The truth about sports drinksBMJ 2012; 345 doi: https://doi.org/10.1136/bmj.e4737 (Published 18 July 2012) Cite this as: BMJ 2012;345:e4737
All rapid responses
I agree with Dr. Cohen, but I'd like to add a few more comments concerning the truth about sports drinks' studies.
I have been questioning the methodological problems which have been repeated in most studies about sports drinks over the past 4 decades. The first problem is the fact that researchers have been comparing performance under two conditions, the first condition being "fasting for 10 to 16 hours and drinking a calory rich sports drink during the trial" and the second, "fasting for 10 to 16 hours and drinking a calory free placebo beverage."
It is pretty obvious that fasting for a long period will impair performance capacity. It is also obvious that feeding a starving person will certainly help his performance capacity as compared to what he could accomplish when he was not fed. Undoubtedly, these studies have shown that if you don’t eat anything for 12 hours, your aerobic performance capacity goes down. The second, but not less serious, is the fact that those researchers have concluded that sugar was an ergogenic aid, since the fasting subjects performed better when they received sugar instead of sweetener, when they should have concluded that fasting for many hours impairs performance.
It is also surprising that some researchers are too eager to suggest that sports drinks have ergogenic properties. This is linked to the idea that sugar is energy and therefore you should drink lots of CHO drinks while exercising. They don’t say that sugar eating is not a very healthy habit.
Another problem is that the authors didn’t seem worried about the possibility that subjects may have identified the treatment (sugar or sweetener). They never tested the subjects’ ability to identify the treatment by the taste of the beverage, but they say it was a double-blind study. Was it?
Even recently published papers ignore the existence of studies showing that if the subjects are fed before they begin the exercise trial, performance will not be improved by CHO feeding. They also ignore the mouth rinse studies which have shown that performance was improved when subjects simply rinsed their mouth with a CHO containing solution.
Competing interests: No competing interests
Actually the key complaint against Robert Murray's directorship of the Gatorade Sports Science Institute was that under his watch a false "Science of Hydration", exposed by the BMJ, was developed.
Whether or not this was achieved as the result of a conspiracy that he may or may not have orchestrated, is irrelevant.
He is however accountable, to those who suffered, for any adverse consequences that may have resulted from his actions or inactions.
Competing interests: Fully listed in previous responses
Criticizing clinical studies is not difficult and can be done with all published studies. This article fails by not offering a recommendation based on all the published studies read.
What does BMJ recommend for a marathon runner? A triathlete or Ironman athlete or long distance cyclist? Certainly not just straight water as clearly you showed this can lead to hyponatremia.
What does an athlete take away from this article?
Competing interests: First Endurance is the maker of EFS. An electrolyte sports drink.
I am unabashedly proud to say that I was the director of the Gatorade Sports Science Institute from its inception in 1985 until I left the company in 2008, the years during which Dr. Noakes alleges that the sports drink industry, led by Gatorade, worked to pervert science and mislead consumers about the benefits of sports drinks. I’m pleased that Tim believes I am bright enough to have duped every member of my staff, all of the GSSI advisory board members, all of my bosses and colleagues on the Gatorade business, a variety of professional organizations such as ACSM and NATA, US Army scientists, highly regarded scientific journals, as well as thousands of sports scientists and nutritionists around the world. I’m also pleased that I can take this opportunity to assure everyone that I am neither that smart nor that stupid.
Tim has been beating the sports-drink-industry-is-evil drum for many years, with the recent BMJ kerfuffle being just the latest example. In so doing, he - and now BMJ - has purposefully and erroneously impugned the reputation and integrity of professional organizations such ACSM and many of its distinguished leaders and members, actions which I find to be indefensible, both scientifically and ethically.
As for Tim’s lament that some of his papers were rejected, every scientist can empathize with that feeling, although I suspect that few scientists ascribe such rejection to an industry-biased peer-review process. Tim mentioned that “The reviews of these rejected papers were generally antagonistic and dismissive, in line with the opinion expressed by the then head of the Gatorade Sports Science Institute.” I authored the paper to which Tim refers and did so in response to an article he published in the British Journal of Sports Medicine in 2006 that I thought unfairly and inaccurately depicted the relationship between the sports drink industry and the sports science and medicine communities. Those who wish to read the articles can judge for themselves if my response was “antagonistic and dismissive.”
