Which vitamin is primarily associated with blood clotting?

Vitamin K is primarily associated with blood clotting due to its crucial role in the synthesis of certain proteins that mediate the coagulation process. These proteins, known as clotting factors, are essential for the formation of blood clots that prevent excessive bleeding when injuries occur. Vitamin K exists in two main forms: K1 (phylloquinone) found in leafy greens and K2 (menaquinone) produced by gut bacteria. Deficiency in vitamin K can lead to increased bleeding tendencies and can exacerbate conditions related to blood coagulation disorders.

In contrast, vitamin A is primarily involved in vision, immune function, and skin health. Vitamin D is essential for calcium absorption and bone health and does not play a direct role in blood clotting. Vitamin B12 is critical for nerve function and the production of DNA and red blood cells, rather than for the mechanisms of coagulation. Thus, vitamin K is the key nutrient directly associated with the complex physiological process of blood clotting.