I’m a runner, and have been actively running for over a decade. Since I started running, I’ve consumed Gatorade Lemon-Lime almost exclusively as my as my rehydration fluid of choice. Whenever my run will last over about an hour, I carry and consume Gatorade to offset fluid loss and give me some carbohydrate. The formulation is basic: sugar, salt, and potassium. There are a hundreds of electrolyte products out there, and even Gatorade makes versions with exotic ingredients now. But I’ve been faithful to the original: It’s cheap, I don’t mind the taste (even when its warm), you can buy it nearly anywhere, and it’s a common beverage (besides water) offered at races. Plus, I’ve never been that convinced that it matters all that much – I focus on the engine, not the fuel. After exercise I usually stick with water, preferring to get my electrolytes and carbohydrates from food, rather than liquid sources. But now I’m seeing advertising me that sports drinks are both artificial and inferior. Is it time to upgrade my fuel?
Coconut water isn’t just at the West Indian roti shop anymore: From the grocery store to the yoga studio to the running club, it’s everywhere. The excellent Planet Money podcast recently did a feature on the skyrocketing sales of coconut water, so I decided to take a closer look. Is coconut water a fad beverage, like Vitamin Water was last week, and pomegranate juice the week before?It’s positioned as a superior product for rehydration. The marketing and packaging rely heavily on the naturalistic fallacy, and it’s clearly an appeal to nature: Coconut water naturally contains sugars and electrolytes. Natural is better than unnatural, therefore coconut water is a better beverage choice. Or is it?
What’s in coconut water?
Don’t confuse coconut water with coconut milk, which contains a lot of coconut “meat”, the white solid we might refer to simply as coconut. Coconut water is the 2-4 cups of fluid inside a young coconut, which declines as the “meat” grows. Depending on when the water is withdrawn, the electrolyte levels may vary, but have been reported in the following ranges [PDF]:
- sodium 0.7-0.9 mEq/L
- potassium 35-82 mEq/L
- glucose 1.2-2.8 grams/L
- calcium 5-17 mEq/L
- magnesium 5-25 mEq/L
There are also small amounts of amino acids, vitamins and minerals present. Compared to a beverage like Gatorade, there’s more potassium, and less sodium and sugar. And unlike Gatorade, coconut has even been directly injected into veins.
Rehydration
The science of treating dehydration has been well evaluated – particularly in the treatment of diarrhea. In most cases, mild diarrhea is a bother. Severe, sustained diarrhea, however, particularly in children, can become life threatening without treatment. Diarrhea kills millions in the third world each year, mainly children under the age of 5. The treatment is simple, but not always available. The World Health Organization’s Oral Rehydration Solution (ORS), which is 6 level teaspoons of sugar and 1/2 level teaspoon of salt dissolved in 1 litre of water, is the considered optimal ratio of sugar and salt to support rehydration. Why sugar and salt in the water? It’s because plain water is not absorbed as well as a solution of salt and sugar. The journal The Lancet called this discovery “potentially the most important medical advance of this century.” The concentration of sugar and sodium will impact on how effectively a beverage will hydrate. How effectively are do the concentrations in a coconut support rehydration? Poorly. Coconut water appears to be inferior for hydration caused by diarrhea.
So is this information relevant to exercise-induced dehydration? Here there have been some preliminary studies as well. I found three relevant to the question.
- Coconut water was compared to a carbohydrate/electrolye beverage, and plain water, in subjects who exercised in the heat. After exercise subjects drank 120% of their fluid loss. There was no significant difference in the amount of hydration achieved, electrolyte levels, or fluid balance.
- Another study compared plain water, sports drink, coconut water, and sodium-enriched coconut water. Again, subjects exercised in the heat and then rehydrated with 120% of their fluid losses. Here, sports drink and both coconut waters rehydrated to a similar extent and all were slightly superior to water. The sodium-enriched coconut water was reported as better tolerated than other beverages.
