It's time to talk about vitamin B12: what it does, what foods contain it, and who might not be getting enough of it...

Here's the last installment of the Dietary Guidelines Nutrients of Concern series. Since the guidelines advise people to "Choose foods that provide more potassium, dietary fiber, calcium, and vitamin D, which are nutrients of concern in American diets," we've focused on discussing one of these nutrients per week. This week, we're going to talk about vitamin D...

Most Americans simply aren’t getting enough of certain vital nutrients, including calcium, dietary fiber, potassium, and vitamin D. Let's start with a closer look at calcium -- what it is, where to get it, what your body does with it, and what happens when you don't get enough...