Can a change in diet improve your dog’s immune status? The answer is a very qualified “maybe.”

A balanced diet is essential for a healthy immune system, but it’s easy to go overboard with supplements, trying to ensure your dog’s best health.

“Nutrition is vital for optimal immune function. Proteins, fats, and many vitamins and minerals are necessary for immune cells and molecules. Most pet foods are formulated to have more than adequate amounts of nutrients for normal immune function,” says Dr. John Loftus, assistant professor of small animal medicine and of nutrition in the Department of Clinical Sciences.

“There are some cases where supplementing a dog’s diet might be beneficial to support normal immune function,” says Loftus. “Your pet’s primary veterinarian or a veterinary nutritionist can provide recommendations for an individual pet. Some nutrients that play important roles in the immune system, like vitamin D, can be supplemented in excess, so I don’t recommend supplementing additional vitamins or minerals without checking with a vet.”

GI help

A major area of concern for immune health is your dog’s gastrointestinal (GI) tract. The whole lining of the GI tract is open to the outside world, and it acts to stop any pathogenic bacteria from getting access to your dog’s organs and bloodstream. Scientists estimate that approximately 70-90% of the immune system resides in the gut. The use of probiotics can help a dog with a weak immune system gain some protection (— and some veterinarians suggest using a probiotic routinely).

Probiotics increase the production of short-chain fatty acids in the gut, such as lactic acid and acetic acid. Those fatty acids discourage the growth of pathogenic bacteria. They may include cultures of beneficial bacteria. These factors help increase “good bacteria” and prevent the overgrowth of “bad bacteria.” These dynamics shape a system referred to as the “gut microbiome.”

Probiotics are very safe, so they are one of the most frequently recommended supplements. They
can help a dog who has a temporary case of diarrhea, ease a dog through stressful periods (such as a move to a new home), and they can provide relief to a dog undergoing chemotherapy (when their immune system has been weakened by treatment).

However, it is important to stick to canine probiotics. Human probiotics are geared toward different gut bacteria. Most veterinarians will recommend a product with a variety of helpful bacteria included in it, instead of just one strain.

Another supplement that is considered generally safe and can be helpful for dogs with stressed or weakened immune systems is the addition of omega-3 fatty acids. Fish oils are the usual source, but you should double-check to make sure that the products do not contain heavy metal contamination. Follow the directions closely, otherwise giving your dog too much could lead to loose stools.

Bottom line

The bottom line for supporting the immune health for your dog is to feed them an appropriate, balanced and complete diet. If you choose to cook for your dog, consult a veterinary nutritionist for a balanced recipe. A dog with an immunocompromised illness should avoid a raw diet due to the increased exposure to bacteria.

You can add some fresh food items to your dog’s food if you feed a commercial diet but remember the 10% rule: no more than 10% of their diet should be “extras,” or else you may destroy the balance of their diet.

Pro-immunity extras include red-bell peppers, berries (such as strawberries and blueberries), as well as spinach, carrots or kale. Many dogs will take these offerings as training treats, or they can be added to their meals.

If you feel that your dog needs immune support beyond this level, consult your veterinarian.

You can also submit a consultation request to the Small Animal Clinical Nutrition Service, run by the Loftus Lab at the Cornell University College of Veterinary Medicine.

This article has been reprinted with permission from the Cornell University College of Veterinary Medicine’s DogWatch newsletter, published by Belvoir Media Group. When you become a member of the Riney Canine Health Center, you will receive a free subscription to DogWatch.