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Energy drinks: a trigger for heart attacks and stroke?

When a 17-year-old girl, with a potentially life-threatening heart disorder, recently presented to me with an abnormally fast and irregular heart rhythm, I wondered how the natural history of her disease…

Energy drinks are largely marketed to youths and young adults. hectore/Flickr

When a 17-year-old girl, with a potentially life-threatening heart disorder, recently presented to me with an abnormally fast and irregular heart rhythm, I wondered how the natural history of her disease could so abruptly lead to a potentially fatal electrical rhythm disturbance.

Until I questioned her more about the moments leading to the rhythm problem.

Uncharacteristically, she had consumed a significant volume of a popular energy drink. Within an hour, she was in hospital receiving electrical shocks to her heart to bring it back to a normal rhythm. A mere coincidence, or did consuming an “energy drink” trigger her potentially fatal heart rhythm?

Energy drink consumption has grown exponentially over the past five to ten years. Sales are increasing at double the rate of total carbonated beverage sales.

The drinks are primarily targeted at the vulnerable youth and young adult market with aggressive advertising and marketing. And the potential medical complications of ingesting such drinks are becoming apparent, to both cardiologists and other health specialists.

So what is in energy drinks that could potentially trigger cardiac events? These drinks typically comprise of high levels of caffeine, guarana, taurine and sugar, with various other amino acids often also included. Indeed, at the time of this article being published, there’s no regulation on ingredients included in energy drinks in Australia or the United States.

The combined levels of caffeine in these energy drinks are much higher than a standard cup of coffee. And adverse events and complications from energy drinks largely arise from their caffeine content.

What’s more, energy drinks are intended to be drunk fast, and more recently, have been condensed to smaller volumes – so-called “energy shots”. These are freely available in petrol stations and other convenience stores.

Energy drinks can contain high levels of taurine, caffeine and sugar. The Master Shake Original/Flickr

So what are the medical effects of energy drinks? Based on currently available peer-reviewed scientific literature, there are many. From a cardiac perspective, there are three main effects: an increase in heart rate, an increase in blood pressure, and evidence of increasing blood viscosity that can lead to clots forming in the heart and beyond.

Most recently, three independent cases have been described in the medical literature where consumption of energy drinks led to catastrophic consequences, including cardiac rhythm disturbances and cardiac arrest.

Many other, non-cardiac effects of energy drinks have been reported, including anxiety, insomnia, vomiting, nervousness and irritability. As well as this, many young adults combine high-energy drinks with alcohol or physical activity, which can further exacerbate the potential risks of active ingredients.

The three recent cases highlight the potential detrimental cardiac effects of energy drink consumption, particularly in those who may be predisposed to arrhythmias because of underlying genetic heart disease.

Given the potential catastrophic consequences of energy drink consumption among susceptible young individuals, greater community education and awareness needs to be promoted.

This may include somewhat more drastic measures, including more graphic and clear warnings on energy drink cans to convey the potential dangers, much like the highly successful packaging of cigarettes, which include images of the consequences of smoking such as cancer. Another key initiative may be to restrict the sales of energy drinks to children and adolescents, often the target of energy drink advertising and under significant peer influence.

The collective goal of such measures is to prevent the incidence of potentially life-threatening cardiac rhythm problems, particularly in the young, by raising awareness in the community of the potential detrimental effects of energy drinks.

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35 Comments sorted by

  1. Nick Stafford

    writer

    Hi Chris

    thanks for this interesting article. Caffeine is understood in our society as a non-drug drug, by which I mean we, as a culture, are in denial about caffeine being a drug, and an addictive one at that.

    Clearly it causes less harm than the other two legal drugs, and I would argue all the illegal drugs too, but as your research demonstrates, it is not as harmless as many people would argue.

