Here's why:

* Organic compounds are molecules that contain carbon atoms bonded to other atoms, primarily hydrogen, oxygen, nitrogen, and sometimes phosphorus and sulfur.

* Inorganic compounds lack carbon-hydrogen bonds.

Therefore, any nutrient containing carbon as a key structural component is classified as organic. Examples of organic nutrients include:

* Carbohydrates: sugars, starches, and fibers

* Lipids (fats and oils): triglycerides, phospholipids, sterols

* Proteins: amino acids, peptides, polypeptides

* Vitamins: Vitamin A, Vitamin C, Vitamin D, etc.

In contrast, inorganic nutrients include:

* Minerals: calcium, iron, sodium, potassium, etc.

* Water: H2O

Note: The term "organic" in this context refers to the chemical structure of a molecule and is different from the term "organic" used in agriculture and food labeling, which refers to how food is grown or produced.