Nutrition

Nutrition is the science of food, the nutrients and other substances it contains, and its actions within the body (including ingestion, digestion, absorption, transport, metabolism, and excretion).

Humans primarily eat food to nourish their bodies. This food contains nutrients for the maintenance of life and the growth and repair of tissue such as skeletal muscle.

Figure 1. Different foods contains different levels of nutrients.

Macronutrients are nutrients that the body needs in relatively large amounts (many grams daily). Nutrients that we consider macronutrients are carbohydrate, protein, and fat.

Micronutrients are nutrients that the body needs in relatively small amount (milligrams or micrograms daily). Nutrients that we consider micronutrients are vitamins and minerals.

Micronutrients are used to build and repair tissues and to regulate body processes, while macronutrients are converted to and used for energy.

Essential nutrients are nutrients that a person must obtain from food because the body cannot make them by itself in sufficient quantities.

References:

• Rolfes,S. Understanding normal and clinical nutrition 8th ed. Wadsworth, Cengage Learning,