Phenylalanine is an essential amino acid that is also one of the most commonly found aromatic amino acids. It is contained in most protein-rich foods but good sources are dairy products, almonds, avocados, lima beans, peanuts and seeds.
Phenylalanine exhibits ultraviolet radiation absorption properties. It can be converted in the body to tyrosine, which in turn is used to synthesize two important neurotransmitters - dopamine and norepinephrine.
Phenylalanine is available in three different forms; L-, D- and DL-. The L- form is the most common and is the type which is incorporated into the body's proteins. The D- form acts as a painkiller and the DL- is a combination of the two.
It is used in elevating the mood since it is so closely involved with the nervous system, as well as helping with memory and learning, as an appetite suppressant and to increase sexual interest.
It is also used to treat depression, and the D- form may also be helpful in the treatment of Parkinson's disease and chronic pain in both osteo-arthritis and rheumatoid arthritis. It also increases blood levels of norepinephrine, epinephrine and dopamine – which are all required for neurotransmission.
Dietary deficiency is rare, but symptoms may include lethargy, weakness and skin lesions, as well as liver damage and slow growth. A deficiency in diet would only occur with an extremely low protein intake.
This nutrient is thought to be of great benefit to those suffering from Parkinson's disease, tiredness, depression, alcohol withdrawal, rheumatoid arthritis, osteo-arthritis and vitiligo.