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At Healthfully, we strive to deliver objective content that is accurate and up-to-date. Our team periodically reviews articles in order to ensure content quality. The sources cited below consist of evidence from peer-reviewed journals, prominent medical organizations, academic associations, and government data.
- "Critical Reviews in Toxicology"; Aspartame: A Safety Evaluation Based on Current Use Levels, Regulations, and Toxicological and Epidemiological Studies; B. Magnuson, et al.; 2007
- "Critical Reviews in Toxicology"; Aspartame: A Safety Evaluation Based on Current Use Levels, Regulations, and Toxicological and Epidemiological Studies; B. Magnuson, et al.; 2007
- MayoClinic.com; Phenylalanine in Diet Soda: Is it Harmful? Katherine Zeratsky, R.D.; February 2011
The information contained on this site is for informational purposes only, and should not be used as a substitute for the advice of a professional health care provider. Please check with the appropriate physician regarding health questions and concerns. Although we strive to deliver accurate and up-to-date information, no guarantee to that effect is made.
About the Dangers of Phenylalanine
You may see warnings on diet soda bottles about the risks of phenylalanine. An essential amino acid used to make proteins as well as brain chemical and some hormones, phenylalanine occurs naturally in many foods, including meats, dairy products and fish. Phenylalanine poses a health risk only if you have a health disorder called phenylketonuria or if you take high doses of phenylalanine supplements 1.
If you are experiencing serious medical symptoms, seek emergency treatment immediately.
Phenylketonuria and Phenylalanine
If you have a genetic disorder known as phenylketonuria, you should not consume phenylalanine. People with PKU lack an enzyme, phenylalanine hydroxylase, that breaks down phenylalanine into other substances the body needs and uses. If you have PKU, levels of phenylalanine build up in your body, which can cause mental retardation and developmental delays. Around one in 25,000 babies born in the United States has PKU, according to the March of Dimes 1. In the United States, all babies undergo testing for PKU before leaving the hospital. A special diet that limits phenylalanine can prevent damage from PKU.
- If you have a genetic disorder known as phenylketonuria, you should not consume phenylalanine.
- People with PKU lack an enzyme, phenylalanine hydroxylase, that breaks down phenylalanine into other substances the body needs and uses.
Supplemental Phenylalanine
Side Effects of Phenylalanine in Soda
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Supplemental phenylalanine may help treat vitiligo, a disease that causes patches of skin to lose their pigment. Some practitioners use phenylalanine to treat chronic pain or depression. Take supplemental phenylalanine only under your doctor's supervision, the University of Maryland Medical Center cautions 2. This supplement can cause a severe rise in blood pressure if taken with medications such as monoamine oxidase inhibitors, an older class of antidepressants. Phenylalanine might also interfere with levodopa, a medication taken to treat Parkinson's disease. High doses of this supplement, over 5,000 mg per day, can cause nerve damage, warns UMMC. In lower doses, nausea, headaches and heartburn may occur.
- Supplemental phenylalanine may help treat vitiligo, a disease that causes patches of skin to lose their pigment.
- This supplement can cause a severe rise in blood pressure if taken with medications such as monoamine oxidase inhibitors, an older class of antidepressants.
Aspartame and Phenylalanine
Aspartame, an artificial sweetener, contains phenylalanine. No evidence exists to support claims that aspartame causes a number of health problems. Studies show that aspartame does not cause cancer or nerve damage when taken in doses found in foods, according to a report published in the 2007 issue of "Critical Reviews in Toxicology" by The Burdock Group, an independent food safety and regulatory compliance consulting firm.
Pregnancy and Phenylketonuria
Foods to Avoid on a Phenylketonuria Diet
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Around 3,000 women in the United States were treated for PKU as children and then stopped the PKU diet in childhood, following doctor's recommendations at the time. If you fit this description and get pregnant, high levels of phenylalanine could cause mental retardation or small head size, called microcephaly, in your baby. Restarting the PKU diet at least three months before getting pregnant and continuing throughout pregnancy can prevent damage from phenylalanine, the March of Dimes reports 1.
Related Articles
References
- March of Dimes; PKU (Phenylketonuria); March 2008
- University of Maryland Medical Center; Phenylalanine; Steven Ehrlich; June 2009
- "Critical Reviews in Toxicology"; Aspartame: A Safety Evaluation Based on Current Use Levels, Regulations, and Toxicological and Epidemiological Studies; B. Magnuson, et al.; 2007
- MayoClinic.com; Phenylalanine in Diet Soda: Is it Harmful? Katherine Zeratsky, R.D.; February 2011
- Marble, M. Phenylketonuria and other metabolic diseases: clinical, genetic and newborn screening aspects. LSU Health Sciences Center.
- Burlina AP, Lachmann RH, Manara R, et al. The neurological and psychological phenotype of adult patients with early-treated phenylketonuria: A systematic review. J Inherit Metab Dis. 2019;42(2):209-219. doi:10.1002/jimd.12065
- Hood A, Antenor-dorsey, JA, Rutlin J, et al. Prolonged exposure to high and variable phenylalanine levels over the lifetime predicts brain white matter integrity in children with phenylketonuria. Mol Genet Metab. 2015;114(1):19-24. doi:10.1016/j.ymgme.2014.11.007
- Macleod EL, Ney DM. Nutritional management of phenylketonuria. Ann Nestle Eng. 2010;68(2):58-69. doi:10.1159/000312813
- University of Washington, Cristine M. Trahms Program for Phenylketonuria. What is the diet for PKU?
- Sara, GL., Alejandra, LML, Isabel, IG, Marcela, VA. Conventional phenylketonuria treatment. Journal of Inborn Errors of Metabolism and Screening. 2010;4. doi:10.1177/2326409816685733
- Southeast Regional Genetics Network. PKU nutrition management guidelines. Updated August 2016.
- Kose E, Aksoy B, Kuyum P, Tuncer N, Arslan N, Ozturk Y. The effects of breastfeeding in infants with ohenylketonuria. J Pediatr Nurs. 2018;38:27-32. doi:10.1016/j.pedn.2017.10.009
- Guo H, Zheng Y, Wang B, Li Z. A note on an improved self-healing group key distribution scheme. Sensors (Basel). 2015;15(10):25033-8. doi:10.3390/ijns5030026
- Concolino D, Mascaro I, Moricca MT, et al. Long-term treatment of phenylketonuria with a new medical food containing large neutral amino acids [published correction appears in Eur J Clin Nutr. 2017 Aug;71(8):1027]. Eur J Clin Nutr. 2017;71(1):51–55. doi:10.1038/ejcn.2016.166
- Kose E, Aksoy B, Kuyum P, Tuncer N, Arslan N, Ozturk Y. The effects of breastfeeding in infants with phenylketonuria. J Pediatr Nurs. 2018;38:27-32. doi:10.1016/j.pedn.2017.10.009
- Southeastern Genetics Network. PKU nutrition management guidelines.
- The National PKU Alliance. Returning to diet.
- University of Washington. Cristine M. Trahms Program for Phenylketonuria. What is the diet for PKU?
Writer Bio
A registered nurse with more than 25 years of experience in oncology, labor/delivery, neonatal intensive care, infertility and ophthalmology, Sharon Perkins has also coauthored and edited numerous health books for the Wiley "Dummies" series. Perkins also has extensive experience working in home health with medically fragile pediatric patients.