Analytical Chemistry of Impurities in Amino Acids Used as Nutrients: Recommendations for Regulatory Risk Management

Abstract

Proteinogenic amino acids are natural nutrients ingested daily from standard foods. Commercially manufactured amino acids are added to a wide range of nutritional products, including dietary supplements and regular foods. Currently, the regulatory risk management of amino acids is conducted by means of setting daily maximum limits of intake. However, there have been no reported adverse effects of amino acid overdosing, while impurities in low-quality amino acids have been identified as causative agents in several health hazard events. This paper reviews the analytical chemistry of impurities in amino acids and highlights major variations in the purity of commercial products. Furthermore, it examines the international standards and global regulatory risk assessment of amino acids utilized in dietary supplements and foods, recommending (1) further research on analytical methods that can comprehensively separate impurities in amino acids, and (2) re-focusing on the regulatory risk management of amino acids to the analytical chemistry of impurities.

Rapid indirect separation of glutamine enantiomers by micellar electrokinetic chromatography. Analysis of dietary supplements

“…The L-enantiomer is the natural form whereas the presence of D-amino acids has a special relevance since many of them are key compounds in metabolic pathways or are related to different diseases, such as Alzheimer's or cancer [1]. From a nutritional point of view, L-enantiomers are linked to the nutritional value of foods, while Denantiomers can affect the bioavailability of L-amino acids and the nutritional value of foods due to a reduction in protein digestibility [2,3]. Among the 20 proteinogenic amino acids, glutamine (Gln) is the most abundant free α-amino acid in the mammalian body (mainly in plasma and muscle) and the second most abundant in the structure of proteins [4][5][6].…”