With everyone looking to get a little healthier these days, the "superfood" business thrives. Super fruits seem to be able to do it all -- combat heart disease, cure erectile dysfunction, remedy chronic fatigue syndrome, guide you to the Promised Land. OK, maybe that last one was made up. But there is often little research to back up what's on the labels.
Last week, researchers at ConsumerLab.com tested three major brands of coconut water, Zico Natural, Vita Coco and O.N.E. for potassium, sodium, magnesium and sugar content. Only ZICO Natural contained the stated amount of all four ingredients listed on its packaging.
"The recent study about coconut water only proves what ZICO has been claiming all along—our coconut water provides all-natural health benefits and keeps athletes properly hydrated to help them reach peak performance," said ZICO Coconut Water CEO Mark Rampolla.
In an interview with ABCNews.com, Michael Kirban, CEO of Vita Coco, defended his product, noting that Vita Coco and O.N.E. are natural products, while Zico Natural is from concentrate, which allows researchers to include an exact amount of each ingredient.
"We see fluctuations, both positive and negative, by about 10 to 15 percent," said Kirban. "The FDA allows for up to a 20 percent variant from the stated amount. We're never going to be exact with a natural product."
O.N.E. CEO, Rodrigo Veloso, made a similar point.
"Other similar products, made from concentrate, may be engineered to cause for less variation than going directly from the freshly harvested coconut to the package," Veloso said in an emailed statement. "Nonetheless, O.N.E. is taking the claims seriously and is thoroughly investigating the accuracy and validity of the claims made in the report."
Coconut water is only the most recent fad drink to hit the shelves. With its potassium and hydrating benefits, many people, especially those who value a good workout, have been drawn to it.
Many superfruits boast high amounts of antioxidants, which help fight free radicals that damage or kill cells. Studies found that people who eat a diet high in antioxidants have a lower risk of heart disease, cancer and several other diseases. No one is arguing that these foods don't bring health benefits, but many wonder if they have any more than the standard berries in your grocery store.
"Consumers are always searching for the quick fix -- the magic answer -- and I suspect, for something different," said Connie Diekman, director of university nutrition at Washington University in St. Louis. "The problem is that magic answers to health don't exist. It is all about our overall approach to eating, activity and lifestyle."
So, here, without further ado, are seven of some of the most popular "superfoods" in stores today.
While different brands of coconut water welcome consumers with their tropical packaging, experts say there is very little research to prove that there is anything particularly magical about the drink.
"It is high in protein, doesn't have a lot of taste and does not contain a huge amount of ... plant nutrients," said Leslie Bonci, director of sports nutrition at University of Pittsburgh Medical Center. "Unlike most juices, which are low in sodium, coconut water has 252 mg per 8 ounce serving. Coconut water does contain phytohormones, which have antioxidant and anti-platelet properties, so there may be health benefits, but it is very expensive."
But there is one benefit that's hard to argue against.
"Coconut water is low in calories," said Keith Ayoob, associate professor of pediatrics at Albert Einstein College of Medicine in New York. "That's a real plus, because it's very easy to overconsume beverage calories."
In 2009, this dark purple fruit blew up in popularity after Dr. Oz highlighted the lovable berry on "Oprah" as one of the secrets on her "mac daddy" anti-aging checklist. Oz told the crowd that acai berries contain twice the antioxidant content as in blueberries. Several juice companies market the fruit as one that helps prevent heart disease, cancer, aging, and encourages weight loss, just for starters.
But in 2009, the Center for Science and Public Interest warned consumers that there is no evidence that the Brazilian berry helps anyone shed pounds, and discouraged people from enrolling in the online, supposedly free, clinical trials for the product that were popping up on Internet ads and email listserves.
"I do think people hear the words tropical rain forest, and assume this is better than what they can find in the grocery store," said Bonci. "Yes, acai does contain antioxidants and phytonutrients, and also contains polyunsaturated fats and fiber, as well as anthocyanins. However, the anthocyanin content of grapes or blueberries is higher, and these fruits are less pricey."
While not as popular as the acai berry, mangosteens are enjoying popularity as a fruit-turned-juice, for which companies tout benefit claims of anti-fatigue, anti-obesity and anti-depression. The mangosteens come from tropical evergreen trees in the Pacific and contain a high concentration of antioxidants.
"Mangosteens are high in polyphenols, a type of antioxidant, and so they have anti-inflammatory properties, but so do more common berries," said Ayoob.
Bonci agreed, noting that it is also high in xanthones, another type of antioxidant.
"[There] may be some application with regards to inflammation, insulin resistance, cancer prevention or slowing cancer progression, and immune system boosting, but there are not a lot of studies, and like the other juices, said Bonci. "This is still very costly."
Similar to the acai's popularity, the pomegranate has gained ground as a superfood high in antioxidants. "Preliminary evidence indicated some health benefits from pomegranate juice, but as research has evolved, the evidence does not support it being any better than any other darkly colored, strongly flavored fruit or vegetable," said Diekman.
While the pomegranate is an excellent source of antioxidants, like many of the other fruits mentioned, it carries another heavy price tag.
"The price of pomegranate juice is double what grape juice is, and the health benefit is similar," said Bonci.
This little red fruit, also known as a Chinese wolfberry, looks similar to a cherry tomato. Native to southeastern Europe and Asia, many marketers of goji berry supplements and juice claim the fruit can stave off diabetes, high blood pressure and age-related eye problems.
But the berries come with a hefty price tag.
"They cost about $30 for an 18 ounce bag and, although they may have health benefits, the [cost] may outweigh the health value," said Bonci. "Also, some goji juices contain tiny amounts of goji berries and lots of sugar, so what you think you are getting, you may not be."
The noni fruit, not nearly as popular as its other superfood counterparts, is native to Southeast Asia and Australasia. It is marketed as a juice that supports the immune system and heart health and increases energy.
Bonci noted that the noni fruit contains high amounts of vitamin C and potassium. But so high "that it may be problematic for those with kidney disease." She even noted that a study published in the Canadian Journal of Herbalism suggested that noni may be a highly addictive narcotic painkiller.
"These are [all] good nutrient sources, but none of them can compensate for a diet that isn't good overall," said Dr. David Katz, director of the Yale Prevention Center. "There is no evidence of health benefit linked specifically to the intake of any of these."
Wheatgrass, often consumed as "shots" in smoothies and healthy shakes, comes from the common wheat plant known as Triticum aestivum. The food contains B vitamins, beta-carotene, vitamin C and potassium. Marketers claim that consistent consumption of the product cleanses the body and slows the aging process.
It's certainly a healthy food, "but you would need to consume a lot of wheat grass to equal what you might get in a spinach salad," said Bonci.
"These juices, and the many more that will flood the market in the future, can fit into a healthful eating plan as long as they are not over-consumed ... and that they are a part of an eating plan that focuses on more fruits, vegetable, whole grains and lean meat and low-fat dairy," said Diekman.
With that said, Diekman encourages people to eat whole fruits instead of the juice and supplement alternative when experts do not fully understand their overall health benefits.
"It's hard to resist the lure of the silver bullet," said Katz. "We probably all really know that good health requires a real commitment of eating well [and] being active. ... Marketers know we want this kind of magic, and so they do a very good job of suggesting their product provides it."