Dietary Reduction of Advanced Glycation End Products: An Opportunity for Improved Nutrition Care.
ADVANCED GLYCATION END products (AGEs), also known as glycotoxins, are formed both exogenously and endogenously. TheMaillard reaction is an exogenous, nonenzymatic process which occurs between sugars and a free amino group of proteins, lipids, or nucleic acids when they are heat treated, resulting in AGE formation. The reaction contributes to the flavor, color, and aroma of food. A portion of food-derived AGEs are intestinally absorbed, accumulating in cells and tissues. Many types of AGEs exist, and a common dietary AGE, carboxymethyllysine is a biomarker for protein damage. Smoking is another example of an exogenous source of AGEs. AGEs form endogenously as part of normal metabolism, but pathologic changes occur when high levels of AGEs accumulate in the body. AGEs promote inflammation and oxidative stress through 4 common actions at the tissue and cellular level. First, AGEs cause stiffness of the protein matrix when they bind with cellular surfaces or cross-link with body proteins, altering function. Cross-linkage promotes renal glomeruli sclerosis, atherosclerosis, and thickens capillary basement membrane. Second, the most common AGE receptor, receptor for advanced glycation end products or RAGE, interrupts cellular signaling pathways, causing harmful tissue remodeling. Third, lipid peroxidation disrupts endothelial function, promoting oxidative stress and inflammation, which contributes to the fourth effect, a procoagulant state. AGEs naturally accumulatewith age, but levels increase in chronic diseases such as diabetes, renal disease, cardiovascular disease, Alzheimer’s disease, and rheumatoid arthritis. Available research shows AGEs contribute to the pathologyof the disease process.