    I only have one issue with your essay; that is your representation of engergy drink consumers…

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    1. Sue Ieraci

      Public hospital clinician

      In reply to Nick Stafford

      I disagree, Nick. I see two main areas where caffeine consumption from drinks marketed to youth differ from coffee consumption.

      Firstly, the cultural use of caffeine in coffee is mostly in a relaxed atmosphere, as a hot drink, and not "sculled". While people DO recognise caffeine as a drug (of course we do - don't you know anyone who drinks coffee to stay awake?), the vast majority of people use if only in late teens or adulthood, drunk hot and relatively slowly. Most people recognoise the "rush…

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    2. Lisa Hodgson

      Director

      In reply to Sue Ieraci

      Chris, thanks for your awareness on this issue. These drinks have concerned me since their inception. Do we really have to wait for a large enough sample of case studies, or even a death to solve this problem?

      It looks like we agree on something Sue:) You've differentiated the two coffee habits nicely and the vulnerability of our youth in the way these drinks are presented and consumed.

      I see young people as vulnerable in another way in that they are continuously exposed to a bombarding of…

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    3. Chris Semsarian

      Professor of Medicine at University of Sydney

      In reply to Sue Ieraci

      Thanks Sue. As a simple cardiologist, I am reporting what I'm seeing! More and more - young people coming in with arrhythmias after consumption of energy drinks. Its now being reported more and more in major international medical journals. Its a reality

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    4. Luke Weston

      Physicist / electronic engineer

      In reply to Sue Ieraci

      Sue, I'm curious to know what the "several xanthine-like compounds" are specifically, other than caffeine itself, that are actually present in any pharmacologically-significant concentration in any of these manufactured beverages and what literature or evidence you can point me to on this subject.

      I agree that the caffeine content listed on the label - and measured for FSANZ compliance - should be the total caffeine content present - including caffeine added as well as caffeine present in, say…

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    5. Sue Ieraci

      Public hospital clinician

      In reply to Luke Weston

      Hi, Luke

      Here is a good review of the issue:
      http://onlinelibrary.wiley.com/doi/10.1111/j.1541-4337.2010.00111.x/full

      You are probably right about the absolute xanthine concentration per serving, but I think the effects are likely to be magnified due to their social use: volume, temperature, sweetness and marketing.

      As I said above, very few twelve-year-olds would rapidly slam down two or three hot milk coffees over an hour, but they could easily do so with a small volume, sweet cold drink.

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    6. Nick Stafford

      writer

      In reply to Sue Ieraci

      Hi Sue,

      thanks for your response.

      You say I am bringing up a different drug when I talk about the need to discuss the use of caffeine in forms other than energy drinks? Caffeine is caffeine Sue, end of story.

      I do not dispute for one second that some young adults are using caffeine in a way that can cause harm to them. But can you not see that you can described the two different groups very differently. Coffee users to you are adults who use caffeine to become "warm slow and soothing" and…

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    7. Sue Ieraci

      Public hospital clinician

      In reply to Nick Stafford

      Wow - I'm attempting to "disempower young people"?

      "If there is an over-representation of young people and energy drinks, then that is due to their youth and attitudes towards drugs in general, far more than the form they take caffeine in.

      Not so, Nick. If that were the case, why would Chris Semsarian be seeing the cases he is seeing now?

      "Finally, if research was done on the actual amount of caffeine used, I am confident we would find high levels across all the age goups. Not just among the young." You are mistaking chronic consumption with acute high dose effect. The young are also more vulnerable to the effects.

      I hope this addresses some of your misconceptions, Nick.

