Cailin Heinze, a veterinary nutritionist at Cummings Veterinary Medical Center, responds
Grain-free diets are one of the largest growing segments of the pet food market. More and more pet owners are choosing these diets, which are billed as more natural and less likely to cause health problems and allergies. It all sounds great—except that those claims are not true.
There is no reliable evidence that suggests that it’s harmful to feed grains to dogs or cats. Whole grains contain valuable dietary nutrients, including vitamins, minerals, essential fatty acids and fiber. Some grain products have protein that is easier for your pet to digest than some protein from meat. Even refined grains such as white rice can be beneficial for your pet’s health, depending on the type of diet and the pet.
The vast majority of dogs and cats are very efficient at digesting and using more than 90 percent of the nutrients from grains in the amounts typically found in pet foods. While food allergies in pets are uncommon, allergies to grains are even rarer. The small number of pets that have allergies are most often allergic to animal proteins, such as chicken, beef and dairy. Gluten intolerance is also exceedingly rare in pets. Gastrointestinal symptoms caused by consuming gluten have been confirmed in just one inbred family of Irish setters.
Grain-free diets can vary widely in terms of their nutritional profiles. Some are lower in carbohydrates, which means that they can be quite high in both fat and calories. Other grain-free diets merely substitute similar amounts of highly refined starches, such as those from potatoes or tapioca (also called cassava), in place of grains. These ingredients may provide fewer nutrients and less fiber than whole grains, and foods containing them can cost more.
Other pet food companies use ingredients such as peas, beans or lentils instead of grains to provide carbohydrates, but these ingredients are not necessarily any better for your pet than grains and may cause digestive upset in some animals.
The bottom line is that “grain-free” is a marketing concept designed to sell pet food, not an evidenced-based solution for helping your pet live a long, healthy life.
For any pet health issue, owners should contact their veterinarian. You can find more answers to common questions about pet nutrition from the Tufts Clinical Nutrition Service at Petfoodology.