Treatment for vitamin B12 deficiency in dogs

Deficiency of vitamin B12, or cobalamin, is uncommon in dogs and most often occurs secondary to chronic gastrointestinal disease. GI conditions, such as chronic pancreatitis, exocrine pancreatic insufficiency, and inflammatory bowel disease, can result in a decreased ability to absorb B12 in the GI tract, leading to a deficiency despite the dog eating a balanced diet. If you have a dog, read on to learn about:

• How B12 plays a crucial role in a dog’s health
• Conditions that can lead to a B12 deficiency
• How B12 deficiencies are diagnosed and treated in dogs
• Dogs at risk for a B12 deficiency

Diagnosing and treating a dog with a B12 deficiency starts with identifying not just the deficiency itself but also the underlying health issue causing it. Because symptoms are often vague, a diagnosis cannot be made based on signs alone. Effective treatment includes addressing the root cause and providing vitamin B12 supplementation as recommended by a veterinarian.

Vitamin B12 is an essential nutrient, meaning a dog isn’t able to produce the nutrient and instead must ingest it in their diet. B12 plays a vital role in many body functions, including:

• Red blood cell production
• DNA production
• Nervous system operation
• Amino acid metabolism

When something is causing a limited ability to properly absorb B12 (cobalamin) from food or, less commonly, if a dog is not ingesting enough B12, the body uses B12 stores to compensate. Dogs become cobalamin deficient as these cobalamin stores are depleted.

“Low levels of B12 in dogs are a sign that something is wrong,” explains Dr. Jo Myers, a veterinarian on the Vetster platform. “A B12 vitamin deficiency usually indicates a health issue that’s affecting the digestive tract’s ability to work properly.” In rare cases, a B12 deficiency may be caused by a hereditary condition or an inadequate amount of B12 in the diet. Low levels of cobalamin are an indicator not only that a dog may have a gastrointestinal disease but also of how severe that disease is.

Understanding the underlying cause of a B12 deficiency is essential for effective diagnosis and treatment. The majority of cases of cobalamin deficiency are caused by a gastrointestinal issue that affects cobalamin absorption, even if the dog’s diet is well balanced and they’re ingesting sufficient B12.

Less commonly, conditions like liver dysfunction or chronic kidney disease may also directly contribute to low B12 levels. Medical conditions that can lead to a B12 deficiency include:

• Inflammatory bowel disease (IBD)
• Lymphoma
• Exocrine pancreatic insufficiency (EPI)
• Small intestinal bacterial overgrowth (SIBO)
• Chronic pancreatitis
• Protein-losing enteropathy (PLE)
• Gastrointestinal worms
• Liver disease
• Kidney disease
• Gastrointestinal cancer

Hereditary cobalamin deficiency and low levels of dietary cobalamin are rare causes of cobalamin deficiency.

Vitamin B12 deficiencies are rare in dogs eating a commercially prepared, balanced diet that meets AAFCO nutritional guidelines. However, homemade diets or unconventional diets, including vegan or vegetarian diets, may carry a higher risk of deficiency if they’re not properly formulated. Because B12 is naturally found only in animal-based ingredients, plant-based diets must include synthetic supplementation to meet a dog’s nutritional needs. This makes these diets more challenging to formulate correctly without guidance from a veterinary nutritionist.

Some breeds may carry a gene for hereditary cobalamin deficiency, but the specific gene has not been identified.

Clinical signs of cobalamin deficiency in dogs

Symptoms from the underlying gastrointestinal disease are usually much more obvious than symptoms associated with B12 deficiency. Clinical signs of cobalamin deficiency in dogs are often vague and difficult to attribute to anything specific. Symptoms include:

• Lethargy
• Loss of appetite
• Weight loss
• Weakness
• Stunted growth in puppies
• Failure to thrive in newborn puppies

Severe cobalamin deficiency can also result in neurologic symptoms, such as seizures and ataxia.

