Energy drinks are still very popular. But what about their harmful effects on our health?

Author: Šárka Randáčková

Bodybuilding / Fitness

12.12.2018

11 minut čtení

Studies have attributed many adverse effects to energy drinks, especially for the cardiovascular system. However, their overall risk is quite low and depends on many factors.

The market for energy drinks is huge. In 2016, its turnover was estimated at $43 trillion. By 2025, this figure is expected to almost double.

Figure 1: US energy drink market (sales in trillions of dollars)

Between 2007 and 2017, surveys showed that 58% of young Canadians,[1] 53% of US military,[2] 51% of US students [3] and 35% of New Zealand adolescents[4] consume energy drinks. In other words, that's a big chunk of the young population.

What makes energy drinks such a hit with young people? The desire to kick-start energy levels is crucial: they are, in short, the coffee of a new generation. It's also the result of successful marketing campaigns,[5][6]availability and good taste.[7] Negative health effects are prevalent among most people,[8] but not enough to deter them.

What is an energy drink?

You won't find two identical products on the market. But traditional ingredients include caffeine, taurine, B vitamins, herbs (ginseng, guarana) and of course sugar or artificial sweetener.

Table 1: Common energy drink ingredients

Supplement	Dose*	Marketing claims	Potential benefits	Potential problems
Sugar	50 g+	Energy for the brain	Appetite stimulant	Excess energy intake
Caffeine	140 mg+	Stimulant and support for brain activity	Stimulant, nootropic	Tolerance, withdrawal, heart problems, sleep problems
Taurine	2000 mg	Improving blood flow	Antioxidant, heart health, insulin sensitivity	**
Niacin	40 mg	Helps the body create energy	**	**
Inositol	50 mg	Improves concentration	**	**
Vitamin B6	4 mg	Helps the body create energy	**	**
Vitamin B12	12 mcg	Helps the body create energy	**	**
Ginseng	50-400 mg	Improves concentration	Nootropic	Digestive irritation
Guarana	50 mg	Increases concentration and energy	**	**
L-Carnitine	50 mg	Promotes fat burning	**	**

* Normal dose (473 ml)

** None (too low dose)

We could rate each of the ingredients separately, but we wouldn't see a forest for the trees: the ingredients usually interact. [ 9][10] One study, for example, showed that consuming energy drinks improves brain function, while consuming the individual ingredients (caffeine, glucose, ginseng, and ginkgo biloba) does not.[9][10]Another study, for example, showed that taurine negated some of the effects of caffeine, so that consuming them together provided less energy and more headaches than consuming caffeine alone.

Two ingredients deserve special attention, however.

Caffeine

Caffeine is the main stimulant in energy drinks. The most popular brands contain roughly 150 mg of caffeine per can, not counting the caffeine content of the individual ingredients. Their caffeine content is therefore about 470% higher than a can of cola and 160% higher than a cup of coffee. Caffeine intake below 400 mg per day is considered safe, but this limit is dependent on genetics, health status, and sleep rhythm[11].

Take CYP1A2, for example. This enzyme is responsible for breaking down caffeine and other drugs. Its activity, and thus caffeine metabolism, is influenced by genetics and lifestyle (smoking, dietary habits, contraception...)[12] Adenosine receptors, which are genetically determined, can further influence, for example, sleep quality[13] and provide the basis for caffeine-induced anxiety[14].

Sugar

Carbohydrates per se do not cause obesity and its associated problems. However, consumption of sweetened beverages often leads to increased energy intake, which already contributes to obesity and its pitfalls. We are talking about diabetes, metabolic syndrome and fatty liver, especially in societies with sedentary lifestyles[15][16].

Are energy drinks harmful?

They definitely can.

The National Poison Data Collection System recorded 2.3 million calls in 2011. 4,854 (0.2%) of these were related to energy drinks.[17] Nearly two-thirds were related to contamination with unknown added substances. The main problems were seizures and cardiovascular problems such as arrhythmias and rapid respiration. The events described were worst when energy drinks and alcohol were consumed together.

The cardiovascular effects of energy drinks deserve special attention. Caffeine mainly affects the blood vessels, whereas the other ingredients mainly affect the heart.18Energy drinks are generally attributed with short-term adverse effects on cardiac blood flow to the brain.19 These effects are mainly related to the cooperation of caffeine and sugar and, to some extent, taurine and sugar.

Figure 2: Potential effects of an energy drink (Red Bull) and its components on blood flow and blood pressure

Some case reports link energy drinks to arterial fibrillation;[20] however, they speak of high doses and have not been confirmed by studies.21 Other cardiovascular changes associated with energy drinks include ST elevation,[22]cardiomyopathy,[23] cardiac arrest,[24] coronary vasospasm,[25] acute coronary thrombosis,[26] and aortic aneurysm.

Who is at risk?

Ladies planning a pregnancy should avoid excess energy drinks: over 400 mg of caffeine per day increases the risk of spontaneous abortion by 11%,[28]compared to a dose below 50 mg per day.

And it doesn't stop there. Pregnancy also shortens the half-life of caffeine, exposing the fetus to a higher dose[29].

And it doesn't stop there. Children and adolescents may be another at-risk group: Due to their smaller body size, they have a lower tolerance to energy drink ingredients. The poisoning report mentioned above reported that half of the incidents associated with soft energy drinks occurred in children under 6 years old, and another 10.5% were in children between 6-12.17

Children should keep their daily caffeine intake below 2.5 mg per kilo of body weight[31] - for a normal 10-year-old child this means under 80 mg per day (237 ml) of a regular energy drink.

Are there any positives?

Several trials have confirmed an increase in mental capacity.[32][33][34] In the right circumstances, caffeine's ability to suppress fatigue should be seen as a positive.[35] Studies have also confirmed the ability of energy drinks to improve muscle strength and endurance in sporting activities.[36]

Are energy drinks bad for you?

Studies have attributed adverse health effects to them, especially in conjunction with the cardiovascular system. Caffeine or sugar is usually to blame. But other ingredients - or combinations of ingredients - can also play a role. Like everything else, energy drinks can be harmful. However, this depends on many factors, such as the amount consumed and the health of the person drinking them in the first place.