Phenylalanine and Vitiligo
Phenylalanine is an essential amino acid which is one of the precursors of melanin. Therefore, taking the amino acid can help increase melanin synthesis and repigment the skin. Find out how to take phenylalanine for vitiligo.
by Brad Chase
Phenylalanine is an essential amino acid most noted for being a precursor of tyrosine.
Tyrosine is the used to synthesize neurotransmitters such as dopamine, epinephrine and norepinephrine as well as the skin pigment, melanin.
Although phenylalanine occurs in two chemicals forms (the D- and L- isomers), only L-phenylalanine is obtained from natural sources while D-phenylalanine is produced in the laboratory.
As an amino acid, phenylalanine is obtained from protein-rich foods such as beef, poultry, fish, eggs, milk and milk products.
It is also added to food and drink products. However, these must carry a special label noting its content of the amino acid. This warning label is required because some people cannot metabolize phenylalanine (phenylketonurics).
Another source of phenylalanine is the artificial sweetener called aspartame.
D-phenylalanine is not a building block of any known protein. It is, however, believed to possess some analgesic ability because of its ability to inhibit the enzymes that break down natural pain relievers such as endorphins.
D-phenylalanine is being investigated for treating chronic pain because of its proposed analgesic properties. It is also believed to possess some antidepressant properties.
Sometimes the racemic mixture (DL-phenylalanine) of both forms of phenylalanine is used for treating pain and depression.
Besides chronic pain and depression, phenylalanine is investigated for the treatment of Parkinson’s disease and vitiligo.
Phenylalanine is generally safe to use except by people with phenylketonuria, a rare genetic disorder.
Because it serves as a precursor for important neurotransmitters, low levels of the amino acid or phenylalanine deficiency may cause confusion, depression, lethargy, loss of appetite, inattentiveness and memory disorders.
Recommended doses of phenylalanine should not exceed 5,000 mg per day. A consultation with your physician is necessary before starting phenylalanine supplementation in order to determine whether you have phenylketonuria and rule out any drug interactions.
Reported side effects of DL-phenylalanine are mild. They include heartburn, nausea and headaches.
Vitiligo is a skin pigmentation disorder that is caused by the progressive destruction of melanocytes.
When melanocytes die out, the skin loses its color and turns white. This is because melanocytes are the specialized skin cells responsible for producing melanin, the skin pigment.
Vitiligo affects about 1% of the population and it is usually first diagnosed between the ages of 20 and 40. It affects both sexes equally and it affects people of all races although it is most visible in dark skinned people.
Vitiligo spots usually affects the face, hands and wrists first. It may remain localized or spread.
Body orifices such as the eyes, nostrils, lips, navel and genitals are also common sites for vitiligo spots.
When these spots expand, they change size and shape and then join together to form into white patches all over the skin.
There are different proposed causes of vitiligo and each is supported by clinical evidences. However, the underlying change that causes vitiligo is the death of melanocytes.
The most popular theories regarding the cause of vitiligo are:
This is the most accepted cause of vitiligo and it is backed by the many cases of vitiligo patients who also have other autoimmune diseases.
According to this theory, cells of the immune system including specific antibodies and especially CD8+ T cells are responsible for the destruction of the melanocytes. These immune cells are found in elevated levels in vitiligo patients.
This theory notes that some melanocytes carry intrinsic defects, and therefore, have shorter life spans.
The defect in the melanocytes usually affects their growth. Clinical evidences have shown that melanocytes in vitiligo patients may have malformed cellular structures or lack the right signal receptors.
Harmful free radicals and reactive oxygen species such hydrogen peroxide can damage melanocytes. When the levels of these oxidizing agents rise in the skin, skin cells are placed under oxidative stress.
Usually, there are natural antioxidants (including enzymes, minerals and vitamins) that help mop up these reactive species. However, when the levels of these antioxidants fall, skin cells such as melanocytes are exposed to the destructive effects of the reactive oxidizing species.
