L-Tyrosine is a nonessential amino acid the body makes from another amino acid called phenylalanine.
Phenylalanine is the starting compound used in flavonoid biosynthesis. Lignan is derived from phenylalanine and from tyrosine.It is an essential component for the production of several important brain chemicals called neurotransmitters, including epinephrine, norepinephrine, and dopamine.
Neurotransmitters help nerve cells communicate and influence mood. Tyrosine also helps produce melanin, the pigment responsible for hair and skin color. It helps in the function of organs responsible for making and regulating hormones, including the adrenal, thyroid, and pituitary glands.
It is involved in the structure of almost every protein in the body. It's rare to be deficient in tyrosine. Low levels have been associated with low blood pressure, low body temperature, and an underactive thyroid. This does not mean, however, that taking tyrosine supplements will help any of these conditions.
Phenylketonuria (PKU) This is an inborn error of metabolism involving impaired metabolism of phenylalanine. Phenylketonuria is caused by absent or extremely low phenylalanine hydroxylase (PAH) enzyme activity.
The role of PAH is to break down excess phenylalanine from food. Phenylalanine is a necessary part of the human diet and is naturally present in all kinds of dietary protein. It is also used to make the sweetener aspartame, known by the trade name Nutrasweet. The enzyme PAH breaks down excess phenylalanine from these sources beyond what is needed by the body.
However, if there is not enough of the PAH enzyme or its cofactor, then phenylalanine can build up in the blood and brain to toxic levels, affecting brain development and function. This can lead to brain damage and intellectual impairment. PKU is rare, but important to identify, because if caught early it is very treatable. It is not contagious but it is lifelong With early diagnosis and consistent treatment, the damaging effects can be minimal or non-existent.
Protein-rich foods or the sweetener aspartame can act as poisons for people with phenylketonuria.
Tyrosine is used in protein supplements for people with PKU, but most doctors don't recommend tyrosine supplements. If you have PKU, your doctor will determine if you need more tyrosine and how much.
Stress
Tyrosine is involved in the production of the stress neurotransmitters epinephrine and norepinephrine. Some researchers believe that, under stress, the body isn't able to make enough tyrosine from phenylalanine. Some animal and human studies suggest that tyrosine supplements may help improve memory and performance under psychological stress. More research is needed.
Sleep deprivation
One study suggests that taking tyrosine may help you be more alert after sleep deprivation.
More research is needed.
Some athletes claim that tyrosine helps their performance. However, there is no proof that this claim is true or safe.
Preliminary research suggests that tyrosine kinase inhibitors may play a role in the treatment of thyroid cancer. Other studies suggest tyrosine kinase inhibitors may help improve lung function among people who have lung cancer or pulminary fibrosis.
Mental health
L-tyrosine appears to have particular benefits for mental health and mental performance, many people choose to take supplements of this amino acid or eat more food containing it, such as meat, seafood, dairy products and whole grains.
Because tyrosine helps the body produce the mood-influencing chemical dopamine, and because people who are depressed often have low levels of tyrosine, researchers thought that tyrosine might help treat depression. Studies have found that it has no effect.
Dietary Sources
Tyrosine is found in soy products, chicken, turkey, fish, peanuts, almonds, avocados, bananas, milk, cheese, yogurt, cottage cheese, lima beans, pumpkin seeds, and sesame seeds. Amino acids are building blocks of protein. L-tyrosine is a non-essential amino acid, meaning you don't need to obtain it from diet as long as you consume enough L-phenylalanine, which the body converts to tyrosine.
Consult a qualified health care provider before taking acetyl-L-tyrosine supplements.
Absorption
Acetyl-L-tyrosine is a type of L-tyrosine supplement that the body converts to tyrosine. It is more rapidly absorbed and has better bioavailability than L-tyrosine supplements, so less of it is lost through urine. In addition, you can take a smaller dose of acetyl-L-tyrosine to obtain the same effects of a larger dose of L-tyrosine.
This is beneficial, because large doses of L-tyrosine can cause irritability, restlessness, anxiety and abnormal heart rhythms, according to physician Ray Sahelian, who specializes in natural supplements. Tyrosine is also available as a dietary supplement, in capsule or tablet form. Take tyrosine supplements at least 30 minutes before meals, divided into 3 daily doses. Taking vitamins B6, B9 (folate), and copper along with tyrosine helps the body convert tyrosine into important brain chemicals. To treat symptoms of sleep deprivation, one study used 150 mg per kilogram of body weight per day
References:University of Maryland Medical Center, DrGreene.com
