Advanced Glycation End Products (AGEs) in Food

What are AGEs?

Advanced Glycation End Products are chemical compounds formed when proteins or fats combine with sugars at high temperatures, a process known as the Maillard reaction. The browning on toast, the crust on a steak, the golden surface of crisps. These are all visible signs of AGE formation.

Your body produces small amounts of AGEs naturally as part of normal metabolism. The problem is dose. Dry-heat cooking methods -- grilling, frying, roasting, and industrial extrusion -- generate dramatically more AGEs than water-based methods like steaming, poaching, or stewing. The key drivers are temperature, low moisture, and duration rather than whether cooking is industrial or domestic. The same base ingredient can produce vastly different AGE levels depending on how it is prepared.

Once formed, AGEs are remarkably stable. They survive digestion largely intact, meaning that what enters your mouth reaches your gut in much the same chemical form. Roughly 10% of dietary AGEs are absorbed into the bloodstream, where they accumulate in tissues over years. The body can clear some, but chronic overconsumption overwhelms these repair mechanisms.

How AGEs damage your gut

The primary damage pathway runs through the RAGE receptor (Receptor for Advanced Glycation End Products), a pattern-recognition receptor found on the surface of gut epithelial cells, immune cells, and endothelial cells. When AGEs bind to RAGE, they trigger the NF-κB signalling cascade, one of the body's central inflammatory pathways.

This cascade has several downstream effects in the gut. First, it disrupts tight junctions, the protein seals between neighbouring gut epithelial cells that control what passes from the intestinal lumen into the bloodstream. When tight junctions loosen, the gut becomes more permeable, allowing bacterial fragments and undigested food particles to cross into circulation and provoke immune responses elsewhere in the body.

Second, AGE-driven inflammation alters the composition of the gut microbiome. Research shows a reduction in butyrate-producing bacteria, the species that ferment dietary fibre into butyrate, a short-chain fatty acid that serves as the primary fuel source for colonocytes (the cells lining your colon). Without adequate butyrate, these cells become energy-starved, weakening the barrier from the inside.

Third, AGEs cross-link with collagen and other structural proteins in the gut wall, stiffening the tissue over time. This reduces the gut's ability to stretch and contract normally, impairing motility and nutrient absorption. The effect is cumulative and largely irreversible once established.

Common in

• Puffed cereals
• Deep-fried snacks
• Processed cheese
• Roasted nuts
• Ready meals

Related mechanisms