Hi Dr. Barchas,
Sarah, Atlantic City, NJ
If you feed your pet a premium brand of food, the major difference between the canned and dry varieties is water content. In most cases, the two types of food are nutritionally equivalent, but canned food contains more water.
Believe it or not, that water can make a big difference to your pet’s health. Canned food is softer, and more likely to adhere to your pet’s teeth after he is done eating. Bacteria can grow on the food, and then spread into the gums, causing dental disease. And dental disease can lead to a host of other issues, including pain, chronic infection, heart disease, and kidney disease.
Although pets fed dry food may also suffer from dental disease, the process generally is slower.
Therefore, in otherwise healthy animals, I recommend a diet composed mostly of dry food. Of course, there is nothing wrong with occasional treats of wet food. But, generally, it is best if the mainstay of the diet is dry food.
In cats, there is another reason to avoid canned food. Studies have shown that feeding canned food may predispose cats to thyroid gland problems. Although the cause of this phenomenon isn’t known, the correlation has been demonstrated repeatedly.