Others are also free to judge the strengths and weaknesses of the body of science related to sports drink efficacy. I strongly disagree with BMJ’s assessment of the strength of that science, but continued discussion along those lines is best conducted at scientific meetings and in peer-reviewed publications, rather than in media exposés. That said, for the foreseeable future, I’ll happily and confidently continue to consume sports drinks whenever I want to stay hydrated and fueled during exercise.
Competing interests: I was the director of the Gatorade Sports Science Institute from 1985-2008 and now advise companies large and small on topics related to exercise science and sports nutrition, including hydration and sports drinks.
To the Editor:
In his rapid response Dr Michael Sawka implies that poor science not conflict of interest issues explains why papers are not accepted by leading journals like the Journal of Applied Physiology and Medicine and Science in Sports and Exercise, the Editorial Boards and review panels of which sometimes contain individuals who have close associations with the sports drink industry. If this is true, relevant papers rejected by these journals must subsequently fail to attract high citation rates when published in other journals.
In fact a number of our papers rejected by those journals were subsequently published elsewhere and have already been cited 50 times or more in the literature. Hence they could not legitimately have been rejected because they were of poor quality. Typical examples include the following four papers1-4 already cited respectively 52, 74, 66 and 55 times according to the Web of Science.
Interestingly all 4 papers are of more than passing interest to the sports drink industry since they show that overdrinking of fluid alone causes exercise-associated hyponatraemia; that evidence for the benefits of sports drinks will be inflated by studies conducted in laboratories in which there is inadequate convective cooling; and that high levels of dehydration are found in the fastest finishers in two Ironman triathlons. In fact there was an inverse relationship between finishing time and the extent of weight loss in those two Ironman races so that more weight loss was associated with faster finishing times. The reviews of these rejected papers were generally antagonistic and dismissive, in line with the opinion expressed by the then head of the Gatorade Sports Science Institute5-7.
Of particular interest was a study8 in which we re-analyzed data from an industry-funded study. After review by 3 referees we were informed that the letter reporting our finding could not be published in the Journal of Applied Physiology since it was of poor science causing us to “misinterpret” the data. Perhaps the fact that our re-analysis found, inconveniently for the industry since it conflicts with years of their targeted messaging, that water not sodium balance determines the blood sodium concentration response to prolonged exercise, explains why this letter could not be published?
That study confirmed what we have been arguing since 1985 and which if enacted then would have saved lives and prevented the global spread of exercise-associated hyponatraemia.
1. Speedy DB, Rogers IR, Noakes TD, Wright S, Thompson JM, Campbell R, et al. Exercise-induced hyponatremia in ultradistance triathletes is caused by inappropriate fluid retention. Clin J Sport Med 2000;10:272-78.
2. Sharwood K, Collins M, Goedecke J, Wilson G, Noakes TD. Weight changes, sodium levels, and performance in the South African Ironman Triathlon. Clin J Sport Med 2002;12:391-99.
3. Sharwood KA, Collins M, Goedecke JH, Wilson G, Noakes TD. Weight changes, medical complications, and performance during an Ironman triathlon. Br J Sports Med 2004;38:718-24.
4. Saunders AG, Dugas JP, Tucker R, Lambert MI, Noakes TD. The effects of different air velocities on heat storage and body temperature in humans cycling in a hot, humid environment. Acta Physiol.Scand. 2005;183:241-55.
5. Murray B. Manufactured arguments: turning consensus into controversy does not advance science. Br J Sports Med 2007;41:106-07.
6. Noakes TD, Speedy DB. Case proven: exercise associated hyponatraemia is due to overdrinking. So why did it take 20 years before the original evidence was accepted? Br J Sports Med 2006;40:567-72.
7. Noakes TD, Speedy DB. Lobbyists for the sports drink industry: an example of the rise of "contrarianism" in modern scientific debate. Br J Sports Med 2007;41:107-09.
8. Noakes TD. Changes in body mass alone explain almost all of the variance in the serum sodium concentrations during prolonged exercise. Has commercial influence impeded scientific endeavour? Br J Sports Med 2011;45:475-77.
Competing interests: Fully disclosed in a previous rapid response; to the BMJ in a related article published in this series and in Waterlogged on page x.
Both Sawka and Hargreaves accuse the BMJ of alleging conspiracy, but our article does not allege this.(1) (2) (3) The BMJ points out that the evidence base for many claims and recommendations made by drinks companies and august sports medicine authorities is poor.
