Absolutely! Unfortunately, diet can also critically hinder their immune system.

Recently, there have been news articles about a new respiratory disease affecting dogs. As a result, many dog owners are asking how to boost their dog’s immune system. While this concern is understandable, it’s more effective to support our dog’s immune systems daily rather than just waiting for a disease outbreak to boost it. 

Having a strong immune system is crucial for maintaining good health and building resistance against various viral and bacterial infections. Our furry friends are constantly exposed to viruses, and many diseases can cling to their owners’ clothing and be brought into their homes, making it possible for their dog to become infected by a dog they have never met.

As with humans, a dog’s immune system is heavily influenced by its diet. Therefore, it is crucial to provide them with a balanced diet that supports their immune system. This article aims to provide you with the necessary information to ensure that your dog’s diet is optimized to keep their immune system healthy. While a good diet alone may not guarantee your dog’s health, it can provide the necessary foundation to lessen the chance of them getting sick.


immune system
: the bodily system that protects the body from foreign substances, cells, and tissues by producing the immune response and that includes especially the thymus, spleen, lymph nodes, special deposits of lymphoid tissue (as in the gastrointestinal tract and bone marrow), macrophages, lymphocytes including the B cells and T cells, and antibodies-Merriam Webster

This will be an extremely basic overview but I feel it is important to understand how to best provide support. Very simply, the immune system is present to protect the body from potentially harmful invaders such as bacteria, viruses, parasites, and cancer cells. When the immune system detects invaders, the body produces white blood cells, such as lymphocytes. These cells identify the invader and produce antibodies to fight it. The antibodies that are produced to fight the infections are remembered and stored so the body knows how to fight off that invader if they are exposed in the future. 


All of them! While we often think of the spleen and digestive system when we think of the immune system, it’s much more complex than that. Every single cell in the body and all organ systems have components of immunity. 

Skin is the largest organ in your dog’s body and acts as a physical barrier against disease. Beyond that, the hair follicles produce an oily substance called sebum which inhibits the growth of some bacteria and fungi

Mucosal barriers are the inner linings of several organs including the GI tract, lungs, urethra, bladder, mouth, and nose that trap invaders. In some cases, this thick layer of mucus may even kill the invaders.

The GI tract is involved in many functions of the immune system from beginning to end. As discussed above, the mucosal lining of the mouth can trap and kill germs. If those germs make it past the mouth, they will be met with the acidic environment of the stomach which is an effective barrier to many germs. The intestinal tract is also coated with mucus to trap germs. Another important factor of the GI tract concerning immune function is the gut microbiome which is responsible for many body processes but in this context, it produces biochemicals that destroy pathogens. 

Lastly, the intestinal tract is the home of GALT (gut- gut-associated lymphoid tissue) which is an accumulation of lymph cells that recognize incoming foreign particles. GALT is the largest immune organ in the body. Some sources consider GALT to be a mucosal barrier. 

The lungs also have a mucosal lining but they also have tiny hairs that work with actions such as sneezing and coughing to “eject” things that don’t belong there. Some of the immune functions of the lungs are activated by mechanical stretching which indicates that exercise is beneficial to the immune system function. 

The liver is the main organ for processing and eliminating all sorts of toxins, which most already know but it is also supplied with lymphoid tissues along with macrophages, cells that consume unwanted things. 

The spleen produces white blood cells and controls their levels in the bloodstream. It also filters the blood to remove old or damaged red blood cells. When it filters the blood, it can also trap bacteria and foreign proteins from circulating. 

Thyroid hormones regulate the activity of neutrophils which are a type of white blood cell. 



As you can see, there are many parts of the body involved in your dog’s immune system and how it functions. For the immune system to be the strongest it possibly can be, all of those body systems and organs need to be in tip-top shape. 

The most important thing when it comes to supporting your dog’s immune system is providing a well-balanced diet whether it be kibble, canned, freeze-dried, home-cooked, or raw. Despite what is often circulated in the dog food world, nutrients DO matter and not providing them can be detrimental to your dog’s ability to cope with disease. 

“ It has since been established that the complex, integrated immune system needs multiple specific micronutrients, including vitamins A, D, C, E, B6, and B12, folate, zinc, iron, copper, and selenium, which play vital, often synergistic roles at every stage of the immune response.”

Gombart AF, Pierre A, Maggini S. A Review of Micronutrients and the Immune System-Working in Harmony to Reduce the Risk of Infection. Nutrients. 2020 Jan 16;12(1):236. doi: 10.3390/nu12010236. PMID: 31963293; PMCID: PMC7019735.

It is important to note that while these nutrients are the ones that play the biggest role, that is not to say that other essential nutrients are less important. The best way to ensure that your dog thrives is by providing a complete and balanced diet. 


It is unfortunately not uncommon to see signs of a compromised immune system in dogs, especially those eating commercial diets or unbalanced home-prepared diets. Some signs to look out for include:

  • Allergies
  • Diarrhea
  • Hair loss
  • Weight loss
  • Vomiting
  • Irregular heartbeat
  • Frequent infections/ illnesses
  • Leaky gut
  • Inflammation


It’s essential to ensure that your dog’s diet contains all the nutrients they require to stay healthy. Unfortunately, home-prepared diets often lack critical nutrients that are necessary for your dog’s organs to function correctly. After analyzing several diets, I have found that most of them are dangerously low in zinc, manganese, selenium, copper, iodine, iron, vitamin E, and Vitamin D. Additionally, if liver is not included in the diet, it will be deficient in vitamin A. These deficiencies can considerably limit your dog’s immune system, making them susceptible to various diseases. Therefore, it’s crucial to formulate home-prepared diets to meet the nutritional requirements set forth by the NRC.

Commercial dog foods are specifically formulated to provide essential nutrients in appropriate amounts when fed in the recommended quantities. However, adding small amounts of fresh foods to your dog’s diet can be beneficial in increasing valuable nutrients. If you need assistance in selecting the right ingredients to add to your dog’s commercial diet, a topper formulation would be a good option. 

If you’re already feeding a well-balanced diet and want to add immune-boosting foods you may consider increasing fruits and vegetables (if your dog tolerates the extra fiber). Red-bell peppers, strawberries, blueberries, carrots, broccoli, and spinach are just some examples of beneficial fruits and veggies high in antioxidants and phytonutrients. Dogs fed a kibble diet may also benefit from the addition of preformed omega-3 fatty acids aka fish oil. Lastly, since the majority of a dog’s immune system is in the gut, your dog may benefit from the addition of a good-quality probiotic.

Beyond nutrition, ensuring your dog is getting enough exercise is extremely important. Keeping stress levels low also helps immensely.

If you’d like to boost your dog’s immune system through food, a personalized formulation may be beneficial. You can find a list of my services here. If you are unsure what service is best for your dog, please contact me! 

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