Is Zinc Deficiency causing your Dog's Behaviour Problems?

Zinc and Behaviour: The Overlooked Link in Dog Nutrition

What inspired this blog post was a TikTok I came across recently featuring a dog named Sunoco, shared by trainer Sara (@bdtsara) whose behaviour problems were linked to malnutrition, specifically a zinc deficiency. This got me to revisit a three-part case study series from Sarah Stremming’s Cog-Dog Radio podcast (May 2022), which followed Keen, a dog whose behavioural issues were eventually linked to zinc deficiency.

Between the myths circulating on social media and the thoughtful case discussion in the podcast, I felt it was important to dig into what the science really says about zinc and behaviour in dogs.

Clearing Up the Myths About Zinc Deficiency

Some people in the comments on social media are suggesting that neutering and vaccinations cause zinc deficiency. Just as vaccines do not cause autism, they also do not cause a zinc deficiency. There is no evidence that spaying or neutering alters zinc absorption, metabolism, or requirements.

The real causes of zinc deficiency in dogs are:

Genetics: Some breeds, especially Huskies and Malamutes, have a hereditary condition (zinc-responsive dermatosis Type I) that prevents them from absorbing enough zinc even when the diet is adequate.

Dietary inadequacy: A major and preventable cause. Diets that do not meet AAFCO standards, including many raw or home-prepared diets not formulated by a board-certified veterinary nutritionist, are often deficient in zinc and other micronutrients. Simply adding vegetables or “superfoods” like carrots, blueberries, or kale to a meat-based diet does not make it balanced.

Nutrient interactions: Diets high in phytates from grains, legumes, or cruciferous vegetables bind zinc and block absorption. Excess copper from too much liver, calcium, or iron can also interfere with zinc uptake.

Medical conditions: Chronic gastrointestinal disease, chronic kidney disease, or rapid growth in puppies can all increase the risk of deficiency.

These are the true risk factors. Neither neutering nor vaccinating are risk factors.

Why Zinc Matters

Zinc is essential for more than 300 enzymatic reactions in the body. In the brain, it modulates neurotransmitters, supports synaptic plasticity, and helps regulate stress. In the immune system, zinc controls inflammation and supports repair. When zinc is lacking, dogs may develop lethargy, depression, irritability, anxiety, poor learning, social withdrawal, or changes in skin and coat.

What the Science Says

Animal models of zinc deficiency: A 2015 review by Hagmeyer and colleagues showed that prenatal zinc deficiency leads to lasting deficits in memory, social behaviour, and stress regulation, at least in the mouse model. In adult animals, dietary deficiency causes anxiety, aggression, and depression-like behaviours. These findings closely parallel what we see in human mental health conditions associated with zinc deficiency.

Clinical evidence in dogs: A 2016 study of terriers with behaviour issues found they had significantly lower serum zinc and lower total antioxidant capacity compared to matched controls. Copper and iron levels did not differ between the case and the control dogs, highlighting zinc itself as the key factor.

Variability in dog foods: A 2021 review by Pereira and colleagues reported that zinc content in commercial dog foods is highly variable. Some diets fail to meet minimum requirements, while others exceed safe upper limits. Organic forms of zinc are generally more bioavailable than inorganic ones, particularly when dietary supply is marginal.

Supplementation studies: A pilot study testing the combination of omega-3 fatty acids, magnesium, and zinc in dogs with behaviour problems found significant reductions in fearfulness, destructiveness, and inappropriate elimination. While it did not show a reduction in aggression, it does suggest that carefully balanced supplementation can support behavioural improvement.

Case Spotlight: Keen’s Story

On Cog-Dog Radio, trainer Sarah Stremming shared the story of Keen circa May 2022. Despite excellent training, enrichment, and a dedicated guardian, Keen continued to struggle with behaviour problems. Veterinary testing revealed he was zinc deficient. With targeted, veterinary-guided zinc supplementation, his behaviour improved significantly.

Sarah is clear: zinc deficiency is rare, and not every reactive or anxious dog has a nutritional imbalance. But Keen’s case illustrates why nutrition must always be considered in a thorough behaviour plan.

