From Dr. Fuhrman's book Eat to Live:
White or "enriched" rice is just as bad as white bread and pasta. It is nutritionally bankrupt. You might as well just eat the Uncle Ben's cardboard box it comes in. Refining removes important factors: fiber, minerals, phytochemicals, and vitamin E. So, when you eat grains, eat whole grains.
Refining foods removes so much nutrition that our government requires that a few synthetic vitamins and minerals be added back. Such food is labelled as enriched or fortified. Whenever you see those words on a package, it means important nutrients are missing. Refining foods lowers the amount of hundreds of known nutrients, yet usually only five to ten are added back by fortification.
As we change food through processing and refining, we rob the food of certain health-supporting substances and often create unhealthy compounds, thus making it a more unfit food for human consumption. As a general rule of thumb: the closer we eat foods to their natural state, the healthier the food.