In late 1800s and early 1900s, several pockets of populations from Indian sub-continent (and other parts of the world) suffered from beri beri epidemics. It took several decades to identify and acknowledge that the root cause of beri beri was polished rice! For a detailed history, please browse through British India and the Beri Beri Problem: 1798 - 1942 by David Arnold, published in Medical History, 54(3):295, July 2010. This article explains that one of the factors that contributed to slowness in acknowledgment was that polished rice export from India was a lucrative business in early 1900s.

Over the years, science has progressed and we have pin-pointed a specific component: Vitamin B1 is lacking in polished rice. So there are government guidelines to fortify polished rice with B1 (and a few other micro-nutrients).

Today, do governments have laws that refined grains must be 'fortified'? Yes. In other words, we must re-introduce some micro-nutrients whose absence makes refined grains nutrition-deficient. For example, Scaling Up Rice Fortification in Latin America and the Caribbean, WFP 113 by World Food Programme explains:

How many micronutrients are lost in brown rice with bran and germ removal? And how may we re-introduce some of the minerals through fortification? Whole Grains Council has a diagram:

… but did we re-introduce everything through fortification? No. Only a few specific micronutrients. Much fiber is lost. Several other micronutrients are also lost.