Limit sweeteners. Usually, a children's vitamin needs to be sweet or else kids won't take it. Pick one sweetened with honey, fruit-juice concentrate, or molasses rather than high-fructose corn syrup, says Tara Skye Goldin, ND. Keep multis out of reach, though: If they look and taste like candy, kids may try to eat more than the daily dose.

Go natural. Avoid artificial flavors, preservatives, and colors—particularly red dye no. 40 and yellow dye no. 6, which have been linked to cancer in animal studies.

Read labels carefully.

Be complete. A multivitamin formulated specifically for children should contain at least 100 percent of the dietary reference intake (DRI) of folic acid, vitamins D, E, and C, and B vitamins. Because once-a-day multis usually don't provide the DRI of essential minerals such as magnesium, selenium, and calcium, which are too bulky to fit into one capsule, Shari Lieberman, PhD, FACN, recommends a separate multimineral supplement.