Phenylalanine is an essential amino acid found in most foods which contain protein such as meat, fish, lentils, vegetables, and dairy. Phenylalanine is the precursor to another amino acid, tyrosine. Because tyrosine is needed to form several neurotransmitters (dopamine, epinephrine, and norepinephrine), as well as thyroid hormone and melanin, phenylalanine intake is important.
- Adrych K, Smoczynski M, Stojek M, et al. Decreased serum essential and aromatic amino acids in patients with chronic pancreatitis. World J Gastroenterol. 2010;16(35):4422-4427.
- Gropper S SJ, Groff J. Adv Nutr Human Metab. 5th ed. Belmont, CA: Wadsworth, Cengage Learning; 2009.
- Vannucchi H, Moreno FS, Amarante AR, de Oliveira JE, Marchini JS. Plasma amino acid patterns in alcoholic pellagra patients. Alcohol Alcoholism. 1991;26(4):431-436.
- Kim J, Boutin M. A list of phenylalanine to protein ratios for common foods. 2014.
- Stegink LD, Filer LJ, Jr., Bell EF, Ziegler EE. Plasma amino acid concentrations in normal adults administered aspartame
in capsules or solution: lack of bioequivalence. Metabolism: Clin Exp. 1987;36(5):507-512.
- Flydal MI, Martinez A. Phenylalanine hydroxylase: function, structure, and regulation. IUBMB Life. 2013;65(4):341-349.
- Mitchell JJ, Trakadis YJ, Scriver CR. Phenylalanine hydroxylase deficiency. Genet Med. 2011;13(8):697-707.
Low levels of essential amino acids may indicate a poor-quality diet, or maldigestion due to deficient digestive peptidase activity or pancreatic dysfunction. Also, vitamin B3 deficiency has been associated with low levels of several amino acids.
High dietary protein intake may elevate phenylalanine levels. Additionally, some artificial sweeteners contain phenylalanine (NutraSweet® and Equal®); use of these products can result in higher levels. Phenylketonuria (PKU) is a rare genetic mutation of the phenylalanine hydroxylase enzyme which results in high phenylalanine levels. The enzyme requires vitamin C, tetrahydrobiopterin, and iron as cofactors. The mainstay of treatment involves a low-protein diet, cofactor support, and the use of a phenylalanine-free formulas.
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