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Protein

A macronutrient made up of amino acids that is essential for the structure and function of cells in the body.

Essential Amino Acids

Amino acids that cannot be produced by the body and must be obtained from food.

Nonessential Amino Acids

Amino acids that can be produced by the body.

Protein Turnover

The continual process of making and breaking down proteins within the body.

Nitrogen Balance

The state in which nitrogen intake from protein equals nitrogen excretion.

Positive Nitrogen Balance

Occurs when the body synthesizes more nitrogen than it degrades, common in growing children and pregnant women.

Negative Nitrogen Balance

Occurs when the body degrades more nitrogen than it synthesizes, often seen in cases of starvation or severe illness.

Proteins

Large biomolecules made up of one or more long chains of amino acid residues.

Dipeptides

Molecules formed by the bonding of two amino acids.

Polypeptides

Long chains of amino acids that form proteins.

High-Quality Proteins

Proteins that provide all essential amino acids in sufficient quantities.

Low-Quality Proteins

Proteins that lack one or more essential amino acids.

Protein-Energy Malnutrition (PEM)

A form of malnutrition that occurs when the diet supplies too little protein.

Kwashiorkor

A severe form of malnutrition characterized by protein deficiency and edema.

Marasmus

A form of malnutrition caused by inadequate intake of protein and calories, leading to severe weight loss.

Antibodies

Proteins that defend the body against pathogens.

Hormones

Chemical messengers in the body; some are proteins.

Amino Acid Composition

The specific arrangement and types of amino acids in a protein, which affects its function.

Complementary Proteins

Two or more protein sources whose amino acids complement each other to provide all essential amino acids.

Protein-Sparing Effect

The preservation of protein intake for growth by ensuring adequate energy intake from carbohydrates and fats.

Protein Quality

The measure of how well a protein source provides all essential amino acids and how easily the protein can be digested.

Recommended Dietary Allowance (RDA) for Protein

The daily allowance of protein recommended for adults, which is 0.8 grams per kilogram of healthy body weight.

Protein Supplements

Products meant to add protein to the diet, typically not necessary for well-fed individuals.