Which substances are classified as nutrients?

• A. Carbohydrates, proteins, fats, vitamins, minerals
• B. Oxygen, carbon dioxide, nitrogen
• C. Water, minerals
• D. Hormones and enzymes

Answer: (A)

Nutrients are substances the body must obtain from the diet to supply energy, support growth and repair, and regulate metabolism. Carbohydrates, proteins, and fats provide energy and are the building blocks for tissues. Vitamins and minerals regulate bodily processes, act as coenzymes, and support enzyme function and structural roles in the body.

The other options mix in substances that aren’t considered nutrients from food in the same way. Oxygen, carbon dioxide, and nitrogen are gases involved in metabolism or respiration, not nutrients obtained from food. Water and minerals are nutrients, but this pairing omits the energy-yielding macronutrients (carbohydrates, proteins, fats) and vitamins, so it isn’t a complete nutrient group. Hormones and enzymes are produced by the body and are not nutrients you digest and absorb as dietary components.

So the set that includes carbohydrates, proteins, fats, vitamins, and minerals best matches what we mean by nutrients.