The article also highlights that manufacturers have developed close links with sports scientists who have gone on to develop hydration guidelines for all manner of organisations. Both Hargreaves and Sawka reiterate their ties with Gatorade.
This relationship between industry and experts is something the medical profession has been grappling with for many years. The Institute of Medicine in the US recommends that “professional societies and other groups that develop practice guidelines not accept direct industry funding for guideline development and generally exclude individuals with conflicts of interest from the panels that draft the guidelines.”(4) These recommendations are followed routinely by influential national guideline groups such as the US Preventive Services Task Force and the National Institute for Health and Clinical Excellence in the UK.
Even though Hargreaves accepts that the facts were “generally accurate,” none of the respondents to the article has explained why the guidance given by experts and authorities does not acknowledge the limited evidence base—or at least provide major caveats.
Contrary to what Sawka says, the BMJ did not state that the American College of Sports Medicine (ACSM) said that sports drinks have “special” ingredients, and neither did we say that the 2007 position statement stated that these drinks prevent hyponatraemia.
The Institute of Medicine report that Sawka quotes from suggests: “Because of homeostatic responses some degree of over-hydration and under-hydration can be compensated for in the short term.” It also says “there is not a single level of water intake that would ensure adequate hydration . . . in all environmental conditions.” It concludes that there is a paucity of data about water and electrolyte needs.(5) This was not what the ACSM guidance concluded.
Lastly, the evidence he cites to support the association between heat exertion or stroke and dehydration is limited.(6) Although Sawka suggests that experimental and epidemiological studies have shown an association, these are limited by a lack of control groups and their design.
1 Cohen D. The truth about sports drinks, BMJ 2012;345:e4737. (19 July.)
2 Sawka MN. Feature article contains many inaccuracies. BMJ 2012;345:e5435.
3 Hargreaves M. No conspiracy exists. BMJ 2012;345:e5433.
4 Institute of Medicine. Conflict of interest in medical research, education, and practice. IOM, 2009.
5 Institute of Medicine, Food and Nutrition Board. Dietary reference intakes for water, potassium, sodium, chloride, and sulfate. National Academies Press, 2004. www.nap.edu/openbook.php?isbn=0309091691.
6 Sawka MN, Leon LR, Montain SJ, Sonna LA. Integrated physiological mechanisms of exercise performance, adaptation and maladaptation to heat stress. Comprehens Physiol 2011;1:1883-928.
Competing interests: No competing interests
This article is of great interest and highly relevant. It highlights what seems to be a growing issue with people regularly reaching for their bottle of sports drink or water. I see many of my medical student peers displaying this habit.
Malinauskas et al discuss in their paper, how students use sports drinks in a variety of situations . An interesting question to pose, enhanced by the current Olympic press coverage regarding doping, is whether sports drinks and sport drink use provides students taking an exam an unfair advantage?
1.Malinauskas, B, Aeby V, Overton R, Carpenter-Aeby T and Barber-Heida K. A survey of energy drink consumption patterns among college students Nutrition Journal 2007, 6:35
Competing interests: No competing interests
The American Physiological Society (APS) was disappointed that you did not seek clarification from us before you implied that APS was somehow beholden to Gatorade Sports Science Institute (GSSI) in your article, “The truth about sports drinks (page 6, box 3).” For the enlightenment of your readers, we wish to clarify the relationship between the American Physiological Society, the Journal of Applied Physiology (JAPPL), and the Gatorade Sports Science Institute (GSSI) to avoid misunderstanding.
APS’ relationship with GSSI is limited and thoroughly transparent. For the last ten years, the Society has received approximately $7,000 annually from GSSI. These funds have been used exclusively to establish two of the 13 awards the members of the Society’s Environmental & Exercise Physiology (EEP) Steering Committee award to students: The Gatorade Beginning Investigator Award and the Gatorade Predoctoral Investigator Award. As our website states, the candidates who receive the awards are those “whose investigation in either environmental, exercise or thermal physiology has been judged by the Steering Committee as an outstanding example of experimental research,” and other technical criteria, such as being a first author on an abstract. The research is broad, as evidenced by the abstract titles of the 2012 awardees: “Locally-mediated cutaneous vasoconstriction is augmented in essential hypertensive humans,” and “Mitochondrial glutathione depletion reveals a novel role for pyruvate dehydrogenase as a key H2O2 emitting source.” The research projects have no connection to sports drinks and no Gatorade employee had any role in the selection process.
