Four 'Enhanced' Water Drinks You Can Skip

Bottled water isn't any better for you than tap water in American cities—and even the bottled water industry won't argue the point. But what about the new "enhanced" waters containing vitamins and herbs? Their snappy names and lists of additives do imply health benefits beyond the goal of staying well-hydrated. Unfortunately, the science behind them is weak, according to the Center for Science in the Public Interest, an advocacy group for information on nutrition. So before you load the cooler with pricey vitamin-enhanced waters, consider filling up empties at the tap instead. There are better ways to relax, get refreshed and boost your immunity than by downing the enhanced waters below:

1. Calming Waters? Coca Cola's VitaminWater B-Relaxed Jackfruit-Guava contains several vitamins B and theanine, a natural ingredient in tea, along with 125 calories' worth of sugar per bottle. According to a Coca-Cola spokesperson, theanine levels of 50 mg to 200 mg have been shown to stimulate the "production of alpha brain waves, which are associated with a relaxed state of mental alertness." A 20-fluid-ounce bottle contains 50 mg of theanine, compared to 20 mg in a cup of tea. Coca-Cola also notes that the vitamins B in its product help the body fight stress. However, there is no evidence those vitamins are experienced as calming, says CSPI. And according to the most recent study of theanine, reported in the journal Psychopharmacology, it also does not affect mood. (Theanine does counter temporary rises in blood pressure caused by caffeine.) Buyers note: Despite the name, the product does not contain actual jackfruit or guava, only flavors.

2. Can Water Stave Off Colds? Coca Cola's Dasani Plus Defend + Protect contains zinc and vitamin E, two substances that play a role in immunity. However, according to the CSPI, research suggests that taking vitamin E boosts immunity only if it is consumed in very large amounts by older people who are deficient in the vitamin. Some evidence suggests that zinc lozenges may shorten colds. But that doesn't mean drinking zinc in water will, says CSPI, and, as Coca-Cola points out, there aren't any studies "using water fortified with zinc to determine the effect on colds."

3. Getting Tough on H20? Pepsi-Co's Sobe Life Water Challenge Your Life provides taurine, sometimes touted as a muscle strengthener, and ginseng, believed to boost alertness. The science: Participants in one study took 20 grams a day of taurine for seven days, and did a pushup test before and after. Taurine didn't make them any better at pushups. As for ginseng, the evidence that it boosts alertness is inconsistent, says CSPI—in fact, it appears to reduce alertness under some circumstances. Dosages count. But the Sobe label doesn't say how much taurine or ginseng is in its product, and Sobe did not provide the information to Newsweek when asked. A spokeswoman says, "We allow customers to decide what 'challenge' means to them."

4. Fiber Water? Pepsi-Co's Aquafina Alive Satisfy does contain maltodextrin, which qualifies under the government definition of fiber. However, it's a soluble fiber, so it won't keep you regular like the fiber in grains and beans.