What are the most common nutritional deficiencies in dogs?
At a glance
- Omega-3 fatty acid deficiency is the most widespread nutritional gap in dogs fed standard dry kibble
- Zinc deficiency causes hair loss, crusty skin, and poor wound healing — certain breeds are genetically prone to it
- Calcium and phosphorus imbalances are common in dogs fed homemade diets without professional guidance
- Vitamin D deficiency weakens bones and suppresses immune function — dogs cannot synthesise enough from sunlight alone
- A diet labelled complete and balanced to FEDIAF standards is the baseline requirement for avoiding deficiencies
What nutritional deficiencies are most common in dogs?
The most common nutritional deficiencies in dogs are omega-3 fatty acids, zinc, vitamin D, calcium, and iron. Most cases are caused by one of two things: a diet built around heavily processed ingredients that have lost key nutrients during manufacture, or an unbalanced homemade diet put together without veterinary nutritional advice. The signs are often subtle at first — a dull coat, flaky skin, low energy, frequent infections — and they tend to worsen gradually rather than appear overnight. Understanding which nutrients dogs are most likely to be short of, and why, is the first step to doing something about it. A good place to start is this complete guide to dog food ingredients and nutrition labels, which explains what a genuinely balanced recipe needs to include.
Which specific deficiencies cause the most visible symptoms?
Omega-3 fatty acid deficiency is the most prevalent issue in dogs on standard kibble diets. Omega-3s — particularly EPA and DHA — are fragile. They degrade quickly during the high-heat extrusion process used to make kibble. The result is a diet that may look complete on paper but consistently underdelivers on these essential fats. The visible signs include a dull, brittle coat, dry or flaky skin, and increased inflammatory conditions like joint stiffness.
Zinc deficiency is the second most common, and it presents dramatically. Dogs with low zinc develop crusty, scaly patches of skin, hair loss around the face and feet, and slow wound healing. Nordic breeds — Siberian Huskies and Alaskan Malamutes in particular — have a genetic tendency to absorb zinc poorly, meaning they need higher dietary levels than most dogs.
Vitamin D sits in a different category because dogs cannot make enough of it through sun exposure, unlike humans. They rely almost entirely on diet. Low vitamin D weakens bones, reduces calcium absorption, and compromises immune function. Deficiency is most common in dogs eating diets with low or degraded animal-source vitamin D.
| Nutrient | Primary signs of deficiency | Most common cause |
|---|---|---|
| Omega-3 (EPA/DHA) | Dull coat, dry skin, joint inflammation | Heat-degraded in processed food |
| Zinc | Crusty skin, hair loss, slow healing | Low dietary levels or poor absorption |
| Vitamin D | Weak bones, poor immunity | Insufficient animal-source vitamin D in diet |
| Calcium | Bone weakness, muscle tremors, fractures | Unbalanced homemade diets |
| Iron | Fatigue, pale gums, poor exercise tolerance | Low meat content, poor bioavailability |
| B vitamins (B1, B12) | Neurological signs, poor appetite, weight loss | Cooking losses, cereal-heavy diets |
Why do homemade diets carry a higher deficiency risk?
Homemade dog food is prepared with good intentions but frequently results in nutritional gaps. A 2019 study published in the Journal of Nutritional Science found that 95% of homemade dog food recipes available online were deficient in at least one essential nutrient. Calcium and phosphorus imbalances are the most dangerous. Dogs need calcium and phosphorus in a ratio of roughly 1.2:1. Too little calcium causes rickets and bone fractures. Too much disrupts kidney function over time.
Iron deficiency follows a similar pattern in homemade diets. Plant-based iron — from vegetables and grains — is non-haem iron, which dogs absorb at roughly 5-15% efficiency. Haem iron from meat is absorbed at 25-35%. A diet heavy in plant ingredients and light on quality meat will consistently deliver less usable iron, regardless of what the total iron figure on the label says. This is why understanding what dog food labels actually mean matters when comparing products.
If you are feeding a homemade diet, a consultation with a board-certified veterinary nutritionist is not optional — it is the only way to know whether your dog is getting everything they need. Persistent symptoms like poor coat condition, low energy, or digestive issues that don't resolve with a diet change always warrant a vet visit.
Does food quality affect how many nutrients a dog actually absorbs?
Yes, significantly. A food can list adequate levels of every essential nutrient on its label and still leave a dog deficient, if those nutrients are in forms the dog cannot absorb well. Bioavailability — how much of a nutrient the body can actually use — varies enormously depending on the ingredient source and how it has been processed.
Fresh animal proteins retain their full amino acid profiles and are more digestible than rendered meat meals, which are cooked at extreme temperatures. B vitamins, in particular B1 (thiamine) and B12, are heat-sensitive and can be significantly reduced by aggressive cooking. Omega-3s, as noted above, are especially vulnerable.
Marleybones' Pantry Fresh meals are freshly prepared and slow-cooked in-pack, which preserves more of the naturally occurring nutrients in the ingredients compared to standard extrusion. The recipes are vet-developed and FEDIAF compliant, meaning they meet the nutritional standards required to call a food complete and balanced for all life stages. Sassy Salmon, for example, provides a natural source of omega-3 EPA and DHA from salmon — one of the highest-bioavailability sources available. Every dog is different — build your personalised Marleybones feeding and health plan tailored to your dog's age, size, and health requirements.
The superfoods included across Marleybones recipes — chia seeds, hemp seeds, and linseeds — add plant-based omega-3 ALA, which supports the overall fatty acid profile of the diet alongside the marine-source EPA and DHA.
“Such a relief to see her enjoying her food”
FAQs
Can I tell if my dog has a nutritional deficiency just by looking at them?
Some deficiencies show clear physical signs. A dull or thinning coat, flaky or crusty skin, pale gums, and low energy are all visible indicators. However, many deficiencies — particularly vitamin D and certain B vitamins — only become apparent through blood tests. If you suspect a deficiency, a vet check and blood panel is the most reliable way to confirm it.
Is it possible for a dog to have too much of a nutrient as well as too little?
Yes. Oversupplementation is a genuine risk, particularly with fat-soluble vitamins like vitamin D and vitamin A, which accumulate in the body rather than being excreted. Excess calcium in large-breed puppies causes skeletal problems. The safest approach is a complete and balanced commercial diet formulated to FEDIAF standards, which sets both minimum and maximum nutrient levels.
Do puppies have different nutritional risks to adult dogs?
Puppies have higher requirements for calcium, phosphorus, DHA, and total protein than adult dogs. Calcium and phosphorus deficiencies in puppies cause developmental bone disease. DHA is critical for brain and eye development in the first months of life. Any food fed to a puppy must be labelled complete for all life stages or specifically for growth — not maintenance only.
Are certain breeds more prone to nutritional deficiencies?
Some breeds have known genetic predispositions. Siberian Huskies and Alaskan Malamutes absorb zinc poorly and need higher dietary zinc. Great Danes and other large breeds are especially sensitive to calcium and phosphorus imbalances during growth. Cocker Spaniels have a higher rate of vitamin B12 malabsorption linked to intestinal issues. Breed-specific risks are worth discussing with your vet when choosing a diet.
Does switching to fresh food reduce the risk of nutritional deficiencies?
Fresh food made to a complete and balanced recipe reduces the risk of deficiencies caused by nutrient loss during high-heat processing. However, not all fresh food is equal. A fresh food diet still needs to meet FEDIAF nutritional standards and be formulated by a qualified nutritionist or vet. Fresh food that has not been properly balanced carries the same risks as a poorly constructed homemade diet.
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