What's really in your dog's food?
A landmark university study measured harmful compounds in 41 UK dog foods. The results might change how you think about what goes in the bowl.
Every time dog food is cooked, a chemical reaction starts. It's called the Maillard reaction, the same process that browns toast and caramelises onions.
In small amounts, it's harmless. But when food is blasted at extreme temperatures, it produces harmful compounds, including Advanced Glycation End Products (AGEs), linked to chronic inflammation, kidney damage and accelerated ageing in dogs. And reactive dicarbonyl compounds that can damage DNA.
A 2026 study from Hacettepe University, published in the Journal of Animal Physiology and Animal Nutrition, compared these compounds across 41 commercial dog foods available in the UK. It's the most comprehensive analysis of its kind.
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The data, side by side
Researchers used gold-standard LC-MS/MS laboratory methods to measure harmful compounds across all food types. Here's what they found.
Essential lysine: kept or destroyed?
Lysine is an essential amino acid your dog can't produce on its own. It's critical for muscle repair, immune function and growth. The study measured how much survives processing, and how much is damaged by heat.
CEL: the advanced glycation end product that matters most
Of the two AGEs measured (CML and CEL), CEL is the clearer indicator of harmful thermal processing. It's formed when methylglyoxal (a DNA-damaging compound) reacts with lysine at higher temperatures. The study found that fresh food kept CEL formation remarkably low, even with its high protein content.
Furosine: measuring the damage you can't see
Furosine is a marker of early glycation, the first stage of the Maillard reaction, when sugars bond to proteins and start degrading them. Higher furosine means more nutritional damage has already occurred, even before the food reaches your dog's bowl.
What about "shelf-stable fresh"?
Some brands claim their food is "fresh", even though it sits on a shelf at room temperature for months. The study tested freeze-dried food too, and the results were striking.
The researchers concluded something had happened to these ingredients before the freeze-drying step, likely a thermal pre-treatment, or ongoing chemical reactions during room-temperature storage.
Why this matters for your dog
Dogs don't get to vary their diet the way we do. Most eat the same food at every meal, every day, for years. If that food contains elevated levels of AGEs and reactive compounds, those exposures accumulate over a lifetime.
Research has shown that dogs fed higher-AGE diets had elevated AGE concentrations in their blood plasma. These compounds aren't just passing through. They're being absorbed, building up, and driving persistent low-grade inflammation.
How your dog's food is made matters just as much as what's in it.
Fresh, gently cooked, frozen fast.
At Different Dog, we cook with real ingredients at low temperatures and freeze immediately, locking in nutrition and stopping harmful compounds before they form.
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Source: Kocadağlı, T., Clarke, C. & Gökmen, V. (2026). A Comparative Analysis of Maillard-Derived α-Dicarbonyl Compounds and Advanced Glycation End Products in Fresh, Wet, Kibble, and Freeze-Dried Dog Foods. J. Anim. Physiol. Anim. Nutr. doi: 10.1111/jpn.70053. Open access, peer-reviewed.