THURSDAY, August 4, 2011 (Health.com) — Coconut water, which came to fame as a celebrity health fad, has become an increasingly popular way to stay hydrated or recover after a workout. Filled with electrolytes like sodium and magnesium, the slightly sweet water has come to be seen as a natural alternative to sports drinks like Gatorade.
That reputation may not be entirely deserved. According to a report released today by an independent health-product testing firm, the nutritional content of some brands of coconut water doesn't live up to what's on the label.
Researchers at ConsumerLab.com tested the sodium, potassium, magnesium, and sugar content of three leading brands of coconut water, and they found that only one brand, Zico Natural, contained the stated amount for all four ingredients.
The sugar and potassium content in the other two brands, Vita Coco and O.N.E., also matched the label. But the amounts of sodium and magnesium—two nutrients key to hydration—were as much as 82% and 35% lower, respectively, than the listed amount.
Since the electrolyte content is one of the main selling points of these drinks, thirsty consumers may not be getting what they paid for, says Bonnie Taub-Dix, a registered dietitian and spokesperson for the American Dietetic Association.
"When something like this becomes wildly popular, people have a tendency to look at the claims rather than reality," says Taub-Dix, the author of Read It Before You Eat It. "If you're working out and sweating a lot, this isn't going to do the trick."
Taub-Dix recommends hydrating with water instead and getting nutrients like sodium and potassium from foods such as bananas and almond butter. And unless you're running a marathon or climbing mountains, she adds, you probably don't need a sports drink.
Tod Cooperman, the president of ConsumerLab.com, says the growing popularity of coconut water got the company's attention and prompted the testing. "This was really the first look into what’s really in these bottles and whether or not they live up to their claims," he says.
"If you enjoy the taste of coconut water, they’re fine, but I wouldn’t rely on them for rehydrating after strenuous exercise," he adds.
Arthur Gallego, the director of communications for Vita Coco, said in a statement that he could not comment specifically on the report, as the company has not thoroughly reviewed it.
He noted, however, that Vita Coco is derived from coconuts grown in multiple locations in Brazil and Southeast Asia, and that the individual cartons tested by ConsumerLab.com aren't necessarily representative of Vita Coco's average nutritional content.
The company routinely conducts its own tests, and some variation in electrolytes between batches (or lots) is normal, he added.
The Food and Drug Administration (FDA) does not test the nutrient content of foods itself, and the agency does not specify how companies should do so. Nor do they do prohibit food and drink manufacturers from using average values if the nutrient content varies from batch to batch, as long as "a manufacturer is confident that the values obtained meet FDA's compliance criteria."
The test results don't mean that consumers should pass on coconut water altogether. Though some cartons may contain lower-than-expected electrolyte levels, the drinks are a healthy, low-calorie alternative to soda or fruit juice, Taub-Dix says.
"If you're looking to cut your calories and looking for something tropical, sure, but when it comes to hydration, it may not work as well as some other fluids," she says.