Use of polished rice in human diet causes which of the following diseases?

Beriberi is caused by deficiency of thiamine (vitamin B1). Thiamine is concentrated in the bran and outer aleurone layers of the rice grain, and milling and polishing remove these layers. Where polished rice is the main staple with little else in the diet, thiamine deficiency follows, damaging nerves, the heart and muscles. Parboiling helps because it pushes vitamins from the bran into the grain before milling.

• Goitre is due to iodine deficiency affecting thyroid hormone synthesis. Rice milling has nothing to do with it; iodised salt is the remedy.
• Night blindness is due to vitamin A deficiency, needed for rhodopsin in the retina. It is a dietary problem linked to low intake of vitamin A or its precursors, not a specific effect of polishing rice.
• Colour blindness is an inherited condition, mostly X-linked, affecting cone pigment genes. No diet causes it.

The core concept is micronutrient loss through food processing, which links to the Health and Nutrition section of the syllabus. For Mains, it connects to nutrition security and the fortified rice initiatives under government schemes meant to address hidden hunger.

Trap: aspirants often pick night blindness because polished rice is linked to vitamin deficiency in general. Remember that the milling-specific deficiency is thiamine, which causes beriberi.