I would like to add a precaution before suggesting zinc supplementation to anyone with nutritional growth retardation who lives in places where zinc deficiency may be prevalent. Iron deficiency which may co-exist with zinc deficiency may be aggravated during zinc therapy because these two minerals may block the intestinal absorption of each other.¹ Consequently, iron deficiency may also worsen growth retardation. Therefore, I suggest excluding iron deficiency, which is easier to diagnose than zinc deficiency, before initiating zinc supplementation.

Reference

1.    Lifshitz F, et al. Nutritional Growth Retardation. In: Lifshitz F, ed. Pediatric Endocrinology 3^rd Edition. New York: Marcel Dekker, 1996:103-120.