Scientists are concerned vitamin drinks are contributing to levels of vitamins and other nutrients that are not only unnecessary, but potentially harmful.
Vitamins and minerals occur naturally in foods, but people get more through vitamin supplements and “fortified foods,” said Mridul Datta, an assistant professor in the department of nutrition science at Purdue University. “It adds up to quite an excess,” Datta said. People can ingest more of these vitamins than they need, The New York Times reports, and excess amounts of some nutrients can prove harmful rather than beneficial.
Vitamin-enhanced beverages and sports drinks account for more than $18 billion a year in sales in the United States alone.
The Times reports that more than half of all adults take a multivitamin and common foods like bread and milk are fortified with folic acid, niacin and vitamins A and D. A study published last summer in Critical Reviews in Food Science and Nutrition found that many people are exceeding the safe limits of nutrient intakes established by the Institute of Medicine. Experts are particularly concerned with the proliferation of beverages with high levels of antioxidants, like Vitaminwater, POM Wonderful, Naked Juice and others. While antioxidants are necessary to neutralize free radicals that can damage cells, excessive antioxidants can throw off the body’s balance.
Experts point to risks from excess levels of some nutrients. A 2009 study in JAMA found that heart patients who were given folic acid and vitamin B12 had higher mortality and cancer rates. And a 2012 review of 78 clinical trials involving 300,000 found that antioxidant supplements like beta carotene, vitamin A and vitamin E actually increased mortality, according to the Times. The United States Preventive Services Task Force concluded that there was “limited evidence” that taking vitamins and minerals could prevent cancer and cardiovascular disease. Mara Z. Vitolins, a registered dietitian and professor of epidemiology and prevention at Wake Forest Baptist Medical Center, said fat-soluble vitamins are not released in the urine. “If you are over-consuming them, you can raise your levels gradually over time and get into trouble with liver function.”
A recent study published in Applied Nutrition, Physiology, Nutrition and Metabolism, analyzed 46 beverages. Many of the drinks contained vitamins B6, B12, niacin and vitamin C in quantities “well in excess” of the average daily requirements for young adults, the Times reports. Eighteen contained more than triple the daily requirement for B6, and 11 had more than three times the requirement for B12. Some of the drinks promised increased energy and improved immune function, while others promoted “performance and emotional benefits related to nutrient formulations that go beyond conventional nutritional science,” the researchers said.