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  2. rory robertson
    rory robertson is a Friend of The Conversation.

    former fattie

    Professor Semsarian, thanks for your excellent "red alert" on energy drinks. I share your anxiety that they could spark catastrophic consequences in hapless young consumers, and that warning labels on cans would be a good idea. More generally, energy drinks are chocca with added sugar and - whether or not they are an immediate trigger for heart attacks and strokes - it is clear that sugary drinks of all descriptions have been a key driver of increased consumption of refined sugar in Australia over…

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    1. rory robertson
      rory robertson is a Friend of The Conversation.

      former fattie

      In reply to Sue Ieraci

      Actually Sue, my main concern is not about sugar. My main concern is about the integrity of the scientific record. My main concern is that high-profile false facts are being published in peer-reviewed science journals, and that some local "scientists" have a basic lack of respect for facts. Dr Stanton has confirmed my observation that the Australian Paradox paper features factually incorrect conclusions (see below). So too has Professor Boyd Swinburn of Deakin University. Moreover, Dr Stanton…

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    2. Sue Ieraci

      Public hospital clinician

      In reply to rory robertson

      Rory - you need to understand that there are thousands of papers being published all over the world that won't influence public policy or guidelines - they're out there in the marketplace to be discussed and critiqued.

      If you continue to be obsessed about this one paper, my comment above stands.

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    3. rory robertson
      rory robertson is a Friend of The Conversation.

      former fattie

      In reply to Sue Ieraci

      Sue, like Dr Stanton earlier, you seem to miss the point that it is not okay for academics and other scientists to publish as fact things that are false, leaving the public misinformed. It is about academic and scientific integrity, and public trust. The scientific record is supposed to be populated by factually correct information, via the oversight of a competent peer-review process. Critically, the public debate - including the current debate on the causes of obesity, diabetes and related maladies…

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    4. rory robertson
      rory robertson is a Friend of The Conversation.

      former fattie

      In reply to rory robertson

      Professor Semsarian, since my issue is with academic and scientific integrity and my main focus now involves Dr Stanton's revelations earlier about the extraordinarily cosy agreed policy within the nutritionists' club not to correct false facts or retract negligent papers with false conclusions, I plan to migrate my discussion of that issue back to Dr Stanton's conversation page at https://theconversation.edu.au/two-books-one-big-issue-why-calories-count-and-weighing-in-6372 . Apologies for the intrusion.

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    5. rory robertson
      rory robertson is a Friend of The Conversation.

      former fattie

      In reply to Sue Ieraci

      Professor Semsarian and Dr Sue,

      I enjoyed the strong piece on energy drinks on Catalyst last week. Well done, Professor Semsarian. On that other matter I raised here last year - scientific integrity - I wanted to ask if you and Dr Sue share growing community concerns about the dark cloud over competence and integrity in science at your University's new Charles Perkins Centre? http://www.australianparadox.com/pdf/AustParadoxfalsifieddata.pdf

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  3. Alan Marshall

    Retired

    If GET-UP were to take on the manufacturers and distributors of these so-called energy drinks, and let the shareholders know where their profits are coming from, that might get the message through.
    All the time someone is making huge, easy profits out of vulnerable people, they are not going to stop it voluntarily.

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    1. Rosemary Stanton

      Nutritionist & Visiting Fellow at University of New South Wales

      In reply to Brendon J. Brewer

      Brendon

      There is an official FSANZ limit on caffeine content for drinks made in Australia. However, NZ sets its own laws (or doesn't) and the products can then be imported (legally). The MJA had a useful article recently (see https://www.mja.com.au/journal/2012/196/1/energy-drinks-health-risks-and-toxicity) noting that some cans (375 mL) contained 300mg caffeine. Some of the small 80 mL 'shots' have 80mg caffeine.

      The total caffeine content is supposed to be on the label, but apparently some companies don't include the caffeine from guarana in this.

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    2. Geoff Parker

      Chief Executive Officer - Australian Beverages Council

      In reply to Rosemary Stanton

      There are a myriad of mistruths in the public arena concernign energy drinks, their caffeine content and alleged circumventing by manufacturers of the very stringent food laws (and ACCC) here in Australia. So a little perspective is needed.

