Advanced Glycation End Products in Pet Food

Thermal processing of foods helps to increase food safety by killing bacteria, viruses and parasites. However, during the cooking process, advanced glycation end products, or AGEs, are formed from Maillard reactions when a sugar molecule binds to an amino acid. Maillard reactions may help to improve taste and appearance of the product but can also reduce the bioavailability of an amino acid, making the amino acid less available for the body to use.¹ AGEs are also associated with increased inflammation and health issues.²

A previous white paper on BSM’s website, “The Science behind Advanced Glycation End Products,” by Irene Lambregts, discusses the science behind the formation of AGEs and is a great preliminary read. This article focuses on new knowledge about how different processing methods may affect the accumulation of some AGEs not only in pet food, but in the dog’s body. The current article is an evaluation and summarization of, “The association of four differently processed diets with plasma and urine advanced glycation end products and serum soluble receptor for advanced glycation end products concentration in healthy dogs,” by Siobhan Bridglalsingh, et al.,¹ which can be found here.

This study explored how different methods of processing dog food affect concentrations of AGEs in the diets as well as in the blood and urine of healthy dogs.

The researchers tested four types of dog food:

1. Wet Food (WF): Cooked using a retort process, which uses high temperatures. (Maximum temperature of 254^oF maintained for 60 to 90 minutes)
2. Dry Food (DF): Cooked using extrusion, which uses heat and pressure. (Maximum temperature of 265^oF)
3. Air-Dried Food (ADF): Moderately processed and dried at lower temperatures. (Maximum temperature of 140^oF)
4. Mildly Cooked Food (MF): A minimally processed food, which is mildly cooked. (Maximum temperature of 105^oF for 10 hours, then frozen)

The researchers wanted to evaluate if the different processing methods would lead to dissimilar levels of AGEs in the dogs' blood and urine. Additionally, the researchers measured a protein called soluble receptor for advanced glycation end products (sRAGE), which can help neutralize AGEs and prevent inflammation.² Low sRAGE concentrations in humans are associated with chronic disease like diabetes, hypertension, and adiposity (obesity).² This may be because sRAGE proteins are being used to bind AGEs in the body, which decreases their free concentration, which is what was measured.

The paper’s significant findings:

• Dietary AGEs: WF had the highest AGE concentration, followed by ADF.
• Plasma AGEs: Dogs consuming WF had the highest concentrations of AGEs in their blood, followed by those consuming ADF. Dogs consuming DF and MF had lower concentrations.
• Urinary AGEs: The lower-moisture foods (DF and ADF) were associated with higher urinary AGE concentrations compared to the WF and MF with higher moisture.
• Serum sRAGE: The concentrations of sRAGE did not change significantly based on the type of food.

A major limitation of this study was that that these diets were previously formulated and available on the market, so they had different nutrient components and were made with different ingredients. Therefore, it is impossible to know if the processing methods or the ingredients and nutrient make-up of the diet caused variations in AGE concentrations. However, because the diets used may be considered typical representations for those types of diets, this study provides an adequate foundation for future studies to build off. Another limitation of this study is that it only evaluated results in eight beagle dogs, and this sample size does not lend itself to fantastic statistical power.³

The way dog food is processed may impact the levels of AGEs in dogs. In this referenced study, no clinical effects were associated with higher AGE concentrations, and all dogs were healthy throughout the study. Wet foods in this study tended to increase these levels the most. To help reduce dietary AGEs, which are associated with inflammation, the next steps would be to investigate if dietary components, including the amount and type of protein and carbohydrate in these diets, affect AGE concentrations.

References:

1. van Roojin, C., Maillard reaction products in pet foods. Animal Nutrition, Food Chemistry, WIAS. Research output: Thesis. https://research.wur.nl/en/publications/maillard-reaction-products-in-pet-foods
2. Bridglalshingh, S., Archer-Hartmann, S., Azadi, P., et al. 2024. Association of four differently processed diets with plasma and urine advanced glycation end products and serum soluble receptor for advanced glycation end product concentration in healthy dogs. J. Anim. Physiol. Anim. Nutr. 108:735-751.
3. Clinician’s Guide to Understanding Effect Size, Alpha Level, Power, and Sample Size. Peterson, SJ, Foley, S. Nutr Clin Pract. 2021 Jun; 36:598-605.

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About the Author

Renee Streeter is a Doctor of Veterinary Medicine and a Diplomate of the American College of Veterinary Internal Medicine (Nutrition). She obtained her Bachelor's degree in Animal Science from Cornell University and served as a farm animal nutritionist for a major feed company before attending veterinary school at Ross University. Her clinical rotations were done at Cornell University’s college of veterinary medicine, where she stayed on to do her Clinical Nutrition residency. While working in a large general practice and doing clinical nutrition consultation, Dr. Streeter also founded her own veterinary nutrition consulting company and currently helps industry clients through her position as the Nutrition Practice Principal at BSM Partners.