There is a type of wheat called white wheat that is used to make those breads. It is a different type of wheat that has no major genes for bran color unlike traditional “red” wheat. An easy way to think of it is as a sort of albino wheat. The bread is simply made with whole white wheat flour, including the bran, germ and endosperm. The bran of white wheat is not only lighter in color but it’s also milder in flavor, making whole white wheat more appealing to many people accustomed to the taste of refined flour.

Additional Resources:

http://www.mayoclinic.com/health/whole-wheat-bread/AN01512