      With reference to the views expressed above, the Beverages Council and its members (representing 98% of the energy drink market) recognise their role in cooperating with scientific, regulatory and health bodies to clarify any misconceptions and queries surrounding…

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    3. rory robertson
      rory robertson is a Friend of The Conversation.

      former fattie

      In reply to Geoff Parker

      Geoff, more importantly, one of the "myriad of mistruths in the public arena" is that an "...analysis of [i] apparent consumption, [ii] national dietary surveys and [iii] food [beverage] industry data indicates a consistent and substantial decline in total refined or added sugar consumption by Australians over the past 30 years”. That is, there has been ”an inverse relationship” between sugar consumption and obesity. This, of course, is the spectacularly false "Australian Paradox" paper. In fact…

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    4. Rosemary Stanton

      Nutritionist & Visiting Fellow at University of New South Wales

      In reply to rory robertson

      Rory

      As I have said before, I cannot say how much sugar is consumed in Australia because we don't have any data. Indeed, we're unlikely to get such data because sugar is so ubiquitous and it is unlikely that any dietary survey will pick up all the sugar that is used. There is also evidence that people specifically under-report things they think are 'bad' - such as sugar and fat. I suspect the sugar industry may have a reasonable idea of consumption, although I wouldn't hold my breath waiting for…

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    5. Rosemary Stanton

      Nutritionist & Visiting Fellow at University of New South Wales

      In reply to Geoff Parker

      Geoff

      Your organisation may not produce or promote products that fall outside the FSANZ guidelines, but I am sure you are aware that they exist. To suggest that only energy drinks that fit the FSANZ guidelines are available in Australia is obviously not the case.

      I presume you are not so insulated from the consumers of energy drinks that you are not aware they are widely used to delay the sleepiness that comes with alcohol consumption, the idea being to stay awake for longer so you can drink…

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    6. rory robertson
      rory robertson is a Friend of The Conversation.

      former fattie

      In reply to Rosemary Stanton

      Dr Stanton, I must confess that you shocked me with your response. You confirm in your first sentence that you "cannot say how much sugar is consumed in Australia because we don't have any data". Yet you have no objection to a "peer-reviewed" scientific paper that claims that the trend in sugar consumption has been one of substanital decline, observing as fact "an inverse relationship" between sugar consumption and obesity. Eat more sugar, get thinner? Are you really that relaxed about scientists…

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    7. Rosemary Stanton

      Nutritionist & Visiting Fellow at University of New South Wales

      In reply to rory robertson

      Rory

      I have many objections to that particular paper and to the idea that sugar is not a problem. I have many objections to many other things as well. I express these objections when I can and try to get the correct message to the public - also when I can.

      I have expressed my opinion about the paper to the authors and - when it was published - I commented on it in several fora. I will almost certainly cite it at some stage as an example of something I consider to be incorrect. I just don't think I need to bring it up in every discussion on every topic.

      There are many many issues on which I feel strongly. I express my opinion and I try to formulate an appropriate response. When I am able, i publish such things.

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    8. Lisa Hodgson

      Director

      In reply to Rosemary Stanton

      "In a stunning reversal, world renowned pediatric gastroenterologist Prof. John Walker-Smith won his appeal against the United Kingdom’s General Medical Council regulatory board that had ruled against both him and Andrew Wakefield for their roles in the 1998 Lancet MMR paper, which raised questions about a link to autism. The complete victory means that Walker-Smith has been returned to the status of a fully licensed physician in the UK, although he had already retired in 2001 — six years before…

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    9. Byron Smith
      Byron Smith is a Friend of The Conversation.

      PhD candidate in Christian Ethics at University of Edinburgh

      In reply to Geoff Parker

      I'm not really a huge fan of carbonated sugar water as a product and am more than a little uneasy about the frequently unethical and even illegal behaviour of beverage giants (a quick internet search for one of the major brands followed by "fined" returned 54 million hits). Yet I found this response from Geoff Parker quite helpful.

