Did you know that whole grains provide much more nutrition than just dietary fiber? Whole grains are also an excellent source of B vitamins, iron, zinc, potassium, magnesium and antioxidants such as vitamin E. Some whole grains are not brown, and some brown breads are not whole grain. So don’t go by color alone. Instead, look for the word 'whole’ before the type of grain in the ingredient list, like whole wheat or whole oats. The U.S. Dietary Guidelines recommend that at least half of the grains we eat each day should come from whole grains.
Source: U.S. Dietary Guidelines for Americans