Energy drinks have become popular among people from all age groups because of the instant supply of energy and mental alertness. The main component of these high energy drinks is caffeine. Several studies have reported the negative effects of caffeine consumption in any form. Animal studies have shown the negative effects of energy drinks containing caffeine on cardiovascular, renal, and neuro-cognitive functions. There are no studies to evaluate the effects of energy drinks on renal function in the human population. The most famous energy drink in Iraq is the caffeinated energy drink, Tiger. The consumption of this drink has dramatically increased in Iraq. So, with this premise, the present study aimed to evaluate the effects of high energy drink (Tiger) on renal function. Forty-nine participants who had no history of any systemic illness, non-alcohol consumers, and non- smokers, who consumed high energy drink (Tiger) for at least 90 days and 49 age and sexmatched healthy participants who did not consume any high energy drink were recruited for the study. The baseline and post 90 days serum creatinine and blood urea were measured by using the kit-based method. The paired sample t-test was used to compare the baseline and the post 90 days of serum creatinine and blood urea levels. A p value <0.05 was significant. The serum creatinine and blood urea levels were significantly increased in the group of participants who consumed high energy drink (Tiger) at 90 days of high energy drink consumption. There was a significant change in the levels of serum creatinine and blood urea in the control group. The elevated levels of serum creatinine and blood urea are indicative of renal damage caused by the consumption of high energy drink (Tiger). The results of the present study suggest that indiscriminate use of high energy drinks should be stopped.
High energy drinks, Tiger, Caffeine, Renal function, Creatinine, Blood urea
The energy drinks were introduced in the global market in 1987. Since its introduction, it has gained popularity among people. Energy drinks increase the mental alertness, physical strength/ stamina, promote brain response, reduces lethargy, and tunes the body in an active state [1,2]. The major active ingredients of energy drinks are caffeine, taurine, guarana, glucuronolactone, vitamins, and carbohydrates. Carbohydrate components serve as a source of energy and the caffeine acts as the stimulant of the central nervous system .
The energy drinks reduce the feeling of lethargy and activates the body by reducing the feeling of tiredness. This is the main reason of the popularity of the energy drinks. Energy drinks increases the performance of the consumers. It becomes an abuse in the people who over drink them beyond the allowed concentration of caffeine, especially the students and the athletes . The major problem with the energy drinks are the variable concentrations of caffeine and other psychoactive components . Unregulated or indiscriminate consumption of energy drinks may cause poisoning and may affect several organs . Reports suggest the overuse of energy drinks to be associated with caffeine poisoning seizures , strokes , and gonadotoxic effects .
The consumption of energy drinks has drastically increased in the recent past (Saad, 2014) and has reached $52 billion in 2016 . Energy drinks constitute a major part of the US sports and weight management market [9, 10]. According to a study, about 66% of children consume at least one carbonated drink and about 77% adolescents consume these drinks daily . The popularity of these drinks is more in the males as compared to the females .
Studies in animal models have shown adverse effects of energy drink consumption on the liver and kidney morphology and functions [13-15]. The rats treated with energy drinks showed increased levels of blood urea and creatinine [16,17].
These energy drinks are sold as dietary supplements and escape the Dietary Supplement Protection Act claims. There are several adverse reports related to the consumption of energy drinks. In 2011, the number of emergencies due to the consumption of energy drinks crossed 20,000. Majority of these cases were due to the misuse of these energy drinks . Energy drink consumption is rapidly increasing in the people in all the age groups. This increase popularity of energy drinks raises a serious public health concern due to overdose of caffeine . The major misuse or abuse results when people use these energy drinks with other prescribed drugs, alcohol and/or other illicit drugs . As per reports, about half of the energy drink consumers are constituted by the children, adolescents, and young people. Majority of the caffeine overdose due to the drinks are reported in people younger than 19 years . Since these energy drinks contains large doses of stimulants but are labelled as dietary supplements so these products escape the US Food and Drug Administration (FDA) caffeine limits [20-22]. The recommended limits for caffeine are 71 mg per 12 ounces in cola-type beverages and up to 200 mg per dose every 3 to 4 hours for over-the-counter drugs .
Caffeine toxicity is associated with several neurological and systemic disorders such as tremors, agitation, anxiety, irregular heart rate, high blood pressure, insomnia, psychosis, seizures, and cardiovascular instability [20, 21, 24, and 25]. The caffeine toxicity worsens when consumed together with other stimulants such as prescribed drugs and alcohol . A recent study conducted in albino rats to evaluate Pepsi cola and Tiger beverages on physiological parameters and histopathological changes highlighted that the treatment of these energy drinks resulted in increased body weight, sperm morphological defects, increased blood urea, glucose, and triglyceride concentration as compared to the control group . Tiger is a very popular energy drink in Iraq. With the premise of this background, the present study was conducted to evaluate the effects of energy drink (Tiger) consumption on the renal function in a healthy population in Iraq. We evaluated the levels of serum creatinine and urea as measures of renal function in healthy participants who consumed the high energy drink for at least for 90 days and in a group of age and sex matched of participants who never consumed the drink. We observed a significant increase in the serum levels of creatinine and urea in the group that consumed the energy drink (Tiger) for at least 90 days. There was no significant change in the levels of serum creatinine and urea in the control group.