Phenylalanine is an amino acid and is considered the main precursor of various catecholamines such as dopamine, adrenaline and noradrenaline. In addition, phenylalanine is converted in the brain to phenylethylamine, a naturally occurring neurotransmitter that helps to maintain a normal mood.
The essential amino acid phenylalanine itself is active in the protein formation of certain neurotransmitters in the brain. The positive effects on mood, the nervous system in general and on well-being depend on sufficient intake through food. Phenylalanine is also said to help reduce symptoms such as irritability and fatigue. Phenylalanine can also be metabolised in the body to tyrosine.
Phenylalanine is found in most foods with a high protein content. Foods made from soy are particularly rich in this substance, but so are beef, lentils, cashews and oatmeal. However, a deficiency of phenylalanine is rarely observed in civilised countries, e.g. in cases where a person eats a low-protein diet for a long period of time.
If the absorption of phenylalanine through the diet is not sufficient or there is an increased need, this nutrient can be supplemented through special food supplements.