Dietary intake associated with serum versus urinary carboxymethyl-lysine, a major advanced glycation end product, in adults: The Energetics Study

Background/Objectives:Advanced glycation end products (AGEs) are implicated in the pathogenesis of atherosclerosis, diabetes and kidney disease. The objective was to describe dietary intake, the dominant source of exposure to AGEs, with carboxymethyl-lysine (CML), a major AGE, in serum and urine, respectively.Subjects/Methods:Serum and urinary CML were measured in 261 adults, aged 21-69 years, and compared with diet as assessed by six separate 24-h dietary recalls.Results:Median (25th, 75th percentile) serum and urinary CML concentrations were 686 (598, 803)μg/l and 1023 (812, 1238) g/gm creatinine. There was no correlation between serum and urinary CML (r=0.02, P=0.78). Serum CML was positively correlated with intake of soy, fruit juice, cold breakfast cereal, non-fat milk, whole grains, fruit, non-starchy vegetables and legumes, and negatively correlated with intake of red meat. Intake of fast food was not significantly correlated with serum CML. Urinary CML was positively correlated with intake of starchy vegetables, whole grains, sweets, nuts/seeds and chicken, and negatively correlated with intake of fast foods. Intake of AGE-rich foods such as fried chicken, French fries, bacon/sausage and crispy snacks were not significantly correlated with serum or urinary CML, except for a significant negative correlation between fried chicken and serum CML.Conclusions:These findings suggest that the high consumption of foods considered high in CML is not a major determinant of either serum or urinary CML. Further work is needed to understand the relationship of AGEs in blood and urine with the metabolism of dietary AGEs.