Immune and Digestive Health in the Mature Dog

Posted by David Galvez on

Legal Disclaimer- In compliance with Health Canada and FDA regulations, none of our Veterinary Health Products are intended to diagnose, treat, cure, or prevent any disease. The information on this page is presented for educational purposes only.


Thanks to tremendous advances in nutrition and preventive medicine, our beloved dogs live longer and healthier lives. Depending on their breed and size, dogs age at different rates. A giant dog may be considered senior at 5, a large dog at 7, and a small dog at 9 years old. You can use the AAHA Age Calculator to determine your own dog's human equivalent age. 

Some aging changes are easy to spot, like a greying face or your dog slowing down on walks. Other aging changes, like a decrease in immune function, happen without clear signs but can significantly impact your dog's health. As our beloved dogs age, their immune system is not as effective, leaving them susceptible to harmful pathogens and bacteria.

The primary component of your dog's immune system is their gut microbiome. Studies show that up to 70% of a pet's immune system is contained in the digestive system, making nutrition and gut health essential for maintaining the overall health of your mature or senior dog (1).


Your dog's gastrointestinal tract (GI tract) is home to a unique collection of hundreds of different species of bacteria and other microbes, collectively called their gut microbiome. The term "microbiome" refers to both the bacterial cells and their genetic material (3).

The microbiome has such a profound effect on the health of dogs (and people!) that it is now recognized as an organ (3). Each dog has an entirely unique microbiome (5). Your dog's microbiome modulates the immune system, protects against harmful pathogens, and provides nutritional benefits (6).

The gut microbiome is also a key component of your dog's ability to maintain a healthy immune system (2). A healthy and stable microbiome can simultaneously act as both pro-and anti-inflammatory, preventing excessive inflammation while also responding to infections promptly (2).

The main organ in your dog's digestive system is the small intestine. Vitamins, minerals, proteins, fats, and carbohydrates are all absorbed by the small intestine. This critical organ has many cells that aid in digestion as well as beneficial bacteria for gut health (4).

The microflora (or beneficial bacteria) in your dog's intestine play a critical role in how your dog's immune system functions (3). The intestine is host to an estimated 100 trillion microbial cells, which is 10 times the number of cells in your dog's entire body! (5). Gastrointestinal microbial diversity has been shown to decrease with age. That decline is associated with increased frailty, reduced general health and cognitive function (2).


Adding clinically-proven probiotics is a safe and efficient way to support the microbiome of your mature dog. Our proprietary Senior Immunity Omega blend, included on our Shield Again formula, is the first brand of Veterinary Health Products in Canada containing DE-111 Probiotic*, a patented strain of Bacillus subtilis. DE-111 Probiotic has been tested in randomized, double blind, placebo-controlled clinical trials demonstrating significant effect modulating a positive gastrointestinal and Immunomodulatory response in healthy dogs and humans.

 *DE-111 Probiotic is trademark of Deerland Probiotics & Enzymes, Inc.


  • Omega 3 fatty acids from fish oil, particularly EPA and DHA.
  • Antioxidants provide crucial support to your dog's immune system. Vitamin E, Alpha-lipoic Acid, and a blend of pomegranate and blueberry provide a robust combination of beneficial antioxidants. 
  • Every cell in your dog's body needs energy to function properly. L-carnitine is an energy source for rapidly dividing cells, like gut cells. 
  • Beta-glucans, a family of active compounds common in the cell walls of baker's yeast, have been shown to stimulate immune responses in older dogs. Clinical studies show that adding these active cell wall components to a dog's diet can improve overall immune response.

If you believe your mature dog may have gastrointestinal or immunity health problems, consider our Shield Again formula, specifically formulated to support healthy digestion and a healthy immune system, helping your aging dog to maintain a healthy and active lifestyle.


← Older Post Newer Post →