The method in which juice manufacturers deal with folic acid loss may be creating a potential health risk.
Because folic acid is highly sensitive in nature, manufacturers often add extra folic acid to their products in order to guarantee over time what’s listed on their nutrition facts panels. But extra folic acid isn’t necessarily safe for consumers. In fact, researchers have warned that it can mask vitamin B12 deficiency in humans. Is fortification with this nutrient, then, appropriate for all products?
Researchers at the Max Rubner-Institut in Germany aren’t so sure. With vitamin juices, folic acid is exposed to a small amount of oxygen (the empty space inside the top of the bottle), low pH (typical of most vitamin juices), and, depending on the packaging, light. These conditions can all degrade folic acid, and they surely did in a test on folic acid in vitamin juice.
Reporting their results in Food Chemistry, researchers analyzed the effects of one year’s storage time on nine popular vitamin juices sold in Europe and fortified with folic acid. Each juice was kept at 18°C to reflect supermarket refrigeration, and each was kept in both dark and light storage environments. Over time, juices displayed an average 46% loss in folic acid (81 µg/ml). The degradation was even worse when juices were exposed to light. Folic acid appeared to degrade quickest during the first six months of storage, and this is “presumed to be due to reaction with oxygen (dissolved or present in the heat-space of the package) which will eventually be exhausted.” Also, fresh juices were more susceptible to folic acid loss than non-fresh juices.
As expected, juice manufacturers added extra amounts of folic acid to all of these juices. With the loss of folic acid over time, though, juices still exceeded their declared label amounts. Consumers may be in danger of exceeding tolerable upper intake levels of 1 mg of folic acid/day as established by the European Food Safety Authority.
Nutritional Outlook magazine
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