Free Fructose Intake Decreases Soluble RAGE Receptor (sRAGE) and Glyoxal and Methylglyoxal Urinary Excretion on Healthy Volunteers

Abstract

Abstract Objectives Free fructose but not total fructose intake could contribute to the formation of advanced glycation end products (AGEs) and Maillard reaction products in the intestinal lumen. Therefore, the aim of this study was to compare serum levels of fructosamine, soluble receptor for AGEs (sRAGE), and urinary levels of glyoxal and methylglyoxal after free fructose and total fructose intake. Methods This is a randomized crossover study, approved by the Institutional Committee of Bioethics in Research of the University of Guanajuato (CIBIUG). Twelve clinically healthy subjects, 20–30 years old, were recruited. During the first visit, participants were randomly assigned to one of two treatments, an oral load of fructose (40 g) or total fructose (40 g fructose and 40 g glucose), in addition to their assigned treatment subjects received 25 g of hydrolyzed protein (Nature Best Isopure®) After a washing period (one week), participants were crossed over to receive the other treatment. Blood and urine samples were collected at baseline and after three hours of the oral load of each treatment. Glucose, creatinine, and lipids serum levels were measured with commercial kits. Insulin, fructosamine, and sRAGE serum levels were determined with ELISA commercial kits. Glyoxal and methylglyoxal urine levels were quantified by HPLC. Data analysis was completed using STATISTICA 10 and IBM SPSS Statistics 24.0 software. The results were considered significant with a value of P < 0.05. Results After free Fructose intake, participants had a significant decrease in sRAGE (1327 pg/L vs 1282 pg/L, P = 0.028), and in urine levels of glyoxal (0.63 ng/mg vs 0.24 ng/mg P = 0.028) and methylglyoxal (0.42 ng/mg vs 0.13 ng/mg P = 0.002). After Fructose and glucose intake, participants only had a significant decreased in serum sRAGE (1256 pg/L vs 1199 pg/L, P = 0.015). Fructosamine did not showed a difference after either intervention. Conclusions The consumption of free fructose decreased serum sRAGE levels, as well as urinary excretion of glyoxal and methylglyoxal. These results may suggest a possible in vivo formation of AGEs by consuming free fructose. Nevertheless, more studies are necessary to assess the formation of methylglyoxal derived AGEs. Funding Sources This project was supported by the University of Guanajuato through the Research and Postgraduate Support Department (DAIP).