Which vitamin is known for causing swelling in the gums when deficient?

The correct answer is Vitamin C. A deficiency in Vitamin C can lead to scurvy, which is characterized by various symptoms, including swelling and bleeding of the gums. This happens because Vitamin C plays a critical role in collagen synthesis, which is essential for maintaining the integrity of connective tissues, including those in the gums. Without sufficient Vitamin C, gum health deteriorates, leading to inflammation and swelling.

Vitamin A is primarily involved in vision and immune function, while Vitamin B2 (Riboflavin) is more closely associated with energy production and cellular function, without a direct correlation to gum swelling. Vitamin D is primarily involved in calcium absorption and bone health, and while it impacts oral health indirectly, it does not specifically cause gum swelling when deficient.