Dr. Michael Sawka, who is named in the article, is the former chair of the EEP Steering Committee. His appointment as an editorial board member since 1991 and a Consulting Editor since 2011 for the Journal of Applied Physiology was due to his research qualifications. An online search demonstrates that although he has published extensively on the physiology of heat stress and hydration he has not published any papers regarding potential benefits of sports beverages.
Dr. Mark Hargreaves has served as a Consulting Editor to the Journal of Applied Physiology since 2005 after serving as an editorial board member from 2000-2005. At no time during this 12 year period was he involved in the final acceptance or rejection of any manuscript regardless of whether or not they involved sports drinks. During the last four years he has reviewed 16 manuscripts of which one dealt with the sports drinks, albeit in a broad way.
Please do not hesitate to contact APS Executive Director Martin Frank, Ph.D. or JAPPL Editor-in-Chief Peter Wagner, M.D. in the event you need additional information.
Martin Frank, Ph.D., Executive Director
American Physiological Society
Peter D. Wagner, M.D., Editor-in-Chief
Journal of Applied Physiology
Distinguished Professor of Medicine and Bioengineering, School of Medicine, University of California, San Diego
Competing interests: I am the Executive Director of the American Physiological Society, which represents more than 11,000 physiologists worldwide and is publisher of the Journal of Applied Physiology, one of the Society’s 13 peer-reviewed publications.
The recent BMJ feature “The truth about sports drinks” makes for interesting reading, but contains a number of inaccuracies and presents one particular view on the role of sports drinks. In relation to “truth” in medical research, I refer readers to a recent Lancet editorial (379: 2118, June 9, 2012). Of greater personal concern was the clear implication that I used my association with commercial interests to influence editorial duties for the American College of Sports Medicine and Journal of Applied Physiology. I reject such an assertion. Had your investigations editor contacted me, I would have provided the following information for her article:
• I am Professor of Physiology at The University of Melbourne (since 2005) and prior to that Professor of Exercise Physiology at Deakin University (1996-2004).
• I served on the Science Advisory Board (SAB) of the Gatorade Sports Science Institute (GSSI) from 1996-2008 for which I received a modest annual honorarium and expenses-paid trips to the annual (SAB) meeting, held in conjunction with a scientific conference (yes, some locations were exotic, others less so). These conferences often covered, but were not limited to, issues of fluid, carbohydrate and electrolyte replacement during exercise.
• Between 1995 and 2005, I received a total of AUD$80,500 of unrestricted grant support from GSSI to undertake 4 separate research projects on aspects of carbohydrate metabolism during exercise, with a focus on mechanisms rather than performance. All of these research projects were approved by the relevant institutional ethics committees.
• I was not responsible for the final content of the 2007 ACSM Position Stand on fluid replacement, but did review aspects of the draft manuscript, specifically the section related to carbohydrate supplementation during exercise. My financial links to GSSI were declared and ACSM has clear policies for managing such conflicts.
• I was a member of the editorial board of the Journal of Applied Physiology from 2000-2005 and am currently a Consulting Editor (2005-present). In that role, I have overseen three highlighted topics on fatigue during exercise, muscle plasticity and exercise & metabolic syndrome. I have never had responsibility for the final acceptance/rejection of any manuscript (that role is undertaken by the Associate Editors and ultimately the Editor) and to the best of my knowledge the dominant criterion for acceptance is scientific merit/quality. I do undertake reviews of specific manuscripts and in the period 2009-2012 (for which records are available) I have reviewed 16 manuscripts – only one was on a topic broadly relevant to sports drinks. I have neither the desire, nor the opportunity, to determine the acceptance or rejection of research papers on sports drinks that have been submitted to Journal of Applied Physiology.
It was unfortunate that a series of related facts (generally accurate) were connected to propose an elaborate conspiracy. The reality is not so sensational.
Competing interests: No competing interests
The BMJ feature The “Truth” About Sports Drinks contains in places portions of text that are essentially executive summaries of industry conspiracy theories and promotion of hyponatremia through irresponsible guidelines outlined in Prof. Noakes’ book Waterlogged.1 In addition, the trade ‘secrets’ of sport drink manufacturers are ‘exposed’. The ‘evidence’ presented for the conspiracy is thin at best and has been contested (see as one example one response from one ‘insider’ Dr. Michael Sawka - http://www.bmj.com/content/345/bmj.e4737/rr/595711).
