N~ε-CARBOXYMETHYLLYSINE: IT'S ORIGIN IN SELECTED FOODS AND ITS URINARY AND FAECAL EXCRETION IN HEALTHY HUMANS'

摘要

Carboxymethyllysine (CML) was isolated and characterized almost at the same time in vivo [1] and in food products [2]. Its formation was originally described as an oxidative degradation of fructoselysine, the Amadori product found in glycated proteins. However, ten years later Fu et al. [3] found that CML was not only formed from glycoxidation but also from lipoxidation reactions. Due to the popular use of CML as a biomarker of the Maillard reaction in human tissues [4] most available studies regarding the chemical origin of CML are based on normal or pathological in vivo conditions. Bearing these limitations in mind, it has been speculated that CML would be formed primarily from lipid peroxidation reactions rather than glycation [5]. More recently a CML database subject to controversy shows that the highest CML levels have been found in food products with a high fat content (e.g. olive oil, butter) [6]. If some scientists consider that this may perhaps be a confirmation of what has been found in vivo[7], others, more skeptical, expressed doubts about the validity of the analytical method used [8,9,10]. The first objective of this paper was to take advantage of the great variability of the food composition of a single category of food (i.e. the chocolate drink mixes) to estimate which macronutrient is the main contributor to the formation of CML.