O O Ø O O O O
Wake Up Call
Hello Dr. L. Lee Coyne
I see from your bio that you are an exercise physiologist and nutrition consultant. I also see you are a former professor of exercise physiology and nutrition at the Universities of Calgary, Manitoba, Toledo and Michigan.
Those are some pretty good credentials. I like a writer with credentials. At least, with real ones. There are a lot of bogus credentials floating around out there, so when I see a genuine Ivory Tower certification, it tends to get my attention.
I was reading your latest contribution to Impact magazine here in Calgary. I usually enjoy the magazine. Despite some minor differences with some of its affiliates in the past, I find their articles tend to be fairly well researched and written. And then I got the latest issue, and happened across your latest article: The High Cost of Energy.
Dr. Coyne, when exactly did you stop checking your sources?
The article is about energy drinks, a subject on which I have ranted in the past. In this article, you make a number of claims which are at best unsubstantiated, and at worst, patently false. Now, I’m not a nutritionist by trade (though technically, I could call myself one in 6 of 10 provinces). In fact, I’m a mathematician, and occasionally an engineer. I do read quite a bit about exercise physiology and sports nutrition, however, having gotten fed up long ago with the sheer volume of misinformation that seems to be out there. And it’s the subject of misinformation that has me off on a rant today. (So you know, this and perhaps a hundred of my other rants can be found at pintday.org).
As mentioned, I have a few beefs with your latest article, but the sentence that set me off was this one, on the subject of caffeine:
Energy drinks contain 50 to 160 milligrams of caffeine, two to three times the level in sodas, and up to four times the level in an average cup of coffee.
Now, where on earth do you get those stats? In fact, the first part of your statement is true. Red Bull, for instance, contains 80mg of caffeine in 250ml of liquid, for a ratio of 320mg/l. (I have no idea if mg/l is a common way to refer to caffeine content, but it will do for this illusration). Coca-cola, according to their web site, contains 23 mg of caffeine per 240ml, or 95 mg/l. Diet coke has around 31mg/240ml, or 129mg/l. So Red Bull wins by a factor of 2.5, or 3.4, depending on whether you go for the regular, or unleaded varieties respectively. But “up to four times the level in an average cup of coffee”?
Dr. Coyne, that’s just patently false. If I were to check with, say, the International Food Information Council (a lobby group that the Coca-Cola Company’s web site cites as an authority on caffeine content—no idea if they are authoritative, but it will serve as an initial comparison), Brewed coffee averages 85mg/240ml, or 354mg/l—actually a little more than Red Bull. If I take it a step futher, and hit the journals, I might discover that these numbers are a little low in the brave new Seattle-influenced world. Here’s what a 2003 University of Florida study found in a random sampling of Starbucks brews:
- Strongest: 564/473 = 1192 mg/l (3.7 times that of Red Bull)
- Espresso: 185mg/170ml = 1088 mg/l (3.4 times that of Red Bull)
- Average: 371mg / 473 ml = 784 mg/l (2.5 times that of Red Bull)
- Weakest: 259mg / 473 ml = 548 mg/l (1.7 times that of Red Bull)
Clearly, the average (Starbucks) coffee beats the pants off even the strongest of the energy drinks—a far cry from the statistics you quoted.
But it wasn’t just this comment that set me off. Later, you mention that:
Caffeine is also a diuretic that increases urine output that can lead to dehydration
Which is a result that is simply not backed up by science. Yes, caffeine is a mild diuretic, but recent studies show this effect to be minimal (akin to that of drinking water). On a whim, I dug a completely random survey article from a random journal (Caffeine, coffee and health, by Juliet Gray. Nutrition & Food Science Volume 98 Number 6 1998 pp. 314-319). Here’s what it had to say on the subject:
Caffeine is also a mild diuretic, acting on the kidney to increase blood flow and to decrease the reabsorption of sodium and water. It has been shown to increase the frequency of urination (Creighton and Stanton, 1990), but claims that caffeine has a dehydrating effect appear to be unsubstantiated. Patients with kidney stones are routinely advised to increase fluid intake and recent research involving 81,000 women (Curhan et al., 1998) has shown that drinking coffee reduces the risk of kidney stones by 10 per cent for each 200ml cup consumed daily, confirming the result of an earlier study in 45,000 men (Curhan et al., 1996).
So dehydration is not an issue. In fact, in many of the studies that you mention (regarding athlete performance and caffeine), the average amount considered is over 300mg of consumption—an amount that is considered “average” North American consumption, and equivalent to around 4 cans of Red Bull.
There have been reports of high-school football players admitted to hospital suffering from uncontrollable heart palpitations following the consumption of three to four “energy drinks” before and during a game.
First, this is the worst kind of anecdotal “fact.” Reports? Do you mean, ‘a report,’ or are there really multiple, independent reports of such a phenomenon? If so, where? I can find no such examples. Second, the amount you state is precicely the amount that is typically administered during the very scientific trials that show caffeine to have a beneficial effect on exercise. To quote:
One trial was performed an hour after ingesting decaffeinated coffee (Trial D), while a second trial (C) required that each subject consume coffee containing 330 mg of caffeine 60 min before the exercise. Following the ingestion of caffeine (Trial C), the subjects were able to perform an average of 90.2 (SE +/- 7.2) min of cycling as compared to an average of 75.5 (SE +/- 5.1) min in the D Trial.