More insidious, and of arguably greater consequence, is the suggestion that sport drinks promote obesity. Rather than a careful juxtaposition of philanthropic ‘concern’ from the Robert Wood Johnson Foundation with a statement from Coca-Cola authoritative reviews have been written on this topic.2-5 What emerges is that childhood obesity is decidedly complex and multifactorial and sport drinks are not a single reason, and neither is sugar, for obesity any more so than convenience foods, physical inactivity, public policy on physical education, and a multitude of other things including but not limited to genetics, socioeconomic status, and parental/family influence. A relevant question is whether sport drinks are part of the solution to obesity? The answer is likely no, but I would have thought that at least an acknowledgement that the problem of obesity is complex would be warranted and not a vaguely worded conclusion on the topic?
What would have been prudent to see in this piece was perhaps some kind of response or opposite viewpoint to Dr. Noakes’ opinions. Since the title of the piece bore than name ‘truth’ it would seem to be quite absolute in nature. Quite to the contrary, however, a number of people named in Ms. Cohen’s piece would, I am sure, have liked the opportunity to respond and present and entirely opposite viewpoint. As a recent piece in the Lancet concluded,6 rarely in science is truth is apparent and instead relative certainties are given. Quoting Bertrand Russel, “when a man tells you that he knows the exact truth about anything, you are safe in inferring that he is an inexact man.” 6
The use of evidence-based medicine (EBM) to study the effects of sport drinks is also an interesting take. EBM is a tool conceived by Dr. Gordon Guyatt7 and represents the careful use of clinical evidence in making decisions about individual patient care. Supporters of EBM posit that the integration of best research evidence makes it an ideal model for guiding clinical practice. EBM also reduces variation among clinical practices, discourages the use of unproven interventions, and brings consistency to clinical guidelines. However, much of what is subjected to EBM is based on practice in healthcare. The populations are large and the money almost endless, relatively speaking, to the money spent on studying a sport drink research. Stacked against the weight of a Nation’s healthcare budget or funding for large-scale pharmaceutical industry-funded clinical trials for example how can something as insignificant as a sport drink ever hope to achieve the same grade for study quality as a non-industry funded comparison of different forms of chemotherapy for treatment of a particular metastatic cancer? Critics of EBM, however, suggest that EBM prioritizes experimental evidence over pathophysiological presentation, case histories, and clinicians' observational expertise. They argue that EBM does not allow autonomy of the doctor-patient relationship and instead limits a patient's ability to choose which treatment is best for their unique circumstances. There also arguments that EBM clashes with the framework of many culturally-oriented, traditional approaches to healthcare. While sport drinks don’t lend themselves to patient-clinician interactions, the original scenario for which EBM was designed,7 one could insert for the words patient, athlete, and coach for clinician? Or an alternative substitution for patient might be consumer?
The lack of any opposite viewpoint to the views presented in this feature (and the BBC program that accompanied the feature) leads the casual reader/viewer to form an easy conclusion. But science is rarely that easy and while cleverly framed viewpoints are one way to present an idea under investigation, which is usually a formal or systematic examination, this feature has not done service to this credo.
(1) Noakes TD. Waterlogged. Human Kinetics; 2012.
(2) Verloigne M, Van LW, Maes L, Brug J, De B, I. Family- and school-based correlates of energy balance-related behaviours in 10-12-year-old children: a systematic review within the ENERGY (EuropeaN Energy balance Research to prevent excessive weight Gain among Youth) project. Public Health Nutr 2012; 15(8):1380-1395.
(3) Libuda L, Kersting M. Soft drinks and body weight development in childhood: is there a relationship? Curr Opin Clin Nutr Metab Care 2009; 12(6):596-600.
(4) Malik VS, Schulze MB, Hu FB. Intake of sugar-sweetened beverages and weight gain: a systematic review. Am J Clin Nutr 2006; 84(2):274-288.
(5) Flynn MA, McNeil DA, Maloff B, Mutasingwa D, Wu M, Ford C et al. Reducing obesity and related chronic disease risk in children and youth: a synthesis of evidence with 'best practice' recommendations. Obes Rev 2006; 7 Suppl 1:7-66.
(6) The truth about good medical research. http://www lancet com/journals/lancet/article/PIIS0140-6736(12)60924-6/fulltext [ 2012 379(9832)
(7) Oxman AD, Sackett DL, Guyatt GH. Users' guides to the medical literature. I. How to get started. The Evidence-Based Medicine Working Group. JAMA 1993; 270(17):2093-2095.
Competing interests: No competing interests