Author: Glossary

Under-carboxylated prothrombin, liberated when vitamin K supplies are suboptimal, which is potentially less functionally efficient than the fully-carboxylated form in supporting normal blood clotting rates; hence the defect in blood clotting that arises in severe vitamin K deficiency. Assay of PIVKA is a more sensitive index in mild vitamin K deficiency than clotting times are,…

Mixture of amino acids and polypeptides prepared by hydrolysis of proteins with acid, alkali or proteases, used in enteral and parenteral nutrition and in supplements. The amino acids obtained from splitting proteins by hydrolysis; used as a source of amino acids in certain diets.  

The protein content of a food or diet expressed as the proportion of the total energy provided by protein (17 kj, 4kcal, / gram). The average requirement for protein is about 7% of total energy intake; average Western diets provide about 14%.  

Aspectrum of disorders, especially in children, due to inad¬ equate feeding. Used to describe children who are wasted or underweight due to insufficient intake of macronutrients. In fact PEM is commonly associated with multiple micronutrient deficiencies. Marasmus is severe wasting and can also occur in adults; it is the result of a food intake inadequate…

Weight gain per weight of protein eaten. The biologic method of estimating protein quality. A measure of the quality of a protein in relation to that of a standard materia1 like casein or skim milk powder. It is determined by growth studies in weaning rats.  

Total nitrogen multiplied by the nitrogen conversion factor = 6.25.  

The thyroid hormones, tri-iodothyronine and thyroxine are transported in the bloodstream bound to proteins; measurement of protein-bound iodine, as opposed to total plasma iodine, was used as an index of thyroid gland activity before more specific methods of measuring the hormones were developed. The binding of almost all thyroxine in the blood to protein. The…

Non-protein part of an enzyme molecule; either a coenzyme or a metal ion. Essential for catalytic activity. The enzyme protein without its prosthetic group is the apoenzyme and is catalytically inactive. With the prosthetic group, it is known as the holo-enzyme. A heat-stable metal ion or an organic group (other than an amino acid) that…

Substances found in plant foods which are precursors of goitrogens.  

Inactive precursors of enzymes, activated after secretion; also called zymogens.