The Importance of Sodium in a Dog’s Diet: Why It Matters More Than You Think
Sodium is one of those nutrients that often gets a bad rap—especially in human nutrition. We’re bombarded with messages about lowering salt for our heart health, so it’s no surprise that many dog owners question how much sodium their dog really needs.
But here’s the reality: sodium is an essential nutrient for dogs. It plays a crucial role in maintaining fluid balance, nerve function, and muscle health. However, just like with any nutrient, balance is key. Too little sodium can be just as harmful as too much.
In this blog, we’ll explore:
Why sodium matters for dogs
The signs of sodium deficiency or excess
How much sodium your dog actually needs
How health conditions like heart disease or kidney issues affect sodium needs
The science behind sodium in canine nutrition
How to evaluate your dog’s diet for optimal sodium levels
Why Is Sodium Important for Dogs?
Sodium (Na) is a macromineral—a type of mineral required in relatively large amounts in the diet. It works alongside chloride (Cl) and potassium (K) to maintain:
Fluid balance and hydration status
Osmotic pressure between cells
Muscle function (including the heart)
Nerve signal transmission
Acid–base balance in the blood
According to the National Research Council (NRC, 2006) and FEDIAF (2023) guidelines, sodium is essential in a dog's daily diet, and its absence or excess can quickly lead to health complications.
Sodium is absorbed in the small intestine and is tightly regulated by the kidneys and hormones such as aldosterone. It is not stored long-term in the body, which is why dietary intake must be consistent and adequate.
The Roles of Sodium in the Canine Body
Here’s a breakdown of how sodium supports critical physiological functions:
1. Fluid Balance & Hydration
Sodium helps regulate how much water is inside and outside your dog’s cells. It ensures your dog maintains blood pressure and circulation. Without enough sodium, your dog could quickly become dehydrated—even if they’re drinking water.
2. Muscle and Heart Function
Sodium is essential for muscle contractions. The heart is a muscle too, so sodium plays a role in regulating your dog’s heartbeat and cardiac rhythm. It also partners with potassium to ensure proper muscle signaling and coordination.
3. Nerve Impulse Transmission
Every time your dog moves, reacts to stimuli, or wags their tail, sodium is at work. It enables electrical impulses between nerve cells, making it critical for cognition and movement.
4. Nutrient Transport
Sodium acts as a co-transporter for nutrients like glucose and amino acids into cells. Without it, your dog may struggle to get energy from their food.
How Much Sodium Does a Dog Need?
Both AAFCO and FEDIAF provide minimum recommended sodium intakes for adult dogs:
Bodyweight (kg)Minimum Sodium (mg/day)
5 kg 100mg
10 kg 200mg
20 kg 400mg
30 kg 600mg
FEDIAF’s recommended sodium level for adult maintenance is:
0.2% on a dry matter basis (DMB)
AAFCO’s recommendation for adult dogs is:
0.08% as-fed minimum sodium
However, these levels can vary based on activity level, age, health status, and environmental conditions (e.g., hot climates where dogs sweat more through panting).
What Happens If a Dog Gets Too Little Sodium?
Sodium deficiency, or hyponatremia, can occur if a dog is:
Fed a homemade diet that isn’t balanced
Drinking excessive amounts of water (polydipsia)
Suffering from chronic diarrhoea, vomiting, or renal disease
Treated with diuretics or has Addison’s disease
Symptoms of Sodium Deficiency in Dogs:
Weakness or lethargy
Confusion or disorientation
Vomiting or diarrhoea
Low blood pressure
Seizures (in severe cases)
Collapse
Study Highlight:
A study by Feldman et al. (2005) found that dogs with hypoadrenocorticism (Addison’s disease) often presented with hyponatremia, and correction of sodium balance was critical to recovery and survival.
What Happens If a Dog Gets Too Much Sodium?
Excess sodium, or hypernatremia, is less common but still a concern. It typically arises from:
Salt poisoning (eating salt-heavy foods like ham, chips, or sea water)
Inadequate access to water
Underlying disease, such as diabetes insipidus or severe dehydration
Symptoms of Excess Sodium:
Excessive thirst (polydipsia)
Increased urination (polyuria)
Disorientation
Tremors or seizures
Vomiting
Coma or death (in severe salt poisoning)
Case Study:
A 2011 review in Veterinary and Human Toxicology reported multiple cases of dogs ingesting salt dough from holiday crafts, resulting in severe hypernatremia, neurological symptoms, and fatalities.
