A study published last month in Nutrition Today finds milk is the most reliable source of calcium, superior to calcium-fortified soy and rice beverages and many orange juice brands. The study reveals that much of the calcium settles to the bottom of fortified soy and rice beverage containers, even after vigorous shaking. Researchers say that simply adding calcium to beverages does not make them nutritional substitutes for milk.

"The calcium that you'll find added to many soy beverages will have settled to the bottom of the container," said Robert P. Heaney, of the Osteoporosis Research Center at Creighton University, Omaha, Neb. "Hand shaking wasn't enough; we found that really vigorous shaking, such as with a hardware store paint shaker, would have been needed to suspend the calcium in these beverages so you can put them in the glass and drink them."

In this study, milk scored higher than all four soy or rice beverages, and eight of 10 orange juice products. Scores comparing calcium liquid suspension for two of the orange juice products were nearly the same as milk.