Health and sports drinks like Vitaminwater and Naked Juice pride themselves for containing high amounts of vitamins or nutrients. But a new study finds that many of these beverages often have excessive amounts of vitamins, sometimes in harmful dosages.

A study published in the journal Applied Physiology, Nutrition, and Metabolism looked at 46 drinks sold next to bottled water in grocery stores. Researchers found that 18 of the drinks had three times the recommended dosage of B6, and 11 had three times the suggested amount of B12.

In general, the study noted, the vitamins often included in sports drinks include vitamins plentiful in the average person’s diet, making the need to add some vitamins in drinks somewhat unnecessary. Combined with multivitamin supplements, excessive vitamin intake can add up. In some cases, the body will simply eliminate vitamins if there are too many, but for others too much can be harmful.

“When consumed in excess, some water-soluble vitamins like B and C are excreted in the urine,” a New York Times article explained. “But fat soluble-vitamins — including A, D, E and K — accumulate in the tissues, posing potential risks.”

Consuming an excessive amount of vitamins by eating natural food is nearly impossible, but some vitamin drinks have the recommended amount, some even more, of particular vitamins, including Vitaminwater’s Formula 50, which includes 120 percent of the recommended amount of Vitamin C, B6 and B12.