Companies are increasingly adding vitamins and minerals to juices, sports drinks and bottled water, responding to a growing consumer demand for these products. Even though the amounts of added nutrients in these drinks are typically small, some nutrition scientists are concerned that through their overall diets, many people may be ingesting levels of vitamins and other nutrients that are not only unnecessary, but potentially harmful, reports The New York Times.
"You have vitamins and minerals that occur naturally in foods, and then you have people taking supplements, and then you have all these fortified foods," said Mridul Datta, an assistant professor in the department of nutrition science at Purdue University. "It adds up to quite an excess. There’s the potential for people to get a lot more of these vitamins than they need." Today more than ever, studies show, the average person is exposed to unusually high levels of vitamins and minerals. Already, more than half of all adults in the US take a multivitamin or dietary supplement. Bread, milk and other foods are often fortified with folic acid, niacin and vitamins A and D. A study published in July, 2014 found that many people are exceeding the safe limits of nutrient intakes established by the Institute of Medicine. And research shows that people who take dietary supplements are often the ones who need them the least.
Particularly concerning, experts say, is the explosion of beverages marketed specifically for their high levels of antioxidants, like Vitaminwater, POM Wonderful, Naked Juice and many others. The body requires antioxidants to neutralise free radicals that can damage cells and their DNA. But it also uses free radicals to fight off infections and cancer cells, experts say, and when antioxidants are present in excess, it can throw things out of balance.
A recent study analysed 46 beverages – both with and without sugar – sold in supermarkets alongside bottled water. It found that many of these drinks contained vitamins B6, B12, niacin and vitamin C in quantities "well in excess" of the average daily requirements for young adults. Eighteen of these drinks contained more than triple the daily requirement for B6. Eleven had more than three times the requirement for B12. And a half dozen had more than three times the requirement for niacin or riboflavin. Some of these products promised improvements in energy and immune function, while others promoted "performance and emotional benefits related to nutrient formulations that go beyond conventional nutritional science," the researchers said.
The most common nutrients added were vitamins that are already plentiful in the average person’s diet, so their widespread inclusion in these drinks is almost completely unnecessary, said Valerie Tarasuk, the lead author of the study and a nutrition science professor in the faculty of medicine at the University of Toronto. "It's very hard to figure out the logic the manufacturers are using to do this fortification," she said. "There's no way that the things that are being added are things that anybody needs or stands to benefit from."
Added vitamins may clearly aid some people, including women who are pregnant or lactating, or those with specific nutritional deficiencies. But for much of the general population today, there is no scientific justification for a high intake of vitamins and minerals, said Mara Z. Vitolins, a registered dietician and professor of epidemiology and prevention at Wake Forest Baptist Medical Centre. When consumed in excess, some water-soluble vitamins like B and C are excreted in the urine. But fat soluble-vitamins – including A, D, E and K – accumulate in tissues, posing potential risks. "These fat soluble vitamins are very stable," she said. "They're 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. You have to be very careful with them."
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