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Medicine LibreTexts

1.1: The Basics of Nutrition

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  • Nutrition can be defined as the science of the action of food, beverages, and their components in biological systems. A nutrient is a compound that provides a needed function in the body. Nutrients can be further classified based on the amount needed in the body.

    • Macronutrients: nutrients needed in larger amounts
    • Micronutrients: nutrients needed in smaller amounts (but still important)

    The following table lists the different macronutrients and micronutrients.

    Table 1.11 Macronutrients and Micronutrients
    Macronutrients Micronutrients
    Carbohydrates Vitamins
    Proteins Minerals


    The name carbohydrate means "hydrated carbon", or carbon with water. Thus, it isn't a surprise that carbohydrates are made up of carbon, hydrogen, and oxygen. Sucrose (table sugar) is an example of a commonly consumed carbohydrate. Some dietary examples of carbohydrates are whole-wheat bread, oatmeal, rice, sugary snacks/drinks, and pasta.

    Figure 1.11 Pancakes, a food source of carbohydrates


    Proteins are also made up of carbon, hydrogen, and oxygen, but they also contain nitrogen. Several dietary sources of proteins include nuts, beans/legumes, skim milk, egg whites, and meat.

    Figure 1.12 Eggs, a food source of protein and lipids


    Lipids consist of fatty acids, triglycerides, phospholipids, and sterols (i.e. cholesterol). Lipids are also composed of carbon, hydrogen, and oxygen. Some dietary sources of lipids include oils, butter, and egg yolks.

    Figure 1.13 Butter, a food source of lipids


    Water is made up of hydrogen and oxygen (H2O) and is the only macronutrient that doesn't provide energy.


    Compounds that are essential for normal physiologic processes in the body.


    Elements (think periodic table) that are essential for normal physiological processes in the body.