More importantly, total score analysis of experienced adverse effects, indicates a significant difference between the daily EDs consumer group versus the 1–3 times monthly consumer group as the daily users reported experiencing more adverse effects that they attributed to their intake of EDs. Ten of these adverse events, namely, chest pain, insomnia, headache, constipation, diuresis, chronic fatigue, muscle fatigue, lack of rest, tremors, confusion and nervousness were significantly experienced more frequently in daily consumers than in the lowest EDs consuming group. While some studies estimated the frequencies of experienced adverse events among EDs drinkers in the KSA [2, 47], our study is likely the first in the KSA to provide evidence of the increased occurrence of adverse effects concomitant with increased EDs intake.

We also aimed to determine the consumption pattern of EDs with cigarette smoking as a negative health behavior in this study. The cigarette smoking rate in the KSA is high, reaching up to 37.6% in males and 6% in females [48]. Approximately 76.6% of the participants in our study reported being healthy despite the fact that significantly most EDs consumers in this study were cigarette smokers (58.6%), Moreover, we found that tobacco smoking determined consumption patterns as the majority of daily EDs consumers were smokers (77%) compared to 54% tobacco smoking among the 1–3 times monthly EDs consumers. Heavier EDs intake by tobacco smokers than non-smokers might be explained by the fact that tobacco smoking induces CYT P450 1A2, which enhances the metabolism of caffeine [49], hence requiring higher caffeinated ED intake. These findings are consistent with the findings of other studies that aimed to determine EDs and associated factors worldwide [40, 50]. Another negative behavior that can be associated with EDs consumption is alcohol intake. However, alcohol drinking is prohibited by Islam and banned in the KSA; thus, it was not feasible to study this association even though some people might drink alcohol illegally. It is worth mentioning that compelling evidence has been established regarding the consequences of mixing alcohol and EDs in a single alcoholic beverage (alcohol mixed EDs – AmEDs), which can lead to increased risks of adverse effects [51, 52]. It is important to mention that recent studies have shown that caffeinated EDs cause addiction and dependence [5]. When caffeine containing EDs are taken in high amounts, they induce arousal by caffeine’s effect on the pleasure area of brain, which is similar to the effects of tobacco, alcohol, and other drugs that should be treated with caution to avoid abuse [53].

We believe our study has several points of strength, and potential limitations. To our knowledge, it is the first study that assessed the patterns of consumption as well as the adverse effects of energy drinks on different age groups of Saudi population. The study was a national one as the participants were from all over the KSA. The study questionnaire consisted of 43 items to address most of the research questions being investigated, with a very good response rate (96%). However, as the nature of the study was an observational one, it was not possible to assess causality relationship especially when assessing the adverse reaction. The majority of participants were males and only 19% were females. When reporting adverse events, the difference between groups may be, at least in part, associated with other health conditions rather than solely being related to EDs consumption.

In conclusion, EDs intake is associated with many deleterious health effects that are proportional to intake level. Lack of knowledge is associated with heavier EDs intake. Young adolescents and high school and university students were found to consume EDs more frequently and at an increased risk of health effects. It is imperative, based on our findings, that regulatory authorities, including the SFDA, enact stricter regulations to control EDs marketing in the KSA. The level of awareness of possible negative health effects due to excessive EDs consumption must rise by assistance of different governmental entities, specifically, ministry of health and ministry of education.