In internal medicine, we see a lot of chronic gastrointestinal (GI) diseases. Chronic GI diseases is defined by symptoms occurring for three months or longer. These symptoms may be off and on, or consistent. When there is chronic inflammation or disease within the GI tract, it can lead to nutrient or vitamin deficiency. Low cobalamin, or vitamin B₁₂, is common in both dogs and cats with GI disease. It can be caused either by diffuse inflammation, or inflammation that is “all over” the small intestinal tract, or severe distal inflammation, or inflammation that is further down the GI tract in a more specific area of the intestines. Identifying low cobalamin, can assist your veterinarian in identifying where your pet may be experiencing inflammation within their intestinal tract.
So let’s back up a little bit. What does this all mean, and why is it important? Cobalamin is a water-soluble vitamin that is absorbed by the portion of the small intestines called the ileum. Your pets receive this vitamin through their balanced commercial diets. Vitamin B₁₂ is found within many meats, dairy, and eggs, and pet food diets. Vegetarian and vegan diets do not contain cobalamin unless otherwise supplemented, so be sure to read your pet food labels. Why do your pets need this though? Cobalamin is required for metabolism of carbon, so when depleted, your pet will experience increased levels of methylmalonic acid, and amino acid disturbances. These imbalances can contribute to some of the symptoms you may be noticing from your pet. Common symptoms are lethargy, weight loss, decreased appetite, vomiting, diarrhea, and sometimes, if severe enough, even neuropathies can be noted. If cobalamin deficiency is severe enough, some of these patients will not respond to therapy until they are supplemented with vitamin B₁₂.
Some breeds of dogs are predisposed to having low cobalamin; Australian shepherds, beagles, giant schnauzers, borders collies, and Chinese shar-peis.
When pets experience inflammation of their GI tract, the receptors responsible for absorbing cobalamin from your pet’s diet become damaged, and cobalamin cannot be properly absorbed. If pets experience excessive diarrhea, cobalamin can also be lost due to fluid losses. Combine these losses with decreased appetite or anorexia, and severe depletion can occur.
To test for these losses, your veterinarian may recommend a blood test to measure serum cobalamin levels within your pet’s blood.Vitamin B₁₂ was thought to be best absorbed through subcutaneous injections if malabsorption was suspected, but recent studies have shown that B₁₂ can effectively supplemented with either subcutaneous injections or oral supplements. Depending on your preference, and your pets, either option can be discussed. Injections can be demonstrated by your wonderful, friendly, neighborhood veterinary technicians.
At this time, dosing instructions will be given based on your veterinarian recommendations, but usually start out with once weekly for a few weeks, then reduce to once monthly. Cobalamin levels should be rechecked prior to reducing your pet’s dosing. Be sure to communicate with your veterinarian or technician about changes you may be seeing with your pet, or concerns about medicating your pet, so they can best advise you throughout your pet’s care.