Sodium

Sodium is an essential mineral that regulates fluid balance, nerve function and blood pressure in dogs.

As an electrolyte, sodium controls water distribution between body cells and enables signal transmission in nerves and muscles. The sodium level in the blood must remain within a narrow range – both deficiency and excess lead to serious health problems.

How much sodium does a dog need daily?

The sodium requirement does not depend on body weight, but on the energy content of the food. The European Pet Food Industry Federation (FEDIAF) states 0.25 to 0.29 grams of sodium per 1000 kilocalories for adult dogs. The two values represent two assumptions regarding energy requirements. A 20-kilogram dog eats around 1000 kilocalories a day and therefore needs just over a quarter of a gram of sodium, not several grams. As proven sufficient, the same guideline even specifies only 0.19 grams per 1000 kilocalories; the table values include a safety margin.

Complete diets reliably cover this amount, so a sodium deficiency from commercially available complete food is not a realistic scenario. The sodium content is listed in the analytical composition on the packaging. According to FEDIAF, levels of up to 1.5 per cent of dry matter are safe, but explicitly only for healthy dogs: In cases of heart or kidney disease, the vet determines the amount of sodium.

Puppies and lactating bitches need more. FEDIAF specifies 0.55 grams per 1000 kilocalories for growth and reproduction, roughly double the value for adult dogs. In nursing bitches, it is also worth noting that they naturally eat several times their normal amount of food, so the daily intake increases even more significantly.

How do I recognise a sodium deficiency in my dog?

Sodium deficiency (hyponatraemia) is usually caused by significant fluid loss – for example, after persistent vomiting, diarrhoea or excessive drinking.

The first signs are weakness and an unsteady gait. The dog appears dazed and reacts slowly when spoken to. As the deficiency progresses, muscle cramps and trembling may occur. In severe cases, seizures can develop.

The insidious aspect is that the symptoms develop gradually and are often not recognised until late. A dog with a sodium deficiency may appear normal in the morning but struggle to stand by evening.

What happens when there is too much sodium in a dog’s body?

Sodium excess (hypernatraemia) occurs when dogs eat salty human food or suffer from severe dehydration. The body tries to dilute the excess salt – hence the first sign: extreme thirst.

A dog with hypernatraemia drinks unusually large amounts of water but still appears restless and disoriented. Breathing may become rapid. Without treatment, this condition leads to unconsciousness.

Typical triggers include chips, salted snacks or leftovers from human meals. Signs of poisoning can occur at doses of 2 to 3 grams of table salt per kilogram of body weight; the lethal dose for dogs is approximately 4 grams per kilogram.

Which food sources contain natural sodium?

Meat is the main source of sodium for dogs. Beef contains approximately 70 milligrams of sodium per 100 grams, while chicken contains slightly less. Fish – particularly sea fish – has higher levels.

Eggs provide moderate amounts of sodium and are easily digestible. Offal such as liver or kidneys have higher sodium content but should only be fed occasionally due to their intensity.

Cereals and vegetables naturally contain little sodium. Vegetarian dog food therefore often needs to be enriched with sodium chloride.

When does a dog need additional sodium?

Additional sodium is only necessary in exceptional cases. Working dogs that exert themselves heavily in high temperatures can lose electrolytes through sweating. In such cases, an electrolyte solution may be beneficial.

In kidney disease, sodium regulation is impaired. Some dogs then require low-sodium food, while others need controlled sodium supplementation. The vet always makes this decision based on blood test results.

After severe diarrhoea or vomiting, the electrolyte balance can become disrupted. Correction is usually achieved through infusions rather than food supplements.