ISSA Nutritionist Practice Exam

How are most vitamins classified?

1. Minerals and trace elements

2. Fat-soluble and water-soluble

3. Synthetic and organic

4. Lipid and carbohydrate soluble

The correct answer is: Fat-soluble and water-soluble

Vitamins are primarily classified based on their solubility properties, which defines how they are absorbed, transported, and stored in the body. The classification into fat-soluble and water-soluble vitamins is crucial for understanding their functions and dietary sources. Fat-soluble vitamins, including vitamins A, D, E, and K, dissolve in fats and oils and can be stored in the body's fatty tissues and liver. This means they do not need to be consumed as frequently as water-soluble vitamins, as they can accumulate in the body. On the other hand, water-soluble vitamins, such as the B-complex vitamins and vitamin C, dissolve in water and are typically not stored in the body to a significant extent. They need to be replenished regularly through diet because any excess amounts are generally excreted in urine. The other classifications provided do not accurately represent how vitamins are commonly categorized. For instance, the distinction between minerals and trace elements does not pertain to vitamins, and synthetic versus organic refers more to the origin of compounds rather than their classification as vitamins. Similarly, lipid and carbohydrate soluble is not a recognized classification for vitamins, as it does not encompass the two main categories of vitamins.