Which deficiency is most closely linked to problems with blood clotting?

• A. Vitamin K deficiency
• B. Vitamin E deficiency
• C. Vitamin C deficiency
• D. Vitamin A deficiency

Answer: (A)

Blood clotting depends on several clotting factors that must be activated to form a proper clot. Vitamin K is essential because it enables the liver to activate these factors (including II, VII, IX, and X) through a chemical modification called gamma-carboxylation. When vitamin K is deficient, these factors can’t be activated correctly, so the clotting process is slowed or impaired, leading to prolonged bleeding and easy bruising.

The other vitamins listed don’t primarily govern the clotting cascade. Vitamin E is mainly involved in protecting cells from oxidative damage and isn’t a key driver of coagulation. Vitamin C deficiency affects collagen and connective tissues, resulting in symptoms like gum disease and poor wound healing, not impaired clotting. Vitamin A deficiency impacts vision and immune function rather than the clotting system. That’s why vitamin K deficiency is the best fit for problems with blood clotting.