Aspartame and Phe-Containing Degradation Products in Soft Drinks across Europe

Abstract

Phenylketonuria and tyrosinemia type 1 are treated with dietary phenylalanine (Phe) restriction. Aspartame is a Phe-containing synthetic sweetener used in many products, including many ‘regular’ soft drinks. Its amount is (often) not declared; therefore, patients are advised not to consume aspartame-containing foods. This study aimed to determine the variation in aspartame concentrations and its Phe-containing degradation products in aspartame-containing soft drinks. For this, an LC–MS/MS method was developed for the analysis of aspartame, Phe, aspartylphenylalanine, and diketopiperazine in soft drinks. In total, 111 regularly used soft drinks from 10 European countries were analyzed. The method proved linear and had an inter-assay precision (CV%) below 5% for aspartame and higher CVs% of 4.4–49.6% for the degradation products, as many concentrations were at the limit of quantification. Aspartame and total Phe concentrations in the aspartame-containing soft drinks varied from 103 to 1790 µmol/L (30–527 mg/L) and from 119 to 2013 µmol/L (20–332 mg/L), respectively, and were highly variable among similar soft drinks bought in different countries. Since Phe concentrations between drinks and countries highly vary, we strongly advocate the declaration of the amount of aspartame on soft drink labels, as some drinks may be suitable for consumption by patients with Phe-restricted diets.

A 3 Year Longitudinal Prospective Review Examining the Dietary Profile and Contribution Made by Special Low Protein Foods to Energy and Macronutrient Intake in Children with Phenylketonuria

“…Many ‘sugar free’ drinks are unsuitable for children with PKU as they contain aspartame, a source of phenylalanine, limiting choice and increasing the glycaemic index of foods consumed. Importantly, the aspartame content of drinks may vary significantly, and the phenylalanine content is not identified on the food label [ 31 ].…”

Accidental Consumption of Aspartame in Phenylketonuria: Patient Experiences

“…Recently Dutch researchers demonstrated there was wide variability in the aspartame content of soft drinks, particularly the same brand of soft drinks bought in different countries. They have urged European legislators to enforce manufacturers to declare the amount of phenylalanine obtained from aspartame on food and drink labels, so that individuals with PKU are aware of the phenylalanine content of foods and drinks [ 24 ]. This ‘call for action’ is supported by NSPKU Medical Advisory Panel of dietitians [ 25 ].…”

Additives in Children’s Nutrition—A Review of Current Events

“…Food additives that are used to improve sweetness with or without adding extra calories are called sweeteners [ 102 , 103 , 104 , 105 ]. Aspartame (E-951) is an artificial sweetener used as a substitute for sugar and it is present in several sugar-free products, as well as in some medications and vitamin supplements [ 102 , 103 , 104 ].…”

“…It is added to nonalcoholic and alcoholic beverages, which most often bear the indication “zero sugar” [ 105 ].…”

“…The conversion of phenylalanine to tyrosine is successful, so phenylalanine accumulates in the blood and brain, which can lead to negative consequences for the child’s neurological development. If a deficiency of this enzyme is determined, absolute restriction of the consumption of all products containing phenylalanine or compounds that are metabolized to phenylalanine in the body is advised [ 105 ]. The safety of aspartame has been studied since its discovery and is one of the most rigorously tested food ingredients [ 106 ].…”