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Nutrition
Article by: Donald R. Davis, College of Natural Sciences, Clayton Foundation Biochemical Institute. University of Texas, Austin, Texas.
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The science of nourishment, including the study of the
nutrients that each organism must obtain from its environ-
ment to maintain life and health and to reproduce. Nutri-
tion is essential for survival. Organisms nourish themselves by
assimilating the nutrients from their surroundings and from the
foods that they consume (Fig. 1), and then using those nutrients
to meet their requirements for energetic activity, metabolism,
growth, and tissue repair and replacement. Although each
kind of organism has distinctive nutrition needs, the underly-
ing biochemical unity in nature gives coherence to the subject.
Many nutrients, including amino acids, minerals, and vitamins,
required by higher organisms may also be needed by the sim-
plest forms of life, including single-celled bacteria and protozoa.
Recognition of this fact has made possible highly important
developments in biochemistry.
Nutrition in Humans and Other Mammals
In addition to water and oxygen, mammals need a highly
complex mixture of more than 40 chemical substances for their
nutrition. These include amino acids; carbohydrates; certain lip-
ids; fibers (for preventing constipation and diverticular disease
and for slowing the absorption of carbohydrates); a great vari-
ety of minerals, including several so-called trace minerals that
are required only in minute amounts; and vitamins (organic
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Key Concepts
• To survive and reproduce, every living organism needs to consume nutrients from its environment.
• Every organism has unique nutritional needs. However, nutrients such as amino acids, minerals, and vitamins,
may be needed by all forms of life.
• Humans and other mammals need more than 40 chemical substances for their nutrition, including lipids and fibers,
in addition to amino acids, minerals, and vitamins.
• Most requisite nutrients can be obtained from whole foods; that is, foods that have not undergone
substantial processing.
• Individuals have differing nutritional needs, which makes it difficult to state with certainty the amounts of specific
nutrients that are needed for good health.
Fig. 1: Nutrition is key for a healthy life. Many government agencies provide information and
guidelines about the nutritional requirements for a proper human diet.
(Credit: United States Department of Agriculture)