The diagnostic process starts with a veterinarian taking a full history and assessing the patient, including getting a full understanding of any symptoms they are showing. Symptoms of B12 deficiency in dogs are often vague and nondescript. The main symptoms a dog has are usually the result of the underlying gastrointestinal disease that’s causing the deficiency, such as vomiting, diarrhea, or weight loss. These symptoms are shared by many other, more common illnesses, so an accurate diagnosis is necessary in order to know what kind of treatment the dog needs.

In addition to a complete history and examination, a full workup is often needed to diagnose the primary disease, which may include:

• Physical examination
• Diagnostic imaging
• Blood work
• Urinalysis
• Fecal testing
• Intestinal biopsy

Once the underlying illness is diagnosed, identifying a B12 deficiency is fairly straightforward using a simple blood test.

Treatment options are targeted to the underlying disease that led to the B12 deficiency, which may include infections, pancreatic diseases, digestive disorders, and others. Depending on the case, treatment may include:

• Antibiotics
• Dietary therapy
• Supplementation of pancreatic enzymes
• Anti-inflammatories
• Nausea and pain medication
• IV fluid therapy
• Surgery

Oral cobalamin supplementation may be recommended while the underlying cause of the deficiency is being treated. In cases of hereditary B12 deficiency, the patient may need lifelong vitamin supplements. In the rare case of inadequate amounts of B12 in the diet, a diet change may be recommended. The prognosis varies depending on the underlying cause of the deficiency and how severe the deficiency is.

It’s essential to work with a veterinarian to identify the underlying cause before starting treatment. Simply changing your dog’s diet or giving a supplement without guidance may not help and could even delay proper care. Early intervention for GI conditions not only supports B12 levels but also helps prevent a range of additional health problems.

Dogs at risk for B12 deficiency

Some dogs are more at risk for a B12 deficiency than others. Risk factors include dogs with:

• Chronic GI upset or disorders
• Kidney or liver disease
• Cancer

Talk to a veterinarian if you’re concerned about your dog’s B12 levels or whether your dog is eating a complete and healthy diet. An online vet is available to discuss your furry friend’s diet, assess their overall risk for a B12 deficiency, and help determine the most appropriate next steps.

What are the symptoms of B12 deficiency in dogs?

Symptoms of a vitamin B12 deficiency in dogs are vague, nonspecific, and may be very subtle unless the deficiency is severe. Signs of a B12 deficiency include mental dullness, lethargy, loss of body weight, and appetite loss. With severe deficiencies, dogs may develop neurologic issues, such as seizures. Because a B12 deficiency is most often caused by chronic GI diseases, symptoms caused by that issue are usually identified before the B12 deficiency itself.

How can I increase my dog’s vitamin B12 levels?

The first step is identifying why your dog’s B12 levels are low and addressing that. Healthy dogs are highly unlikely to develop a B12 deficiency, so it’s unlikely that changing your dog’s food or giving B12 supplements can provide a complete solution. If a dog is deficient in vitamin B12, the underlying cause of the deficiency, usually a gastrointestinal disease such as pancreatic disease or inflammatory bowel syndrome, needs to be appropriately treated in order to treat the B12 deficiency. Supplementation and diet changes are best done under the guidance of a veterinarian and tailored to the individual dog's needs based on the underlying reason for the deficiency.

What should you feed a dog with a B12 deficiency?

The most important part of managing a B12 deficiency is treating the underlying condition that’s preventing proper absorption rather than focusing solely on diet. While dogs with a B12 deficiency often have an intestinal disorder affecting absorption, a diet change is not always necessary. However, it may be recommended in specific cases, such as with food allergies, dietary-responsive inflammatory bowel disease, or exocrine pancreatic insufficiency. In many cases, B12 supplementation is used alongside treatment for the underlying issue without requiring a change in diet.

Disclaimer: This article, its content, and its related references do not constitute veterinary advice and should not be considered a substitute for veterinary care. If your pet is showing any symptoms that could indicate a medical emergency, please seek immediate emergency care.