Salt and your dog: Is it as bad as they say?

In general, salt has a pretty bad reputation as a food ingredient or seasoning. For humans, high levels of dietary salt can and often does lead to health problems like high blood pressure.

Many people tend to assume that what is true for humans also applies to our dogs. That like humans, too much salt in a dog’s diet is a bad thing and will cause the same health problems as it does in humans.

This isn’t always the case. While similar in some ways, humans and dogs are different, and the effects of dietary salt on human health may not apply to our dogs.

Let’s take a look at what’s true and what’s false when it comes to salt in your dog’s diet.

Dogs need salt in their diet: TRUE    
To stay healthy, your dog requires a certain amount of salt in their diet. When it is ingested and subsequently dissolves in the blood, it plays an important role in many of your dog’s daily bodily functions.

For example, salt helps to regulate your dog’s heartbeat as well as nerve function. It’s also involved in maintaining blood pressure and pH levels, and it is involved in hydration – regulating water balance, urinary concentration, and thirst signals.

Without salt, your dog’s body could not function properly.

Adding salt to your dog’s food increase palatability: FALSE
You may have read that pet food manufacturers add salt to their foods as a flavour enhancer to increase the foods palatability. But this is simply not true.

For humans, salt brings out the flavour of a dish. This is because some flavour compounds are too subtle to detect, but when you add a small amount of salt, neurological magic happens and suddenly, our taste receptors can detect flavours they weren’t able to sense before.

For dogs, it doesn’t quite work that way. A dog’s sense of taste is different to us humans, and studies have shown that they don’t have a preference for foods with high levels of salt. In fact, some studies have shown that increased levels of salt puts them off.

How much salt dogs need depends on the dog: TRUE
How much salt a dog needs to stay healthy depends on many factors such as breed, size, weight, and age of the dog.

The minimum requirements of salt for healthy adult dogs in commercial diets is 0.06% DM (AAFCO, 2007). Current AAFCO regulations have no established maximum for salt in dog food and many commercially available dog foods exceed the minimum salt requirements by 4 to 15-fold but

The Nutritional Research Council (NRC, 2006) have an equation to calculate recommended allowances for dogs fed a home-prepared diet. That equation is:

kg BW^0.75 x 26.2 mg (kg BW = body weight in kilograms)

The NRC currently defines a safe upper limit for salt of 15g/kg dry matter.

High dietary salt will cause health problems in dogs: FALSE
In humans, persistent, high levels of dietary salt can result in health problems, including but not limited to high blood pressure, kidney problems and heart disease.

The same is not true for dogs.

Healthy adult dogs can adapt well to – and are very tolerant of – fluctuations in salt levels. They can handle salt at high levels and still maintain a healthy, constant level of blood pressure and blood salt concentrations. A salt toxicity is only seen at levels above the NRC safe upper limits.

Salt restriction is recommended for dogs with heart disease: TRUE
Although there are limited data on the clinical benefits of salt restriction for dogs with heart failure, low sodium diets have been associated with reductions in heart size and improvements in cardiac function. Because of this, many vets will suggest a lowering or restriction of salt in the diet of dogs with heart failure.

The important thing to note here is that it’s a lowering – not omitting – of salt in the diet. And it’s not needed in all dogs. If your dog has heart problems, before making any dramatic changes to their salt intake, it’s best to speak to your vet.

Salt is an essential part of any healthy dog’s diet. The definitive level of salt that any dog requires depends on the dog, but in general, dogs can tolerate high levels of salt and fluctuations in the levels. In fact, any excess salt that your dog consumes and doesn’t require is excreted in their urine.

High levels of salt in the diet can cause your dog to become thirstier and drink more water, but for most dogs, that’s the extent of the problems it can cause. For dogs with existing heart conditions, it is more important to keep an eye on salt levels, so they don’t exacerbate the condition.

If you feel your dog may be consuming too much – or indeed too little – salt in their diet, as always, the best thing to do is to speak to your vet.

Further reading