Thank you for submitting your question to the Ask the Expert Panel of Nutricia Learning Center.
We don't think there is enough evidence to be concerned about carnitine levels in PKU patients unless your patients are not taking formula. From what we understand from the literature, low carnitine levels have mainly been found in patients who did not adhere to the diet recommendations or consumed medical food that did not contain any carnitine.
- Vileseca MA et al. Controled diet in phenylketonuria may cause serum carnitine deficiency. J Inherit Metab Dis. 1993; 16(1): 101-4.
- Sitta A et al. L-Carnitine blood levels and oxidative stress in treated phenylketonuric patients. Cell Mol Neurobiol 2009; 29(2):211-8.
Weigel et al (2008) found suboptimal carnitine status in patients consuming both medical food with and without carnitine compared to healthy control and recommends giving carnitine levels careful consideration.
- Weigel C et al. Carnitine staus in early-treated children, adolescents and young adults with phenylketonuria on low phenylalanine diets. Ann Nutr Metab 2008;53(2):91-5.
The NIH Fact Sheet on Carnitine notes that carnitine intake in vegans is 10-12 mg/d and is typically of no concern in respect to carnitine deficiency as the liver and kidney produce sufficient amounts.
- NIH Fact Sheet
The new PKU Periflex Junior Plus and TYR Anamix Next contain 24 mg/100 g product (=28 g PE), which would provide more carnitine (in many cases double) than the documented intake by vegans, so as long as patients are consuming formula with carnitine, they should be fine. The amount is lower compared to the previous Periflex Junior formulation, but the same as the current Periflex Advance product (per 10 g PE). We have no reports of carnitine deficiency in any PKU patient using our products.
Thank you again for your question. We hope you find this answer helpful for your clinical practice.Ulrike Reichert, MSDisclaimer: Please note that this answer is not meant to diagnose individual patients, and that any treatment or disorder management decisions have to be taken with your own professional experience.
Tags: Carnitine in PKU, PKU