Causes Of L-Phenylalanine Deficiency: Symptoms And Functions

Phenylalanine is one of the nine essential amino acids. Amino acids are very important building blocks for protein. L phenylalanine is one form of phenylalanine available naturally in foods. Just like other essential amino acids phenylalanine in not prepared in the body. It is obtained by eating foods such as almonds, meat, beans and legumes, dairy products etc.

It is very important to eat sufficient amount of food containing phenylalanine for maintaining normal composition of protein in the body. Phenylalanine plays an important role in production of certain brain chemicals that have direct implications on your mood.

Deficiency of phenylalanine can cause confusion, memory problems, depression, altered alertness etc.

Functions Of Phenylalanine In The Body

Phenylalanine has three different forms.

  • L Phenylalanine which is present in foods in its natural form.
  • D- Phenylalanine is prepared artificially in laboratory.
  • DL- Phenylalanine is combined form of the above two.

Once L phenylalanine is inside the body, it gets converted into another amino acid called tyrosine. Tyrosine is needed to produce protein as well as neurotransmitters L-dopa, norepinephrine, epinephrine and thyroid hormones which have different roles such as controlling metabolism and mood.

It also controls the secretion of cholecystokinin which gives signal to the brain the feeling of satisfaction once you eat the food.

Phenylalanine is also essential for production of skin pigment melanin.

Good food sources of L- phenylalanine: L phenylalanine is present in almost all protein rich foods. It is found naturally in breast milk thus even infant is able to get it from mother’s milk. The top source of L phenylalanine is fish, poultry, beef meat, pork, lamb meat, seafood, cottage cheese, peanuts roasted, sesame seeds, soybeans, tofu, soymilk, almonds and milk,

Symptoms Of Phenylalanine Deficiency

Since phenylalanine has its influence on brain function, patients suffering from phenylalanine deficiency are often confused. They have altered alertness and weak memory. Due to sluggish metabolism as a consequence of low thyroid output patient may always feel lack of energy and tired. Patient has constant feeling of depression as the hormone that influences mood is produced less due to deficiency of phenylalanine.

Patient who is markedly deficient in phenylalanine may suffer from skin condition called vitiligo. It is a condition in which the melanocyte cell of skin does not produce melanin a pigment which gives color to the skin. Hence patients may develop white patches on the skin. Studies have suggested that use of L- phenylalanine together with UV light have lead to darkening of the white skin patches.

Causes Of L-Phenylalanine Deficiency

The body may not be able to receive L- phenylalanine as it is needed in certain amount under two circumstances. The person does not eat foods that has rich source of L- phenylalanine. It may occur in people who have poor intake of protein containing food. Certain factors may be the triggers such as starvation, staying in areas which have been affected with draught and famine where there is lack of food provision.

Phenylketonuria is a genetic disorder which occurs in newborn. It is a rare disease in which an enzyme called phenylalanine hydrozylase is missing. This enzyme is needed to metabolize L phenylalanine that is present in food to tyrosine. Since breakdown of phenylalanine does not occur, it gets collected in the blood to very high level which may cause irreversible damage to the infant’s brain.

It may cause permanent damage to the brain leading to mental retardation if genetic disorder is not detected in three weeks after birth of child. Thus in many countries newborn babies are tested for phenylketonuria within 3 days after birth. People suffering from phenylketonuria have to restrict eating foods containing phenylalanine. They have to take supplementary tyrosine.