Which nutritional deficiency may cause the inability to bite and chew food?

The inability to bite and chew food can be directly linked to deficiencies that affect the health of the gums and teeth, which are crucial for this function. Vitamin C plays a critical role in maintaining healthy connective tissues—including gums—and is essential for the synthesis of collagen. A deficiency in vitamin C can lead to scurvy, characterized by swollen, bleeding gums, and loss of teeth, which severely impacts one's ability to chew.

While vitamin D, calcium, and iron are all important for various aspects of health, they do not specifically impact the structures necessary for biting and chewing to the same extent as vitamin C. Vitamin D is primarily involved in calcium absorption and bone health; calcium is vital for bone and teeth structure; and iron is essential for hemoglobin production and overall energy levels, but none of these directly influence gum health in a way that would lead to difficulties in biting and chewing. Thus, vitamin C is the nutrient most directly connected to this particular issue.