L-Phenylalanine

L-phenylalanine is also known as beta-phenylalanine, (S)-2-amino-3- phenylpropanoic acid, alpha-aminohydrocinnamic acid and alpha-amino-beta-phenylpropionic acid. It is abbreviated as either Phe or by its one-letter abbreviation F. The molecular formula of L-phenylalanine is C9H11NO2, and its molecular weight is 165.19 daltons. L-phenylalanine is the precursor of L-tyrosine via the enzyme L-phenylalanine hydroxylase. It is this enzyme that is absent in those with the genetic error of metabolism called phenylketonuria (PKU). Aspartame is a dipeptide of L-phenylalanine; however, this form is related to numerous side effects.

Function- Phenylalanine is available in three different forms referred to as L-, D-, and DL-. The L- form is the most common type (of any nutrient because it is the most absorbable) and is the form in which phenylalanine is utilized into the body's proteins. The D- type acts as a painkiller. The DL- form is a combination of the D- and the L- form. Like the D-form, it is effective for controlling pain, such as the pain of arthritis; and it functions as a building block for proteins, elevates mental alertness, acts as an appetite suppressant, and has been useful with Parkinson's disease. It has also been used to alleviate the symptoms of premenstrual syndrome (PMS) and various types of chronic pain.

Pain- Research has shown that many who suffer from chronic pain commonly have reduced levels of endorphins and enkephalins in the cerebral spinal fluid and serum plasma levels. It appears from research that DL-Phenylalanine inhibits enzymes that are responsible for the break down of endorphins and enkephalins. Endorphins and enkephalins act as mild mood elevators and are potent analgesics, that is, substances that alleviate pain. Studies suggest DL- Phenylalanine is effective against the chronic pain of osteoarthritis, rheumatoid arthritis, low back pain, migraines, PMS, whiplash and joint pains. Phenylalanine appears to allow the pain relieving attributes of endorphins a longer time span for their pain relieving action. The Phenylalanine is not acting as an analgesic, but instead is allowing the natural pain control mechanism of the body to act in a more advantageous manner.

Depression- Phenylalanine has commonly been found to be deficient in patients diagnosed with depression. Phenylalanine is highly concentrated in the human brain and plasma. Research shows that phenylalanine crosses the blood brain barrier faster than any other amino acid and is found in significant amounts in brain protein being equally distributed throughout the white and gray matter. Phenylalanine supplies the raw materials for the neuropeptides vasopressin, melatonin, substance P, adrenocorticotrophin (ACTH), somatostatin, angiotensin II, enkephalins, vasoactive intestinal peptide, and cholesystokinin. Phenylalanine is converted into the neurotransmitters norepinephrine, epinephrine and dopamine.

Premenstrual syndrome- Phenylalanine is commonly used to alleviate emotional and physiological symptoms occurring with PMS.

Stress- The best known of these phenylalanine producing neurotransmitters is the hormone adrenalin. Adrenalin is produced by the adrenal glands and allows us to cope with stress. Stress uses up an incredible amount of nutrients by the body and the amino acid phenylalanine (also tyrosine) are necessary for the production of the catecholamines such as adrenalin. Because phenylalanine (especially in combination with tyrosine) improves your body's production of adrenalin, it may be inadvisable to take them if you suffer from high blood pressure and low blood pressure. This is because the adrenal glands have a major impact on vaso-dilation and vaso-constriction of arterioles.

Weight control- Phenylalanine has been shown to stimulate the thyroid gland, increasing the rate of metabolism and thus helping the body to mobilize fat deposits and use food more efficiently. These changes help the patient to lose weight. Another of phenylalanine's actions is to stimulate the intestines to produce a hormone called cholesystokinin (CCK) which tells the brain when you have eaten enough and acts as an appetite suppressant. This is a benefit to any weight loss program.

Deficiency- Because of its relationship with the central nervous system, this amino acid can elevate mood, decrease pain, aid in memory and learning, and suppress the appetite. It can be used to treat arthritis, depression, menstrual cramps, migraines, obesity, Parkinson's disease, and schizophrenia.

Sources- Food sources which contain phenylalanine include soybeans, cottage cheese, fish, meat, poultry, cheese, corn, eggs, almonds, brazil nuts, pecans, pumpkin seeds, sesame seeds, lima beans, chickpeas (garbanzos), lentils, brown rice and yogurt.

Precautions- Supplemental phenylalanine should NOT be taken by people who suffer from phenylketonuria (PKU) and pregnant women should check with their physician.

Requirements- There is no Recommended Dietary Allowances (RDA) listed. Individual needs may differ due to clinical conditions, biochemical individuality and absorption. All sources of nutrients should be consumed in their most natural state, in the form of a variety of foods or supplements when necessary. Free form amino acid supplements are immediately absorbed by the body and should be consumed with natural occurring cofactors for best results. Consulting with a physician that is properly trained in the natural healing sciences and amino acid therapy may be needed for optimum results.

Written by Jerome Rerucha D.C.

References-
1. Camacho F, Mazuecos J. Treatment of vitiligo with oral and topical phenylalanine: 6 years of experience. Arch Dematol. 1999; 135:216-217.
2. Kostiuk PG, Martyniuk AE. [Possible molecular mechanisms of brain dysfunction in phenylketonuria.] [Article in Russian.] Patol Fiziol Eksp Ter. 1992; Jul-Aug(4):34-36.
3. Sabelli HC, Fawcett J, Gusovsky F, et al. Clinical studies on (he phenylalanine hypothesis of affective disorder: urine and blood phenylacetic acid and phenylalanine dietary supplements. J din Psychiatry. 1986; 47:66-70.
4. Siddiqui AH, Stolk LM, Bhaggoe R, et al. L-phenylalanine and UVA irradiation in the treatment of vitiligo. Dermatology. 1994; 188:215-218.
5. Gardos G, Cole JO, Matthews JD, et al. The acute effects of a loading dose of phenylalanine in unipolar depressed patients with and without tardive dyskinesia. Neuropsychopharmacology.
1992: 6:241-247.
6. Bland, J., (editor), Medical Applications of Clinical Nutrition, Keats, 1983.
7. Nutrition Almanac, McGraw Hill, 1979.
8. American J. of Psychiatry 147:622, May 1980.
9. Pearson D., and Shaw,S., Life Extension, Warner Books, 1984.
10. Avraham, Y., Hao, S., Mendelson, S., Berry, E.M. Tyrosine improves appetite, cognition, and exercise tolerance in activity anorexia. Med. Sci. Sports Exerc. 2001 Dec; 33(12): 2104-10.
11. Leyton, M., Young, S.N., Pihl, R.O. A comparison of the effects of acute tryptophan depletion and acute phenylalanine/tyrosine depletion in healthy women. Adv. Exp. Med. Biol. 1999; 467: 67-71.
12. Walter, J.H., White, F.J., Hall, S.K., MacDonald, A., Rylance, G., Boneh, A., Francis, D.E., Shortland, G.J., Schmidt, M., Vail, A. How practical are recommendations for dietary control in phenylketonuria? Lancet 2002 Jul 6; 360(9326): 55-7.