This was the key point for Sunoco’s owner (also a Sara) to get him tested for micronutrients. Missing in her TikTok post was whether Sunoco was being fed a balanced diet.

The Phytate Problem

Phytic acid, prevalent in many plant-based foods like legumes, whole grains, nuts, and seeds, can dramatically reduce mineral absorption, including zinc. This occurs when those phytates bind zinc in the gastrointestinal tract and prevent absorption. So, BARF (whole food, uncooked, unprocessed) if they are high in seeds or food such as kale, these can prevent zinc absorption. While these foods may seem nutritious, their phytate content can counteract the benefits, especially in diets not balanced with highly bioavailable zinc sources. On the brighter side, most meats and organ meats contain no phytates, and certain vegetables like broccoli and celery have minimal amounts. If you’re preparing home-cooked meals containing grains or legumes, you can soak, germinate, ferment, or cook these food items to help reduce phytate levels, but this does NOT eliminate the need for balance and supplement the diets.

Organ Meats: More Than Just Liver

Liver is rich in many nutrients but extremely high in copper, which can reduce zinc absorption and contribute to copper storage disease in susceptible breeds. To maintain mineral balance, rotate through other organ meats such as kidney, heart, tongue, and spleen. These are good sources of zinc, iron, taurine, and B vitamins without the copper overload of liver.

Many veterinary clinics have a treat jar full of liver treats! This is where I like to substitute complete and balanced freeze-dried diets in place of freeze-dried liver so that I don’t have to limit the number of treats my patients get for training.

Recommendations for Pet Guardians

Behaviour is whole-body health. Here are my key recommendations:

• Zinc is essential: It supports brain development, emotional stability, learning, and immune health every day.

• Assess the diet: Ensure your dog’s food is complete and balanced according to AAFCO standards. If zinc is not listed, request a nutrient analysis.

• Watch for absorption issues: Phytates, excess copper, calcium, or iron, and the form of zinc (organic versus inorganic) all affect bioavailability.

• Use organ diversity: Rotate kidney, heart, tongue, and spleen in addition to liver.

• Supplement thoughtfully: Omega-3 fatty acids, magnesium, and zinc may help with certain behaviour issues, but do so only under veterinary guidance.

• Start with a full assessment: Every behaviour case should begin with a physical exam and nutritional review, not just training alone.

• Work with your veterinarian: Do not just use human zinc supplements for your dog. Veterinary guidance is critical to maintain the correct zinc to copper balance. If you dog has a medical condition, consider using a board-certified veterinary nutritionist to balance your dog’s diet.

Final Thoughts

Zinc deficiency is uncommon, but it is a critical piece of the behaviour puzzle when it does occur. Nutrition and behaviour are inseparable: the brain is part of the body, and both must be cared for together.

Do not be swayed by marketing terms like “BARF” or “whole food.” Do not assume that adding vegetables or “superfoods” to meat makes a diet balanced. Raw diets are not the answer to behaviour problems.

If you want to prepare meals at home, consider a properly balanced home-cooked diet using evidence-based tools such as Balance It. By ensuring your dog’s diet meets their nutritional needs, you give them the best foundation for both physical and behavioural well-being.

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References:

Hagmeyer, S., Haderspeck, J. C., & Grabrucker, A. M. (2015). Behavioral impairments in animal models for zinc deficiency. Frontiers in behavioral neuroscience, 8, 443. Link

Niyyat, M. R., Azizzadeh, M., & Khoshnegah, J. (2018). Effect of supplementation with omega-3 fatty acids, magnesium, and zinc on canine behavioral disorders: Results of a pilot study. Topics in companion animal medicine, 33(4), 150-155. Link

Pereira, A. M., Maia, M. R., Fonseca, A. J. M., & Cabrita, A. R. J. (2021). Zinc in dog nutrition, health and disease: a review. Animals, 11(4), 978. Link

Soltanian, A., Khoshnegah, J., & Heidarpour, M. (2016). Comparison of serum trace elements and antioxidant levels in terrier dogs with or without behavior problems. Applied Animal Behaviour Science, 180, 87-92. Link