Development of Goitre (enlarged thyroid gland) is mainly due to deficiency of

Goitre, characterized by an enlarged thyroid gland and a swollen neck, is primarily caused by a deficiency of iodine in the diet [c1][t1]. Iodine is a trace element essential for the synthesis of thyroxin (thyroid hormone) [c1][t1]. When iodine levels are insufficient, the thyroid gland cannot produce adequate hormones, leading to a group of conditions known as Iodine Deficiency Disorders (IDD) [t1][t2]. To compensate for the low hormone production, the pituitary gland stimulates the thyroid, causing it to enlarge into a goitre [t10]. Globally, iodine deficiency is the most common cause of goitre, though it is less prevalent in regions where universal salt iodization is implemented [t6][t10]. Other options like iron deficiency lead to anemia [c3], while calcium and sodium are not directly linked to the development of goitre.

Sources

1. [1] Science , class X (NCERT 2025 ed.) > Chapter 6: Control and Coordination > Do You Know? > p. 110
2. [2] https://www.healthdirect.gov.au/iodine-deficiency
3. [3] https://www.ncbi.nlm.nih.gov/books/NBK285556/
4. [4] Science-Class VII . NCERT(Revised ed 2025) > Chapter 6: Adolescence: A Stage of Growth and Change > Science and Society > p. 80