Sodium in Dogs – Level, Deficiency and Sodium Poisoning

Sodium (Na) is a vital dietary element required by canines for proper body functions. It is the major positively charged (cation) in the extracellular fluids of animals and human beings found mainly in interstitial fluids and blood plasma.


Some of its primary functions of sodium in dogs include:

  • Controlling blood pressure and blood volume.
  • It helps in maintaining the normal osmotic balance between intracellular and extracellular fluids as well as water levels in body fluids balance to avoid swelling or cell crenation.
  • It helps maintain electrolyte balance and aids in nerve impulse transfer as well as heart, brain, and muscle function.
  • Has a role in pH balancing

While salt (sodium chloride or NaCl) helps improve food palpability in omnivores and herbivores, it doesn’t seem to have the same effect in canines. These pets don’t show salt preference or appetite for it. 

Lack of preference for salty foods is evidence that these carnivores get enough of this mineral in their prey.


Some of the natural food sources of sodium include poultry, meat, chicken, and eggs. However, to meet the required amounts (nutritional adequacy), manufacturers add table salt, sodium tripolyphosphate, and sodium nitrite to dog foods.

Sodium in Dogs - Sodium chloride (NaCl)

Requirements by dogs?

The exact amount of sodium required by dogs depends on their size, activity level, age, water consumption, health status, reproduction, among other factors.

The Association of American Feed Control Officials (AAFCO) has a minimum requirement of 0.3% for growth and reproduction, while for adult maintenance, the amount is 0.08% on dry matter basis.

Based on calorie content, AAFCO has a minimum of 0.80g for growth and reproduction per 1000 kcal metabolizable energy (ME) while for adult maintenance, the amount is 0.20g for “maintenance of body weight at an average caloric intake for dogs of a given optimum weight.”

The European Pet Food Industry (FEDIAF) has the Nutritional Guidelines for Complete and Complementary Pet Food for Cats and Dogs that give guidelines.

Finally, if you use homemade based diets, let your vet guide you on amounts of salt to add as several factors affect its intake or requirement.

Sodium balance in canines

Healthy dogs and other animals can maintain sodium ion (Na+) concentration in their body within a guarded maximum and minimum levels. Excessive or too little will be detrimental to their health, with extreme ends being fatal. 

Dietary sodium sources, including salt absorption, occurs in the ileum and excess amount and excess eliminated via kidney with a smaller amount lost via feces and sweat. Its absorption is very efficient since it has high digestibility. However, cellulose, soy-derived protein, and carbs that are poor to digest may reduce absorption efficiency.

How do dogs keep Na+ balance? The answer is simple. When a dog’s diet is high in this sodium, its blood plasma concentration goes high. The body will detect a rise and initiate a corrective measure to restore normal levels through:

  1. Excreting more Na+ in the kidney and expelling it via urine while retaining more water. This urine concentration process will help bring its concentration in the blood plasma.
  2. Stimulating thirst to encourage these animals to take more water to help in the sodium excretion in the kidney.

On the other hand, if your dog has low Na+ concentration in their blood, such as when on sodium deficiency or restricted diets or due to any other cause, their kidney will retain most of the Na+ by allowing very little or none lost via urine. This corrective measure will help maintain its level in blood.

Deficiency – low sodium in dogs

A reason why AAFCO sets a minimum amount of sodium in dog diets is to prevent deficiencies from happenings as they can result in hyponatremia. It happens when blood sodium ion levels go belwo140mE/L (mmol/L). The normal range should be 140-149 mE/L (mmol/L).

Typical symptoms include lack of energy, vomiting, nausea, reduced appetite as well as neurological signs like reduced alertness, disorientation, confusion, muscle weakness, seizures, and coma. In extreme cases, your Fido will die.

In most instances, dietary deficiency isn’t the cause of hyponatremia. However,  it is possible to be a cause. Frequent causes of hyponatremia include excessive fluid through diarrhea, vomiting, and so on, where this mineral is lost. Also, excessive urination, antidiuretic mediation, quick intravenous fluids, as well as some disease and conditions can be a cause.

We have a piece exclusively on low sodium in dogs, which will give you all causes, symptoms, diagnosis, and living management.

High sodium in dogs

As you try to avoid a deficiency in your dogs, don’t forget that excessive amounts in their blood plasma will lead to sodium poisoning or toxicity (hypernatremia). It happens when Na+ concentration goes beyond 150 mE/L (mmol/L) in a dog’s blood plasma.

There are three types of hypernatremia, i.e., hypovolemic, euvolemic or hypervolemic hypernatremia whose common causes being pet not drinking water, salt poisoning (pet ingesting a lot of salt ), high sodium intravenous injections, some diabetes forms, and so on.

We have details on sodium or salt toxicity in dogs with more information that includes causes, symptoms, diagnosis, treatment, and living management.

Best low sodium dog foods

Dogs already suffering from heart, kidney, and heart disease, need diets with limited sodium amounts (not below AAFCO’s).  Some good brands to try include:

See more on best low sodium dog foods for reviews and more details.

Is salt bad for dogs?

No. Salt isn’t bad for dogs. It is one of the best sources of sodium, which has many vital roles, as we have seen.

Furthermore, it is a good source of chloride, which is the most crucial electrolyte in the body that helps maintain proper blood volume and pressure, body fluid pH, inside and outside cell fluid balance, among other roles.

However, excessive amounts or too little amount is harmful to pets. Also, some conditions like liver, heart, or kidney disease may warrant sodium-restricted diets.

See also

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