Weak spots: Are you ruining your multivitamins?

Attention multivitamin mavens: Storing products in the wrong place can quickly degrade their healthful ingredients, according to a new study from Purdue University. In their evaluations, experts found that kitchens and bathrooms can be particularly problematic areas due to their extra heat and humidity. Plus, contrary to popular belief, tightly-sealed containers don't always help. "That's because opening and closing a package introduces humidity and moisture each time, changing the atmosphere within the container," explains Lisa Mauer, lead author of the study.

Over time, those steamy environs can cause nutrients like vitamin C and some forms of vitamin B to "deliquescence." That's a situation in which solid water-soluble nutrients begin to weaken and liquefy, she explains. As a result, unknowing consumers can experience a complete loss of ingredients. Multivitamins' nutrient delivery and shelf life can be destroyed, sometimes in as little as a week, Mauer says. Fortunately, keeping multivitamins away from warm, humid areas can help ensure their effectiveness.

How can you tell whether your multivitamin has already been affected? Check pills for brown spots and inspect their containers for traces of liquid or moisture, advises Mauer. If you see something suspicious, you should just discard the supplements. They're not necessarily unsafe, says Mauer, but why take a weakened product when you can consume something better? To sidestep future problems, store your vitamins in areas like your den or bedroom, which are likely to have more even temperatures.

For additional tips, check out our latest report on multivitamins.