A veterinarian has issued a stark warning that many common dog foods in the UK contain dangerous chemicals that could shorten pets' lives. A new peer-reviewed study of 15 leading pet food brands reveals that kibble and wet or canned diets are ultra-processed and contain high levels of heat-formed chemicals linked to kidney disease, diabetes, and cancer.
Study Reveals Harmful Chemicals in Dog Food
The research, conducted by the Food Quality and Safety (FoQuS) Research Group and co-authored by Dr Ciara Clarke of Butternut Box, is the first comprehensive analysis of heat-formed chemicals in commercial dog food in the UK. These chemicals, known as Advanced Glycation End Products (AGEs), are formed when proteins or fats combine during high-temperature cooking. AGEs, also called glycotoxins, accumulate with age and high sugar intake, contributing to oxidative stress and chronic disease.
Kibble and Wet Food Risks
Kibble, consumed by 54% of dogs in the UK, is cooked at temperatures up to 250C. Extreme heat processing is the primary driver of AGE accumulation, meaning food cooked at lower temperatures causes less long-term harm. Wet and canned foods, despite appearing more natural, were found to be even worse, recording the highest AGE levels of any food type tested, with concentrations of some AGE chemicals nearly six times higher than in fresh food.
Dr Ciara Clarke explained: "Most of us eat some AGEs every day, like the crust on bread or charred meat, and in small amounts, they aren't a problem. The issue for dogs is that they often eat the exact same ultra-processed meal twice a day, every day. That repeated exposure is what we should be thinking about when it comes to our dog's health."
Price No Indicator of Quality
The study found no correlation between the cost of dog food and the levels of harmful chemicals it contains. Some of the most expensive premium and prescription kibbles were among the worst performers. Fresh dog food, lightly cooked at lower temperatures and made from human-quality ingredients, showed dramatically lower levels of AGEs across every measure tested. Fresh diets also delivered more than double the lysine of kibble. Lysine is an essential amino acid critical to muscle health, immune function and overall vitality. Heat processing in kibble significantly damages this vital nutrient, meaning dogs absorb far less of it with every meal.
Dr Ciara added: "The findings are a reality check, not just for pet owners, but for an entire industry that has normalised feeding dogs ultra-processed food for generations. The science is clear: fresh, lightly cooked food is meaningfully better for dogs."
