Use of polished rice in human diet causes the following disease

Question

UnlockIAS · Accepted Answer

Correct — A, Beriberi. Milling and polishing strip the bran and germ off the rice grain, and it is precisely those outer layers that hold most of the grain's thiamine (Vitamin B1); the starchy endosperm left behind is nearly thiamine-free. A diet built around polished white rice with few other B1 sources therefore produces chronic thiamine deficiency, whose classical clinical form is beriberi. It appears in two patterns — 'wet' beriberi, which attacks the cardiovascular system and causes oedema and high-output heart failure, and 'dry' beriberi, which damages peripheral nerves and causes tingling, weakness and wasting of the limbs; infantile beriberi occurs in breastfed babies of thiamine-deficient mothers. This is one of the oldest established nutrition links in medicine: Christiaan Eijkman showed in the 1890s that fowls fed polished rice developed a polyneuritis that was cured by the discarded bran, work that led to the concept of vitamins and to his Nobel Prize in 1929.

Why the other options are wrong — (b) Goitre — visible enlargement of the thyroid gland — is caused by iodine deficiency, not by any vitamin. Iodine is a mineral supplied mainly by iodised salt, seafood and soils; it has nothing to do with how a rice grain is milled. India's response to it was universal salt iodisation, not rice policy.  (c) Night blindness is the earliest sign of Vitamin A (retinol) deficiency: without retinol the rod cells of the retina cannot make enough rhodopsin to see in dim light, and severe deficiency progresses to xerophthalmia. It is a real diet-linked disease, which is why it sits here, but it is the wrong vitamin — A, not B1.  (d) Colour blindness is not a nutritional disorder at all. It is an inherited X-linked recessive condition affecting the cone pigments — which is why it is far commoner in males — and no change of diet causes it or cures it. It is the odd one out and can be eliminated on principle before any vitamin is recalled.

Concept: A rice grain has three edible parts: the fibrous bran coat, the nutrient-dense germ, and the starchy endosperm. Milling removes bran and germ to give white rice that stores longer and cooks whiter, but it takes away most of the grain's thiamine, other B vitamins, minerals and fat. Thiamine is a water-soluble vitamin the body stores only in small amounts, so a deficient diet shows up in weeks to months. It works as the coenzyme thiamine pyrophosphate in carbohydrate metabolism, which is why the tissues that fail first are the ones most dependent on steady glucose oxidation — heart and nerve. Thiamine deficiency also underlies Wernicke–Korsakoff syndrome, seen chiefly with chronic alcohol use.

State PCS 2019 Q85 — Science & Technology PYQ with Answer

State PCS 2019 Q85 — Science & Technology PYQ with Answer