An A-Z guide to vitamins

What's riboflavin, and why am I taking 1.7 milligrams of it every day?

Americans spent more than $2.3 billion on vitamins and nutritional supplements last year, but the medical community still can't confirm that daily multivitamins are essential to health. What it can tell you, however, is that vitamins and minerals are important — and they're easy enough to get through foods.

"It's a good idea to have a fair amount of knowledge about your diet," says Paul Thomas, a scientific consultant with the Office of Dietary Supplements at the National Institutes of Health.

Thomas recommends paying close attention to official vitamin and mineral recommendations and watching your nutritional intake.

The attached PDF illustrates ways to find in nature what many daily supplements purport to provide. Print it out and keep a copy on your refrigerator.