Clinical evidences have identified at least 2 oxidized compounds in the skins of vitiligo patients.
These compounds give such skins a yellow-green and bluish glow when examined special light like Wood’s lamp.
Some vitiligo cases have been reported after such patients suffered from nerve damage.
The kind of nerve damage most associated with vitiligo is peripheral nerve damage especially from neurological disorders such as encephalitis.
Such vitiligo is believed to be caused by abnormal and cytotoxic neuropeptides secreted from the damaged nerve endings. These toxic compounds then increasingly destroy melanocytes.
Clearly, vitiligo has a genetic component because 1 in 3 patients have other members of their families with the same hypopigmentation disorder. However, vitiligo is not a simple, directly inheritable disease (only 5 – 7% of children born to vitiligo patients have vitiligo).
However, some variants of certain genes (Apa-I, for example) are associated with increased risk of developing vitiligo.
Melanogenesis is the process by which melanocytes produce melanin.
Melanin is produced in response to DNA damage by ultraviolet radiation. Therefore, melanin protects the skin from further damage.
There are 3 kinds of melanin: eumelanin, pheomelanin and neuromelanin.
Eumelanin and pheomelanin are found in the skin, hair and areola. There are 2 types of eumelanin: black eumelanin and brown eumelanin. Other notable body parts where melanin is found are the choroid of the iris and the inner ear.
Both eumelanin and pheomelanin are produced according to 2 similar pathways. These pathways begin with the conversion of phenylalanine to tyrosine. The enzyme responsible for this reaction is phenylalanine hydroxylase.
Then tyrosine is converted to dopa and then onward to dopaquinone.
Dopaquinone then combines with cysteine to form two intermediates before producing pheomelanin.
Alternatively, dopaquinone can be converted to leucodopachrome, dopachrome and then indole and quinone intermediates before producing eumelanin.
A 1989 study published in the International Journal of Dermatology showed the benefit of oral and topical phenylalanine therapy in the treatment of vitiligo.
In this study, 21 vitiligo patients were recruited and divided into 2 groups. Both groups were given 100 mg/kg of body weight of oral L-phenylalanine combined with UVA exposure for the duration of the study. In addition, one group was also given 10% L-phenylalanine cream to apply on their vitiligo patches.
The results showed that both groups responded well to treatment and no side effects were reported.
However, the better result was obtained in the patients using both oral and topical L-phenylalanine along with UVA exposure.
A 2005 study published in the journal, Molecular Genetics and Metabolism examined the rate of conversion of L-phenylalanine to L-tyrosine in vitiligo patients.
It was found that people with dark skin types have 8 times more enzymatic turnover of L-phenylalanine to L-tyrosine than those with light skin types.
The study also showed that UVB irradiation also increases the activity of phenylalanine hydroxylase for as long as 24 hours after exposure. Therefore, ultraviolet radiation is essential for increasing the conversion of phenylalanine to tyrosine and, thus the formation of melanin.
Lastly, the study showed that the uptake of L-phenylalanine was determined by calcium levels.
Both oral and topical L-phenylalanine can be used in the treatment of vitiligo.
The best way to take oral L-phenylalanine is to take it in a vitiligo supplements containing other vitamins, mineral and/or herbal extracts known to stop the depigmentation of the skin and stimulate its repigmentation.
Callumae is one such vitiligo supplement.
The recommended dose of L-phenylalanine is 50 – 100 mg/kg of body weight. Daily doses should, however, not exceed 3,000 mg.
Since calcium levels determine the uptake of the amino acid, calcium supplementation may be added to L-phenylalanine to speed up the repigmentation of vitiligo patches.
Also UVA and/or UVB exposure should be encouraged to improve results.
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Callumae is a Vitiligo Remedy designed to help get rid of white spots on your skin. Use in conjuction with light therapy (or natural sun light) to help get the most repigmentation to your skin.