This nasty compound hides in plain sight

Cooking food has a lot of benefits compared to eating it raw. It kills off harmful bacteria, makes the food safer, improves nutrient digestibility, and improves flavour and texture. 

But too much cooking can cancel these benefits out. When we overcook our food under extreme conditions – for example, at high temperatures or for long durations –  certain nutrients can be destroyed, and it can also lead to the formation of compounds called advanced glycation end-products (AGEs).

And AGEs are bad news for our health.

You’ve probably seen AGEs with your own eyes

The browned or charred bits that form when you grill meat? Yep, those are AGEs. 

AGEs are a group of compounds that form when amino acids (the smallest units of protein) in food react with sugars (both naturally present and added sugars) during cooking. This reaction, called the Maillard reaction (pronounced “my-yar” or “my-yard”), gives food that satisfying brown colour and tasty rich flavour.

Shelf-stable, pre-packaged processed foods are also notoriously high in AGEs. These foods are often cooked at higher temperatures to make them last longer on the shelf, or to develop that crispy or crunchy texture we find irresistible.

AGEs are bad for your (and probably your cat’s) health

Many studies in humans have consistently found that people who consume more AGEs are more likely to develop chronic diseases such as cardiovascular disease, cancers, insulin resistance, dementia, liver disease, and chronic kidney disease. When people switch from a high-AGE diet to a low-AGE diet, they improve markers of inflammation and oxidative stress. So the name “AGE” is quite fitting – AGEs may actually speed up ageing!

While we don’t yet know for sure whether AGEs are harmful to cats, our cat nutrition team at KatKin, along with other renowned scientists in the field at Wageningen University, the University of Illinois Urbana-Champaign, and the University of Georgia, believe so. 

Like humans, pets also absorb AGEs from their foods. Dogs and cats fed a high-AGE diet ended up with more AGEs in their circulation. Because of this, we think that over time a gently cooked low-AGE diet, like fresh food, is likely to be healthier than a highly processed high-AGE diet, like kibble and canned food. 

Lowering AGEs with gentler cooking

AGEs are so harmful to us humans that there’s actually a practical guide, backed by science and developed by physicians and scientists at Mount Sinai Hospital in New York, on how to cook and choose foods to minimise AGE intake. The guide suggests gentler cooking with moist heat like steaming, poaching and stewing, as well as cooking for shorter times and at lower temperatures. At KatKin, we use a gentle cooking process that checks all these boxes. 

The University of Georgia has also confirmed that fresh pet food has a lower amount of AGEs than canned food. However, the fresh diet examined in the study was formulated for dogs, which typically have lower protein content than diets formulated for cats. Since higher protein levels can contribute to increased AGE formation during cooking, the findings might not fully represent the true AGE formation in cat diets. 

Additionally, the fresh diet in this study was cooked for 10 hours, which is much longer than our cooking process. And so the results in this study might not reflect the AGE amounts in our food at KatKin.

Processing impacts lysine content

Lysine is the main amino acid used in the Maillard reaction which forms AGEs. When lysine participates in AGE formation, it can no longer be fully digested or absorbed by the cat as a nutrient. Cats need lysine for healthy growth and maintenance. They can't make lysine on their own and must get it from their food. To understand how much lysine in a diet is truly available for the cats, scientists measure the ratio of reactive lysine (still available as a nutrient) to total lysine (RL:TL ratio).

But there are no official rules requiring pet food companies to report this RL:TL ratio. So when you check a pet food label for lysine content, it usually only shows the total amount, which includes the portion that cats can't absorb or use as a nutrient. Which means that cats might be at a higher risk of lysine deficiency when the RL:TL ratio is low – definitely a concern for our cats! And another reason why minimally processed foods may be the best choice for your cat’s health.

KatKin’s plan to measure AGEs

In theory, AGEs and the RL:TL ratio in all KatKin recipes should be significantly lower than those in kibble and canned foods because of the way we cook our recipes. 

This is critical, because AGEs have been shown to be harmful to health in humans (and likely cats), while the RL:TL ratio will determine the true availability of lysine, which is an essential nutrient that cats must get from their diet. 

But we can’t be 100% sure until we have the real numbers. That’s why KatKin is sending food samples to a laboratory, where we will measure them head-to-head against kibble and canned samples from market-leading brands. Keep your eyes peeled for the results!