Energy drinks and adverse cardiovascular health effects: should we be worried?

February 15, 2016

We may turn to energy drinks for a quick-fix energy boost, but could these drinks be harmful to the health of our heart? New research suggests that drinking more than two energy drinks per day could lead to heart palpitations in otherwise healthy young adults. This could have serious implications for our overall cardiovascular health. Dr Katherine Livingstone, Alfred Deakin Postdoctoral Research Fellow at the School of Exercise and Nutrition Sciences, offers a brief introduction to the topic.

What are energy drinks?

The marketing of energy drinks is focused on providing a boost in energy levels and improving mental performance. These drinks have been gaining popularity among adolescents and young adults and are now a multi-million dollar industry. So much so that few people would admit to not being familiar with the popular slogan “Red Bull gives you wings”.  But does it give you wings? And why would it?

Caffeine is the main culprit

So these so called “wings”, or energy boosts, arise from the products being high in stimulants including caffeine, sugar and natural supplements, such as ginseng. Of these components, caffeine is the main ingredient.

Although recommendations vary, the European Food Safety Authority considers caffeine consumption to be safe up to 400 milligrams a day for a healthy adult. Worryingly, energy drinks can contain in excess of 200 milligrams of caffeine per can, and concentrated energy shots in excess of 400 milligrams per small bottle. This means that consuming just one or two of these drinks could be providing you with a substantial dose of caffeine.

What is the evidence?

So why would all this caffeine and ‘energy’ be bad for our cardiovascular health? Well, increasing evidence is emerging that energy drinks may be linked with increasing heart palpitations, high blood pressure and even, in rare cases, cardiac arrest.

A recent study published in the International Journal of Cardiology looked at whether drinking energy drinks was linked to cardiovascular health in 60 young adults between 13 and 40 years of age.

What did they find?

• 75% of individuals who drank more than two energy drinks in one day reported symptoms of heart palpitations within 24 hours of consumption
• This was compared to only 17% of low energy drink consumers
• The detrimental effect of energy drinks was greater in people who consumed energy drinks in conjunction with alcohol.

This study was based on a questionnaire, which makes it difficult to determine whether heart palpitations were attributable specifically to energy drink consumption in these individuals.

Nonetheless, these findings are similar to a previous study in 25 healthy adults, where adults participated in a randomised controlled trial to investigate the effects of energy drink consumption on cardiovascular health. Participants drank either an energy drink containing 240 milligrams of caffeine or a placebo (containing no caffeine). What were the results?

• Blood pressure increased by 6% following consumption of the energy drink, compared with 1% following the placebo
• Levels of norepinephrine, a stress hormone that increases heart rate, also increased after drinking the energy drink.

Although this was a randomised controlled trial and so a strong study design, the number of individuals in the study was small and only one energy drink was investigated.

It is also worth noting that caffeine may not be the only culprit in the case against energy drinks. Other components commonly found in energy drinks, such as ginseng, have been linked with cardiac arrhythmias too.

So what does those all this mean?

Moderation, moderation, moderation…

As a nutritionist, I am continuously advising people to consume in moderation, and the same rule of thumb applies to energy drinks.

Although high intakes of energy drinks may be linked with adverse cardiovascular health, when consumed only occasionally, they are unlikely to cause any harm to otherwise healthy individuals. However, in individuals with pre-existing medical conditions, such as heart disease, this risk may be higher.

What should you be aware of?

• High intakes of caffeine could lead to adverse cardiovascular health effects
• Be conscious of other sources of caffeine in your diet (e.g. coffee, tea, soft drinks, coffee-based snacks), which could add up
• Energy drink consumption should be closely monitored in adolescents, where they are more likely to drink more than one serving and combine it with other sources of caffeine and alcohol.
• In individuals with pre-existing medical conditions, such as heart disease, the risks attributable to energy drink consumption may be higher
• Energy drinks are just another sugar-sweetened beverage and have low nutritional value.

Dr Katherine Livingstone
Alfred Deakin Postdoctoral Research Fellow
School of Exercise and Nutrition Sciences
Deakin University