Chemical Hazards Nursel Söylemez Milli · Advanced glycation end-products · Maillard reaction · dietary AGEs · 2 min read
Advanced glycation end-products (AGEs) are a heterogeneous group of compounds formed through non-enzymatic reactions between reducing sugars and the free amino groups of proteins, lipids or nucleic acids. This process, known as glycation or the Maillard reaction, is responsible for many desirable colour, flavour and aroma properties of thermally processed foods. However, the later stages of the reaction also lead to stable end-products that have been associated with adverse health effects.
The formation of AGEs proceeds through several stages. In the initial stage, a reducing sugar reacts with an amino group to form a Schiff base, which rearranges into a more stable Amadori product. In the intermediate stage, these products degrade into highly reactive dicarbonyl compounds such as glyoxal, methylglyoxal and 3-deoxyglucosone. In the final stage, these intermediates react further with proteins to form AGEs. Well-characterized examples include Nε-(carboxymethyl)lysine (CML), Nε-(carboxyethyl)lysine (CEL), pentosidine and methylglyoxal-derived hydroimidazolones. Lipid oxidation products can also contribute to AGE formation, linking glycation with oxidative processes.
AGEs are formed endogenously in the human body, but they are also consumed through the diet. Foods rich in protein and fat that are subjected to dry heat at high temperatures, such as grilled, fried, roasted and broiled meats, are among the major dietary sources. Bakery products, processed cheeses and some ready-to-eat foods also contain considerable amounts.
The health relevance of dietary AGEs is still being investigated. A portion of dietary AGEs is absorbed and can contribute to the body's AGE pool. AGEs can interact with specific receptors, particularly the receptor for advanced glycation end-products (RAGE), triggering oxidative stress and inflammatory responses. Elevated AGE levels have been associated with diabetes complications, cardiovascular disease, kidney disease, neurodegenerative disorders and ageing processes. However, the extent to which dietary AGEs contribute to these conditions in healthy individuals remains a subject of debate.
The formation of AGEs in foods depends on temperature, heating time, water activity, pH, the composition of sugars and proteins, and the presence of pro-oxidant or antioxidant compounds. High temperatures and low moisture favour formation, whereas moist cooking methods such as boiling, steaming and stewing generally produce lower levels.
Several mitigation strategies have been proposed. These include lower cooking temperatures and shorter cooking times, moist-heat methods, marinating in acidic solutions, and the addition of natural compounds such as polyphenols, flavonoids and spices that can trap reactive dicarbonyls or act as antioxidants. Reformulation and processing optimization are being studied for industrial products.
Reliable analysis of AGEs is challenging because of their structural diversity. Liquid chromatography coupled with tandem mass spectrometry is regarded as the most accurate method, while immunochemical and fluorescence-based methods are used for screening. Further research is needed to establish standardized methods, reliable food composition databases and a clearer understanding of the health effects of dietary AGEs.