Phenylalanine

phenylalaninePhenylalanine is an essential amino acid, meaning that it is necessary for human health but is not produced by the body. As L-phenylalanine (LPA), it is one of the twenty common amino acids. In 1959, Marshall Warren Nirenberg discovered the genetic codon for phenylalanine.

Sources

Since it is not produced by the human body, phenylalanine is obtained through the diet. Some foods rich in phenylalanine include:

Asparagus
Beef
Cottage cheese
Chicken
Chickpeas (garbanzo beans)
Cowpeas (raw)
Egg (yolk, white or whole)
Fish
Flax seed
Hummus
Lentils (dry and whole)
Meats
Milk (sheep, goat, mother’s milk)
Pork
Poultry
Peanuts (roasted with skins)
Salmon
Seafood
Sesame seeds
Shrimp
Soybeans (raw)
Soy milk
Walnuts

Phenylalanine may also be obtained through supplements.

Deficiency

A phenylalanine deficiency may occur when sufficient amounts are not given to the body. Some symptoms may include:

  • Apathy
  • Confusion
  • Decreased alertness
  • Lack of energy
  • Loss of muscle
  • Lowered appetite
  • Memory troubles
  • Stunted growth
  • Weakness

Benefits

L-phenylalanine is the natural form of phenylalanine. Along with UVA radiation, it has shown a return of pigment to white areas in patients with vitiligo.

D-phenylalanine is a synthesized form. It is thought to stimulate nerve pathways, therefore assisting in the reduction of chronic pain in some medical conditions. It is also thought to assist in walking and speech difficulties, and depression found in Parkinson’s disease.

DL-phenylalanine is a combined form of both D and L. It is claimed to have pain-killing and anti-depressant benefits.

Phenylketonuria

Phenylketonuria, also known as PKU, is a genetic disorder regarding an individual’s inability to properly metabolize phenylalanine. Persons with phenylketonuria (phenylketonurics) need to avoid phenylalanine intake, including aspartame, a well-known artificial sweetener.