Tyrosine

Tyrosine is a non-essential amino acid found naturally in almonds, avocados, bananas, beans, brewer’s yeast, cheese, cottage cheese, dairy products, eggs, fish, lactalbumin, legumes, lima beans, meat, milk, nuts, peanuts, pickled herring, pumpkin seeds, seafood, seeds, sesame seeds, soy, whey, and whole grains.

Tyrosine is a precursor for the neurotransmitters L-dopa, dopamine, norepinephrine, and epinephrine. Due to its effect on neurotransmitters, it is thought that tyrosine may benefit people with Parkinson’s disease, dementia, depression, and other mood disorders. A study of US marines found that the amino acid helps to increase alertness in people suffering from sleep deprivation. Skin cells use tyrosine to form melanin, the pigment that protects against the skin from the damaging effects of ultraviolet light. Thyroid hormones, which play many important roles throughout the body, also contain tyrosine as part of their structure. In fact, tyrosine is used to produce the hormone thyroxin, which is important in the regulation of growth and metabolism, and is required for healthy skin and the maintenance of mental health. Finally, tyrosine may be of benefit to people who suffer from PKU.

Signs and symptoms of tyrosine deficiency include: apathy, blood sugar imbalances, depression, edema, fat loss, fatigue, lethargy, liver damage, loss of pigmentation in hair, low serum levels of essential blood proteins, mood disorders, muscle loss, skin lesions, slowed growth in children, and weakness.

The therapeutic dosage of tyrosine is 7 to 30 g daily, depending upon requirements.

A maximum safe level for tyrosine has not been established. Furthermore, it is not known whether long-term, high-dosage (i.e. doses in excess of 1,000mg a day) use of Ltyrosine is safe. For this reason, long-term use of tyrosine at any dosage should be monitored by a doctor.

Supplementary tyrosine can cause hypertension, hypotension, and migraine headaches in susceptible individuals. People who are allergic to eggs, milk, and wheat, and those who suffer from migraine headaches, phenylketonuria (PKU), melanoma, and hypertension should not take tyrosine. If taken in combination with monoamine oxidase inhibitor (MAOI) antidepressants, for example isocarboxazid, phenelzine, and procarbazine, tyrosine can cause potentially dangerous hypertension. People with kidney disease or liver disease should consult their doctor before taking tyrosine.