      It may be that there are increasing instances of misuse of these drinks (especially when mixed with alcohol), but if caffeine's role in that equation is that it enables…

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    10. Sue Ieraci

      Public hospital clinician

      In reply to Lisa Hodgson

      Walker-Smith was exonerated due to his relatively minor involvement in the study methodology.

      Wakefield has not been exonerated, and the study's faults remain - there were only twelve children, who were referred to the study by lawyers who were planning to sue the vaccine manufacturers. Wakefield received money from these people, and had a patent on individual M,M and R vaccines.

      The GMC's findings against Wakefield are here:
      http://www.gmc-uk.org/Wakefield_SPM_and_SANCTION.pdf_32595267.pdf

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    11. Geoff Parker

      Chief Executive Officer - Australian Beverages Council

      In reply to Rosemary Stanton

      Rosemary,

      As a peak body, we work closely with state and federal enforcement agencies to ensure that all products meet not only our domestic regulations but that they also comply with prevailing community standards. Recently an imported energy drink with a certain brand name was squeezed off the shelves because it was offensive and gave an inappropriate message to potential consumers. This was due in part to repeated requests from this office to that state’s food regs enforcement agency as well…

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    12. rory robertson
      rory robertson is a Friend of The Conversation.

      former fattie

      In reply to Geoff Parker

      Geoff,

      There's an argument that energy drinks and other sugary beverages are as damaging for the health of Australians as alcohol. I recently spent a week in Cape York and visited one of the Cape's many remote Aboriginal communities. Thumb-tacked on the notice-board outside the (one) community grocery store was a report from the Menzies School of Health Research documenting that sugary products - particularly softdrinks - are a huge part of the dollars spent at the store. Something like 95…

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  4. Julie-Ann Robson

    logged in via Facebook

    My worry is that teens are drinking these as mixers. Where once they would order spirits with Coke (or lemonade etc) Vodka and an 'energy drink' has become a standard beverage for teenagers, and can be ordered from the bars they frequent. The consequence is that they stay awake long enough to consume more alcohol, which, combined with the dangers outlined in the article, should be of major concern to researchers.

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    1. Chris Semsarian

      Professor of Medicine at University of Sydney

      In reply to Julie-Ann Robson

      Yes, you raise an extremely important and relevant issue which extends the issues with energy drinks beyond direct cardiac effects, to behavioral and social problems relating to alcohol consumption

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  5. Luke Weston

    Physicist / electronic engineer

    1 cup (7 US fluid ounces) of drip or brewed coffee contains 80-175 mg of caffeine depending on how the coffee is prepared. An espresso shot contains about 100 mg in 1.5 - 2 ounces of liquid.

    http://www.ncbi.nlm.nih.gov/pubmed/762339

    That's 39-85 mg / 100 ml for drip or brewed coffee, and 169-225 mg / 100 ml for espresso, all of which are significantly higher than the Australian rule for maximum caffeine concentration in these caffeinated soft drinks, which is 32 mg / 100 ml.

    (Essentially…

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    1. Sue Ieraci

      Public hospital clinician

      In reply to Luke Weston

      Luke - see my comments above. The difference between tea/coffee drinking and "slamming down" cold, sweet energy drinks makes for a major difference in age-group, speed and volume of consumption.

      Very few thirteen-yr-olds slam down two or three hot espressos (espressi) within minutes.

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    2. Luke Weston

      Physicist / electronic engineer

      In reply to Sue Ieraci

      As with most drugs, what we should probably be doing is educating teenagers appropriately from a harm minimisation perspective, so they understand dangerous and inappropriate overuse of all drugs - caffeine included.

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    3. Sue Ieraci

      Public hospital clinician

      In reply to Luke Weston

      That's true, Luke, but caffeine wasn;t much of a drug of abuse for youth until it started being marketed to them in small, sweet, cold servings.

      I see a hint of "alcopops" influence here.

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