Studies on the influence of dietary 3-deoxyglucosone on the urinary excretion of 2-keto-3-deoxygluconic acid

3-Deoxyglucosone (3-DG) is an important intermediate of the Maillard reaction in food and in vivo. Such 1,2-dicarbonyl compounds shall play a role for the development of age-related diseases as well as diabetes-related complications. As food may contain 3-DG in considerable concentrations, knowledge about the absorption and metabolism of 3-DG is required. The aim of the study was to analyze the dietary influence of 3-DG on the urinary excretion of two of its metabolites, namely 3-deoxyfructose (3-DF) and 2-keto-3-deoxygluconic acid (3-DGA). 18 participants followed a dietary protocol and collected their 24 h urine, which was subsequently analyzed with GC-MS. Urinary excretion of 3-DG, 3-DF and 3-DGA decreased by 60, 57 and 28%, respectively, when the participants changed their conventional diet to a raw-food diet virtually free of dicarbonyl compounds. Four subjects participated in a dietary intervention with honey containing 3-DG, which led to a significant increase of 3-DG, 3-DF and 3-DGA in the urine of the subjects. In comparison to 3-DG, amounts of 3-DF and 3-DGA excreted per day were 50 and 5 times higher, respectively. From the ingested amount of 3-DG, around 1.1% were excreted as 3-DG, 23.4% were excreted as 3-DF and 1.6% as 3-DGA. This indicates that 3-DF is by far the main product of the metabolism of dietary 3-DG.