What type of vitamins includes A, D, E, and K?

The correct answer is fat-soluble vitamins, which include vitamins A, D, E, and K. These vitamins are characterized by their solubility in lipids (fats), which allows them to be stored in the body's fatty tissues and in the liver. This storage capability means that these vitamins do not need to be consumed as frequently as water-soluble vitamins, which are excreted more readily in urine.

Fat-soluble vitamins play critical roles in various bodily functions; for example, vitamin A is essential for vision and immune function, vitamin D is important for calcium absorption and bone health, vitamin E acts as an antioxidant, and vitamin K is crucial for blood clotting. Understanding the nature of these vitamins helps in recognizing the dietary sources necessary to maintain optimal health.