Conditionally essential amino acids

Conditionally essential amino acids such as taurine, aspartic acid, and glutamic acid are available in some commercially available CAA solutions. 

Other conditionally essential amino acids, such as cysteine, carnitine, and glutamine, are not included because they are unstable or insoluble. Cysteine and carnitine are commonly added to PN solutions compounded for newborns. 

Finally, they may be classified on the basis of whether they are nonessential, essential (exogenous), and conditionally essential amino acids. Food and tissue proteins contain 20 amino acids of nutritional importance. Nine of these amino acids (histidine (His), He, Leu, Lys, methionine (Met), Phe, Thr, Trp, and Val) cannot be synthesized by the body and they are therefore essential or indispensable nutrients that must be... 

Cysteine Cysteine is a conditionally essential amino acid but is not included in commercial feeds because it is not stable in such solutions. It is, however, provided as IV-acetylcysteine, which is slowly hydrolysed in vivo to release cysteine ... 

They are required for the synthesis of conditionally essential amino acids, e.g. arginine, glycine, cysteine and glutamine. 

The diversity of size and form of babies bom even after normal pregnancy is remarkable. However, this is not only due to genetic variation but to the behaviour and nutrition of the mother adequate nutrition, macro- plus micronutrients, plus the essential fatty acids, essential amino acids and the conditionally essential amino acids. Too high an intake of alcohol and smoking tobacco are known to affect the size of the baby with, in some cases, a reduction in the nnmber of cells in particular tissues/organs. 

It should be noted that there is a growing list of conditionally essential amino acids. These are amino acids that must be augmented through the diet under a variety of special circumstances. Often these circumstances include infancy (where the various enzyme systems for metabolism have not been fully expressed) or periods of metabolic stress due to injury or illness. Conditionally essential amino acids include taurine (infants) and glutamine (metabolic stress). 

JM Lacey, DW Wilmore. Is glutamine a conditionally essential amino acid Nutr Rev 48 297-309, 1990. 

The eight essential amino acids are not synthesized in the body and have to be supplied in the diet. The conditionally essential amino acids, although synthesized in the body, may require supplementation during certain physiological conditions such as pregnancy. The non-essential amino acids can be synthesized from various metabolites. 

Several commercially available CAA solutions are designed to provide conditionally essential amino acids (CEAAs). CEAAs are considered nonessential during health because they are produced from other amino acids. However, under certain physiologic conditions such as prematurity or sepsis, these amino acids cannot be synthesized in sufficient quantities. CAA solutions specifically designed for use in neonates and pediatric patients contain increased amounts of taurine, aspartic acid, and glutamic acid. Other CEAAs, such as cysteine, carnitine, and glutamine, are not available in commercial CAA solutions in pharmacologic amounts because they are relatively unstable or poorly soluble. ... 

CAA crystalline amino acid CEAA conditionally essential amino acid CPN central parenteral nutrition CSP compounded sterile preparations EFAD essential fatty acid deficiency... 

Lourengo, R. and Camilo, M. E. (2002). Taurine A conditionally essential amino acid in humans An overview in health and disease. Nutr. Hasp. 17, 262-270. 

An essential amino acid cannot be synthesized in the humans and must, therefore, be supplied in the diet. Conditionally, essential amino acids are not normally required in the diet, but must be supplied exogenously to specific populations that do not synthesize them in adequate amounts. 

Phenylketonuria (PKU) is an inborn error in phenylalanine metabolism caused by a deficiency of the phenylalanine hydroxylase (PAH) enzyme (Fig. 10.1). The cofactor for PAH is tetrahydrobi-opterin (BH4). In PKU, blood concentrations of phenylalanine accumulate, affecting myelin and neurotransmitter production (Box 10.1) [1,2], With the defect in PAH, phenylalatfine is not converted to tyrosine thus, tyrosine becomes a conditionally essential amino acid and must be... 

Tyrosine is a conditionally essential amino acid in the MPKU diet. Medical food is the major source of dietary tyrosine therefore if a woman has low blood tyrosine, check to make sure she is taking all of her medical food. Blood tyrosine fluctuates diumally and is lowest after an overnight fast. Before adding a tyrosine supplement, monitor non-fasting blood tyrosine concentrations to assess whether supplementation is necessary [15]. 

Sinha, M., Manna, R, Sil, P.C., 2007. Taurine, a conditionally essential amino acid, ameliorates arsenic-induced cytotoxicity in murine hepatocytes. Toxicol In Vitro 21,1419-1428. 

Different fonts indicate nonessential amino acids, essential amino acids, and conditionally essential amino acids. 

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