What vitamin deficiency is associated with swollen gums, mucous bleeding, and poor wound healing?

The symptoms described—swollen gums, mucous bleeding, and poor wound healing—are classically associated with a deficiency of vitamin C, also known as ascorbic acid. Vitamin C is vital for the synthesis of collagen, a key structural protein that helps maintain the integrity of connective tissues, including gums and skin.

In the absence of adequate vitamin C, the body is unable to properly form collagen, leading to weakened connective tissue. This manifests as swollen, inflamed gums that can bleed easily, as well as a tendency for slow wound healing due to impaired skin and tissue repair mechanisms. These clinical features are characteristic of scurvy, the disease resulting from prolonged vitamin C deficiency.

Other vitamins listed do not primarily present with these specific oral and bleeding symptoms. For instance, vitamin A deficiency can lead to issues like night blindness and dry skin, vitamin K deficiency affects clotting factors leading to increased bleeding but does not specifically present with swollen gums, and vitamin B12 deficiency is often associated with anemia and neurological symptoms rather than direct oral manifestations. Thus, vitamin C deficiency is the most accurate answer given the symptoms provided.