What is the primary distinction between fat-soluble and water-soluble vitamins?

The primary distinction between fat-soluble and water-soluble vitamins lies in the body's handling and storage of these nutrients. Water-soluble vitamins, such as the B vitamins and vitamin C, are not stored in significant amounts in the body. As a result, they need to be replenished regularly through the diet to maintain adequate levels, since any excess is typically excreted in urine.

In contrast, fat-soluble vitamins, which include vitamins A, D, E, and K, are absorbed along with dietary fats and can be stored in the body's fatty tissues and liver. This ability to be stored means that the body does not require daily intake of these vitamins, as they can be accessed when needed.

Understanding this distinction is crucial for nutritional planning, as it informs us how to ensure adequate intake of both types of vitamins.