Wednesday, May 25, 2011

L-tyrosine: Building Block for Neurochemicals

Hopefully, you are aware that the DS population has a high incidence of hypothyroidism -- with some sources saying that 100% have, or will develop, thyroid problems in their lifetime. (Learn more at Thyroid & Down Syndrome.) Issues related to the lack of available tyrosine (and/or available iodine) have also been found in those with DS. Since the primary thyroid hormone (T1) is composed of iodine and tyrosine and since some people with DS have difficulties converting phenylalanine into tyrosine, it appears logical that this may contribute to the prevalence of hypothyroidism and that supplemental tyrosine may help. (See more below.)

So, Jett takes 100 mg of l-tyrosine in the morning and afternoon, a half-hour before meals or an hour after meals in order to best metabolize it. Years after Jett had starting taking tyrosine, I had run out. Coincidentally, I got an amino acid panel done on him and it did show that he was low on tyrosine and that I needed to continue supplementation. 

What is Tyrosine?

It's a nonessential amino acid that is synthesized in the body from phenylalanine. As a precursor or building block for several important neurochemicals, tyrosine builds dopamine, epinephrine, and norepinephrine, all of which work to regulate mood. According to the study Disorders of phenylalanine and tyrosine metabolism in Down's syndrome, issues with tyrosine appear to be one of the factors responsible for disturbance of neurotransmitter synthesis and to be related to poor brain function.

Other benefits of tyrosine

Antioxidant Tyrosine is a mild antioxidant as well as having supposed antidepressant effects.

Overcome Depression Tyrosine is the amino acid and inhibitory neurotransmitter that often helps overcome depression. Clinical studies show that tyrosine controls medication-resistant depression.

In a 1980 issue of the American Journal of Psychiatry, a study by Dr. Alan Gelenberg of Harvard Medical School discussed the role of tyrosine in the control of anxiety and depression. Dr. Gelenberg postulated that the lack of available tyrosine results in deficiency of the hormone norepinephrine at a specific location in the brain that relates to mood problems such as depression. Children given tyrosine supplementation demonstrated a marked improvement in mental performance and mood stability.

Reduces Stress (and stress related behavior) Tyrosine, because of its role in assisting the body to cope physiologically with stress and building the bodys natural store of adrenaline, deserves to be called the stress amino acid. Stress exhaustion requires tyrosine. During periods of stress, in order to continue coping with stress physiologically, the brain requires tyrosine. Tyrosine aids children and young teens, as well as adults, with recurrent depression and mood disorders. In children, dosage ranges from 200 to 500 mg daily.
 (See below for more about the adrenals.)

Helps with ADD symptoms (see below).

Reduces DYRK1A levels, which is a contributing factor to mental capacity in those with DS (see below).

Pain Relief Because tyrosine is also involved in the synthesis of enkephalins (opioids), substances that have pain-relieving effects in the body, it appears to have some added pain relief benefits. (Not usually a problem in this population, though.) Tyrosine seems to be especially beneficial when used in conjunction with 5-HTP. (Or l-tryptophan, which Jett used to take but is sufficient in it now.)

Tyrosine & Thyroid

Hypothyroidism is a serious condition that affects glucose metabolism, blood calcium concentration (and therefore ionic balance) and bone density. It can impair growth and cause mental retardation. Iodine deficiency also causes hypothyroidism.

Thyroid hormones are produced from the amino acid Tyrosine (present in commonly consumed food items such as meat, dairy, and eggs) and iodine (found in iodised table salt, kelp, and fish). Functional niacin deficiency (as a result of high tryptophan demands) can result in poor stomach acid that will directly impair digestion of proteins. HCl - stomach acid - activates the enzyme peptidase that is responsible for the main breakdown of proteins. If the stomach produces weak acid, (also a common problem in DS) clearly, protein digestion will be impaired. This means less tyrosine available for the production of thyroid hormones and may result in hypothyroidism.

L-Tyrosine is essential for certain thyroid and adrenal hormones . It is considered to be a non-essential amino acid, which means that if everything is working correctly in the body (which is not always the case with DS), it can convert phenylalanine into tyrosine. However, since it has a synthesis component limited by phenylalanine oxidation, there appears to be more problems producing sufficient quantities of L-tyrosine than other non-essential amino acids. And this is more of a problem in those with DS, probably because the activity of phenylalanine hydroxylase is impaired in the liver of those with DS.

There are apparently other tyrosine issues for those with DS. Even in utero those with DS have a 50% overexpression of the kinase DYRK1A (DYRK1A
is an abbreviation for dual-specificity tyrosine (Y) regulated kinase 1A), which is partially regulated by tyrosine – it may be that this overexpression
of DYRK1A further reduces the available tyrosine for those with DS. DYRK1A is considered to be a candidate for causing the mental retardation and some of the other negative side effects associated with DS. It is possible that consumption of supplemental tyrosine or certain peptides might result in reduced DYRK1A levels (as one such peptide has been successfully tested, [24]), and hence be of benefit to the DS population.

Prefrontal cortex problems (typical ADD like symptoms)
originally from (since been removed) written by MD and neuroscientist, Dr. Daniel Amen

People with PFC (prefrontal cortex problems) seem to have lower availability of the neurotransmitter dopamine. The amino acid L-tyrosine in doses of 500-1500mg two to three times a day for adults and 100-500mg two to three times a day for children under 10 can help. L-tyrosine is the amino acid building block for dopamine. It is reported to increase the level of phenylethylamine (PEA), a mild stimulant that is found in high concentrations in chocolate. Many of my patients have reported that it is helpful for them. It is softer in its effect, but nonetheless they notice a positive effect. Because of absorption patterns I recommend that they take it on an empty stomach (a half-hour before meals or an hour after meals). I have not seen any side effects with L-tyrosine, except for mild weight loss. If there are cingulate problems, l-tyrosine by itself can increase the intensity of overfocused symptoms. Symptoms of tyrosine deficiency include hypothyroidism, low blood pressure, low body temperature (cold hands and feet), and restless leg syndrome. (Jett had all of these symptoms.)
What is the prefrontal cortex?

This area of the brain is thought to be involved in planning complex cognitive behaviours and in the expression of personality and appropriate social behaviour. The prefrontal cortex (PFC) is the very front of the brain, located right beneath the forehead. It is in the anterior (front) region of the frontal lobes. Besides being the front of the brain physically, it is responsible for the executive functions, which include mediating conflicting thoughts, making choices between right and wrong or good and bad, predicting future events, and governing social control — such as suppressing emotional or sexual urges. The prefrontal cortex is the brain center most strongly implicated in qualities like sentience, human general intelligence and personality.


As seen above, in children, dosage ranges from 200 to 500 mg daily or 100-500mg two to three times a day. Jett's doctor recommended he take 100 mg of l-tyrosine in the morning and afternoon, before he eats anything. From an NAET visit Jett showed that, at 3 years old, he still needed it.

For products, see the DS Day to Day amazon store.

If you purchase from vitacost, be sure to get $10 off your first order.


Tyrosine aids in the production of melanin (pigment responsible for hair and skin color). Those with pre-existing pigmented melanoma should avoid tyrosine supplements, as it is suggested that tyrosine may increase the ability of the melanoma cells to spread. It's unusual for people with DS, however, to get cancers other than leukemia.

Before taking any nutritional supplement, including amino acids, please first consult your health care provider.

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