In short, Dr. Coyne, am very disappointed by the apparent disregard to current research that is demonstrated in your latest article. Most of your claims, especially those related to the caffeine content of sports drinks do not appear to be supported by any kind of research I can find. This is not the calibre of article I would expect to find in the pages of Impact magazine, and certainly not that which should be expected of an author holding a Ph.D. in exercise physiology.
In short, I’m asking that you “wake up and smell the coffee.”
Sincerely,
Kjell Wooding
November 1, 2005
OOØOOOODCCXXVIII
November 2nd, 2005 at 4:01 pm
I’m a Certified Health Advisor and agree that sports drinks do not have to have caffeine to be an effective energy booster. Medifast from Take Shape for Life has recently introduced a high-protein sports performance shake for men and women and a low fat, balanced nutrition and energy shake and bar for weight management. Medifast is been around for 24 yrs. and knows what it’s doing in the area of health and fitness. I’ve attached a link to the blog artical I’ve written on it.
November 3rd, 2005 at 9:01 pm
KJ - the effects of caffeinne on the kidney are very entirely different from that of water. Dehydration is not a matter of urine out put but a matter of balancing the osmolarity of the blood plasma. Increasing water intake will increase urine volume but the because the body is shedding excess water. When caffeinne is consumed it blocks the effects of ADH (anti-diuretic hormone) on the distal collecting tubule of the nephron. This cause the distal tubule to reabsorb water which is not what it usually does. This area of the tubule is where water is usually brought back into kidney. So effectively caffeine is causing the body to excrete more water than it would under normal conditions. This will in turn raise the osmolarity of the blood. (osmolarity meaning the amount of solvent to solute i.e. water to electrolytes such as Na, K, Ca, etc…) Alchohol has similar effects as caffeine but it actually blocks the secretion of ADH from the pituitary. This effective blocking of ADH causes less water to be absorded by the kidney and therefore more lost to the distal collecting tubule through urination.
Now to the matter of your rant. I agree that a lot of the claims that this Ph D. is making are rather ludicrous. Caffeine only gives bursts of energy lasting only a few hours after that the system crashes. Not that is dangerous. ( in normal doses) The body just runs out of energy.
To quote the site about caffeine having similar effects as water.
“Moderate caffeine consumption causes a mild diuresis very similar to that of water (water, when consumed in large volume, increases urine output).”
That is a blatant twisting of the facts. urine volume is not an accurate measure of dehydration. Example you drink 3 liters of water during excercise and urinate one liter and lose another to respiration and sweat. That is not becoming dehydrated. You drink a 16 oz coke and urinate 32oz of fluid in the hour. That is a start on dehydration.
In short caffeine in normal doses meaning a few red bulls hear and there or coffee or what ever is not going to hurt you. As far as doing it with excercise. You may see benefits you may not. As long as you drink water before after or during excecise then the dehydration effects of caffeine will be negligable. Drinking only caffeinated beverages while excercising probably not the best idea. I think that at the most it will only make you really thirsty.
Hopefully the fact that I have a B.A. in Biology and am in the process of finishing a Masters in Neurobiology will lend some credence to my statements.
RB.
November 7th, 2005 at 9:14 am
for some reason redbull gets a lot of bad press.. but everyone worships coffee.. go figure.
wait till they learn about the import redbulls.. the non carbonated, cough syrup bottle ones. those are the best.
November 7th, 2005 at 3:36 pm
Glenn, you frighten me.
Meh? Did you read the article? Caffeine does have a positive effect on endurance athletes. Sports drinks, on the other hand, are a completely separate issue, aimed at rehydration and electrolyte balance, not energy per se. (Unless you’re talking carbohydrates and glycogen reserve, but I have a funny feeling you’re not).
File that under irrelevant. Care to explain why high-protein would be beneficial to sports performance? As a component of a recovery drink, perhaps, but for any kind of aerobic exercise, protein is largely irrelevant, unless you can show me any evidence to the contrary.
November 7th, 2005 at 3:46 pm
RB: Point taken. What then is a reasonable measure of dehydration? (or, for that matter, overhydration, since that is typically a more serious concern to a distance athlete.) Should we be focusing instead on electrolyte balance?
Seriously, does the average recreational athlete (presumably, the target of the original article) even care about the dehydration issue, since hyponatremia is a far worse outcome, and can occur simply by drinking plain-ol’ water? (a case where drinking a 16oz coke might actually help them, though off the top of my head, I don’t know what kind of electrolytes one might find in a coke).
October 19th, 2006 at 9:21 am
“Care to explain why high-protein would be beneficial to sports performance?”
Yes; in part because amino acids can be deaminated, e.g., alanine is deaminated to make pyruvate.
March 12th, 2008 at 9:09 am
Quite playing around you ametuers. I am a nutritionist for the Ottawa Senators, and our team promotes energy drinks for the benefit that it contains 4 times the caffeine that any coffee does! Its a natural laxative which allows for more consumption of food because it is digested much quicker than food. Contact me in my office at:714-850-2328
or email at foodsmartsenators@aol.com
March 12th, 2008 at 9:50 am
“Dr. Foodsmart”, I would love to know where you are getting your facts.
Red Bull contains 80mg caffeine per 250ml (320 mg/l). It’s printed on the can.
Can you indicate any reputable source that indicates coffee contains 1/4 this amount? (That would be 80mg/l). Even the most CONSERVATIVE estimate I can find indicates brewed coffee contains AT LEAST 80mg/8oz; i.e. 338 mg/l.
If you ask Starbucks, it’s more like 240ml/12oz = 685mg/l.
Seriously: any reputable source. Go.
(and while you’re at it, at least have the balls to give a real email address…)