On white rice...
The milling and polishing processes both remove important nutrients. A diet based on unenriched white rice leaves people vulnerable to the neurological disease beriberi, due to a deficiency of thiamine (vitamin B1). White rice is often enriched with some of the nutrients stripped from it during its processing. Enrichment of white rice with B1, B3, and iron is required by law in the United States, although these nutrients are only a small portion of what has been removed.
At various times, starting in the 19th century, brown rice and wild rice have been advocated as healthier alternatives. The bran in brown rice contains significant dietary fiber and the germ contains many vitamins and minerals. (See whole grain.)
This is why I'm glad Chipotle now offers brown rice.