The most common nutritional deficiency worldwide is:

Step 1: Understand the question. The question asks to identify the most common nutritional deficiency worldwide. Step 2: Recall major global nutritional deficiencies. Common global nutritional deficiencies include iron deficiency, vitamin A deficiency, iodine deficiency, and zinc deficiency. Step 3: Determine the most prevalent one. According to global health organizations such as the World Health Organization (WHO), iron deficiency is the most widespread nutritional deficiency globally, affecting a significant portion of the world's population, particularly women and children. It is the leading cause of anemia. The most common nutritional deficiency worldwide is Iron deficiency. Iron deficiency 3 done, 2 left today. You're making progress.