- Finally, in an article just published, Comparison of coconut water and a carbohydrate-electrolyte sport drink on measures of hydration and physical performance in exercise-trained men, coconut water was compared with sports drink and plain water, following exercise-induced dehydration. Yet again, no differences were noted between groups.
So what’s best?
There’s no convincing evidence to suggest that coconut water is a superior beverage for hydration. Coconut water has no magical properties which make it more effective or superior than water or sports drinks. Having said that, many love the taste of coconut water. As a low calorie option, it may be preferred by some over carbohydrate-containing sports drinks. Or you can stick with zero-calorie water, and eat something to replenish electrolytes. Coconut water or any other beverage, it doesn’t seem to matter for hydration.
Photo from flickr user iateapie under a CC licence.
Science-Based Pharmacy 
Most of the people I see buying coconut water do not look as though they exercise much at all, let alone RUN. I used to run, but not at a level that ever dehydrated me. Plain water was always sufficient. I never even heard of exercise induced diarrhea, let alone suffered from it! One sip of Gatorade was enough to make me vomit, however–disgusting stuff!
I know a lot of altie types and this coconut water thing is just the latest, “natural is better” hype and any number of “magical” claims are being made for it. They’re all drinking it after yoga class now. I got a massage a while back, and she wanted me to drink a whole bottle of the stuff to “resplenish” the water that went out with the “toxins”.
Trouble is, your reporting won’t phase them at all–they think they are privy to “secrets” that you “allopathic” types are just too corrupted by “BigPharma” to understand. But reasonable people are glad to know of these studies by all means, so thanks!
I haven’t heard of exercise-induced diarrhea, either. Could be that Scott meant exercise-induced dehydration?
Scott – is the recipe listed for the home-made ORS there making something closer to the old ORS, or the new low-osmolarity ORS? Curious, because I know the testing showed the new version to be better at least in sever diarrhea, and I was wondering if the recipe had been updated (if not, it’d just need a little less salt and a couple fewer teaspoons of sugar)
Thanks for this article. I’ve been drinking coconut water for a few years now (pre-fad, I guess), as due to my illness and meds I get dehydrated very easily. In this particular case I do find “natural is better” because Gatorade tastes to me like a chemical waste smoothie & Pedialyte isn’t much better. As you say, coconut water just tastes better to me, which is “magic” enough. Especially if I’ve just vomited, it’s a very light and mild way to get some electrolytes back. If it works just as well as Gatorade, that’s very good to know, and plenty good enough for me. I encourage skeptics to ignore the woo surrounding coconut water and enjoy it, since the fad doesn’t diminish its actual, modest benefits.
I’m not a long-distance runner, so water pretty much meets my rehydration needs most of the time. If I do drink Gatorade, I usually dilute it 50%. I’ve also made up the ORT formula for events where I knew dehydration was a risk, and added some other flavoring (typically, ginger. Cause I like the taste).
And I prefer the taste of coconut water to, say, Gatorade, but I prefer the cost of Gatorade to coconut water.
Exercise induced *dehydration*. Fixed.
It can be confusing and misleading to broadly apply the naturalistic fallacy to health claims in this way. Making a distinction between whether a product is derived from nature or has been consumed by people for a very long time safely, and is therefore natural to consume, is important. Of course, the marketers of natural products do not often make this distinction, but scientists can and should. It is certainly clear that it is a fallacy that something that is natural is therefore efficacious and safe, but if something has been consumed safely historically, then it probably is safe. Historical fallacy? The onus is really on the seller of new products that have never been consumed by humans before to demonstrate safety. Granted, helpful empirically-derived indicators like LD50 are not derived from historical record, nor is mechanism, but scientific studies will always struggle to encapsulate the duration of historical record, no? Your use of the phrase naturalistic fallacy is vague in a similar way to the use of “natural” by marketers, in that, marketers use natural to mean good, but you use natural to mean untested.
What do you think? I think there is a historical fallacy of efficacy in the absence of scientific study, but historical observation counts for something and has served as a starting point for formal scientific inquiry historically 😉