PROP Nutrition Management Guidelines
First Edition
March 2017, v.1.2
Updated: September 2017
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Appendix B: Terms
Important Terms Used in This Document

Appendix B

Terminology of Proteins and Related Nutrients



Intact protein

A protein containing amino acids attached through amide (peptide) bonds; also described as food protein or natural protein

Incomplete protein

A protein containing insufficient amounts/ratios of one or more essential amino acids to support optimal growth and maintenance when used as a sole protein source. Incomplete proteins may be combined to complement each other in a mixed diet. Incomplete proteins may be described as being of “low biological value”

Complete protein

A protein containing sufficient amounts/ratios of the essential amino acids to support growth and maintenance when used as the sole protein source. Complete amino acid mixtures that are used for parenteral feedings may also be referred to as complete proteins. Complete proteins may be described as being of “high biological value”

Medical food

“Food which is formulated to be consumed or administered enterally under the supervision of a physician and which is intended for the specific dietary management of a disease or condition for which distinctive nutritional requirements, based on recognized scientific principles, are established by medical evaluation.”1 An example would be a medical food specific for the amino acidopathy, phenylketonuria (PKU), that eliminates the amino acid phenylalanine and adds supplemental tyrosine

Amino acid supplement

Single amino acids added in varying amounts to establish appropriate blood/tissue concentrations. An example would be the addition of LEU and/or VAL to correct plasma amino acid concentrations in an individual with MSUD who is using a BCAA-restricted medical food

Low protein modified food/product

“A type of medical food that is modified to be low in protein and formulated for oral consumption for individuals for whom a condition or disorder prevents typical food consumption. This does not include foods that are naturally low in protein, such as some fruits or vegetables.” 2  Examples are baked goods or pastas that are prepared with wheat starch rather than wheat flour to minimize the contribution of gluten to the total protein content

Natural low protein food

Naturally occurring foods that contain little or no protein. Examples include oils and sugars. Some fruits and a few vegetables have a very low protein content

Protein equivalent

A means of comparing the nitrogen content of a given amount of a food source to that found in the same amount of a complete protein. Often this is used to compare amino acid- based medical foods to formulas with intact protein. Intact proteins contain a higher percentage of nitrogen per gram than amino acids because one molecule of water is lost during the formation of each peptide/amide bond when amino acids combine to form a protein

1 defined in section 5(b) of the Orphan Drug Act (21 U.S.C. 360ee (b) (3))

2 from the Food and Drug Administration, food and dietary supplement statutes