Which is an appropriate treatment for a nutritional anemia that presents as a hunger for ice and/or upward curvature of the fingernails?

The appropriate treatment for the described nutritional anemia, characterized by the craving for ice (known as pagophagia) and an upward curvature of the fingernails (koilonychia), is iron. These symptoms are often associated with iron deficiency anemia, which can arise from inadequate dietary intake of iron, chronic blood loss, or increased demand during periods such as pregnancy.

Iron is a critical component of hemoglobin, the molecule in red blood cells that carries oxygen. When there is an insufficient amount of iron, the body cannot produce enough healthy red blood cells, leading to fatigue, paleness, and other symptoms associated with anemia. The unique cravings and fingernail changes reflect the body’s attempts to cope with the deficiency.

While vitamin B12 and folic acid are important for other types of anemia, specifically those related to deficiencies in these vitamins (like megaloblastic anemia), they do not account for the specific symptoms presented in the question. Vitamin D is essential for bone health and calcium regulation, but it is not directly related to the treatment of anemia. Thus, iron stands out as the most appropriate and effective treatment option for the nutritional anemia described.