Which of the following nutrient deficiencies can lead to glossitis?

Glossitis, which is characterized by inflammation and swelling of the tongue, can be linked to several nutrient deficiencies, with folate deficiency being one of the most significant. Folate is crucial for DNA synthesis and cell division, which are vital processes for maintaining the health of rapidly dividing tissues, including those in the mouth. When folate levels are insufficient, the turnover of cells in the tongue can be adversely affected, leading to glossitis.

In contrast, while other vitamins play important roles in overall health, they are not primarily associated with the condition of glossitis. Vitamin K is primarily involved in blood clotting, vitamin E acts as an antioxidant and is essential for immune function, and vitamin A is important for vision, immune function, and skin health. Although a deficiency in these vitamins can lead to other health issues, they do not significantly and directly contribute to the inflammation and symptoms seen in glossitis as folate does. Thus, the connection between folate deficiency and glossitis makes it the correct answer in this context.