Antioxidants play a double role in dog food, both preserving the food and benefiting the animals’ health. However, the relationships among ingredients and associated changes in the antioxidant levels in dogs’ bodies may be complicated. A collaboration of Colombian researchers observed that dog foods with different antioxidant levels didn’t have the effects on dogs’ blood chemistry that the scientists had predicted.

Antioxidants in dog food

Dog foods contain fats, oils and other lipids that can go bad or rancid, resulting in unwanted changes in odor, flavor and color. This decreases the dog foods’ shelf life and can cause pets to reject the food. Natural or synthetic antioxidants can help prevent this spoilage. 

At the same time, antioxidants in dog food can counteract free radicals and certain oxygen molecules, called reactive oxygen species, in dogs bodies. An imbalance in the reactive oxygen types and antioxidants is called oxidative stress. Within dogs’ bodies, oxidative stress can alter the structure of DNA, proteins and other molecules, leading to cell degeneration associated with aging, diabetes mellitus, osteoarthritis, kidney disease and cancer.

Experiment on kibble formulation and oxidative stress in dogs

In the Journal of Vetirinary Medicine and Science, the Colombian scientists noted that little research has focused on how variations in dogs’ diets can influence pets’ levels of oxidative stress.

To explore the relationship among dog food ingredients and oxidative stress, the scientists conducted an experiment using six Beagles. Each dog ate one of four dry foods for five weeks, then switched to each of the other formulations. The formulations varied in their antioxidant profiles. Every dog ate each formulation for five weeks, and every week the researchers tested the dogs’ blood for total phenolic content, total antioxidant capacity, reactive oxygen species and cytotoxicity.

The scientists observed that although kibble affected the oxidative/antioxidant profile of blood plasma in dogs, the specific antioxidant levels of the dog food did not appear directly related to those changes. The antioxidant profile of the dogs blood seemed to be influenced by the diet’s nutritional profile and the act of eating it. However, the largest effect seemed to result from the individual dogs themselves. The scientists concluded that the biological process relating dog food formulation to oxidative/antioxidant equilibrium in dogs remains unclear.