Sodium and Specific Health Conditions
1. Heart Disease
Traditionally, dogs with heart failure were placed on low sodium diets to reduce fluid retention. However, more recent research shows that moderate sodium restriction is more appropriate and aggressive sodium restriction may not improve outcomes.
Study: Freeman et al. (2013) published in Journal of Veterinary Internal Medicine found that severe sodium restriction may activate the renin-angiotensin-aldosterone system (RAAS) and worsen clinical signs.
For dogs with early-stage heart disease, a normal or slightly reduced sodium intake is often suitable. In advanced stages, therapeutic diets with controlled sodium are advised—under veterinary supervision.
2. Kidney Disease
Sodium control is also a component of renal diets, but again, excessive restriction may not be beneficial. Dogs with CKD often suffer from dehydration and electrolyte imbalances, and sodium may help maintain hydration and renal perfusion.
Study: Polzin (2011) notes that moderate sodium restriction in dogs with CKD may help lower blood pressure but must be balanced against risks of hyponatremia and decreased palatability of the diet.
3. Endocrine Disorders (e.g., Addison’s Disease)
Dogs with Addison’s disease often require increased sodium intake due to their impaired ability to retain salt.
Sodium in Commercial and Homemade Diets
Commercial Diets
Most complete and balanced commercial dog foods (kibble, wet, raw, cold-pressed) meet sodium requirements. However, some processed foods, especially treats, jerky, or table scraps, can be excessively high in sodium—especially those preserved with salt.
Always check:
The guaranteed analysis
Ingredient list for salt, sodium chloride, or preservatives
Whether the food is FEDIAF or AAFCO compliant
Homemade Diets
Homemade or raw diets are a common cause of sodium deficiency if not professionally formulated. Muscle meats are relatively low in sodium, and dogs require added salt or sodium-containing ingredients to meet FEDIAF standards.
Sodium Sources You Can Add Safely:
Iodised table salt/Himalayan salt (in small, measured amounts)
Kelp (dual iodine and sodium source)
Sodium chloride supplements
Bone broth (only if unsalted)
If you are home cooking for your dog, consult a canine nutritionist to ensure the recipe includes adequate but not excessive sodium.
References and Studies
Axelsson, E. et al. (2013). The genomic signature of dog domestication reveals adaptation to a starch-rich diet. Nature, 495, 360–364. https://doi.org/10.1038/nature11837
NRC (2006). Nutrient Requirements of Dogs and Cats. National Academies Press.
FEDIAF (2023). Nutritional Guidelines for Complete and Complementary Pet Food for Cats and Dogs.
Feldman, E. C., Nelson, R. W. (2005). Canine and Feline Endocrinology and Reproduction. Saunders.
Freeman, L. M., Rush, J. E. (2013). Nutrition in cardiac disease. Journal of Veterinary Internal Medicine, 27(6), 1332–1344. https://doi.org/10.1111/jvim.12135
Polzin, D. J. (2011). Chronic kidney disease in small animals. Veterinary Clinics of North America: Small Animal Practice, 41(1), 15–30.
Gwaltney-Brant, S. M. (2012). Toxicology of sodium in animals. In Veterinary Toxicology, 2nd ed., Academic Press.
Final Thoughts: Should You Worry About Sodium?
For most healthy dogs, sodium is not something to fear—but something to monitor. It’s a vital nutrient that deserves attention, especially if your dog is eating a homemade diet, has a medical condition, or is on long-term medication.
If you’re unsure whether your dog’s diet contains the right sodium levels, or you’re considering a home-prepared diet, get professional guidance.
The Canine Dietitian offers one-on-one consults and tailored nutrition plans to support dogs and their owners Join The Canine Code for exclusive recipes, gut health tips, and supplement guidance tailored to your dog.
If you need personalised advice regarding your dog’s diet or health, feel free to reach out to The Canine Dietitian at www.thecaninedietitian.co.uk. Or click here for a FREE diet assessment. We’re here to help ensure your dog gets the best nutrition possible!