What is Chloride?
Chloride, simply put, is chlorine when chlorine gains an electron. Chlorine on its own at room temperature is a diatomic element that exists as a highly corrosive gas. However, because chlorine only needs one electron to complete its octet, it desperately desires to take an electron. Therefore, chlorine bonds with other elements such as sodium or potassium (who wish to lose an electron) to form a polyatomic ion. When chlorine gains an electron, it becomes chloride and has a negative charge.
Chloride is an electrolyte that works with sodium in extracellular fluid. It is needed for numerous functions including nutrient absorption and transport, nerve impulses, component of digestive fluid, maintenance of blood volume, pH, and pressure.
But details schmetails, let’s talk about how we can make sure chloride is present in a raw diet.
Where Is Chloride Found?
As explained above, -ide indicates an anion. Because chlorine on its own is rather unstable, it is naturally found charged with a cation. The most common cations being sodium and in other instances potassium (there are others, too). For example, salt is NaCl, or sodium chloride. In a solution, these ions dissociate but are still present.
Rather than Keeping Up With The Kardashians, elements would rather keep up with the noble gasses as they flaunt their non-reactive, beautiful octets (think of the number eight) around town. Enter chlorine. Chlorine has 7 valence electrons- ever so close to being the perfect octet and joining the class of nobles. Close, but no cigar.
Enter sodium and potassium. These lovely elements are clear across the periodic table and have just 1 valence electron. If they could just find somebody to take that electron off their hands, they too could become like the noble gasses (as the previous subshell is already filled with electrons).
So sodium (or potassium) and chloride ride off into the sunset.
Bottom line? Sodium (or potassium) needs to lose an electron and chlorine would love to take that electron. Their beautiful love child being tasty, tasty salt.
Short In Raw Diets?
While a PMR diet may be short in several nutrients, meat heavy diets are not generally short in sodium or chloride relative to the canine’s requirements. While auditing a PMR diet may yield results indicating low chloride, this is primarily because databases do not provide data for chloride but rather sodium and potassium.
The NRC developed the requirements for chloride directly proportional to the polyatomic ion known as sodium chloride. If you took 100 grams of sodium chloride, approximately 60 grams would be chloride and 40 grams would be sodium. This all checks out because of the weight of sodium and the weight of chloride. The NRC requirements reflect the same proportions. Test it for yourself. A dog weighing 10 kg requires 147 mg of sodium and 224 mg of chloride. 224 + 147 = 371. Chloride making up 60% (224/371) of the combined requirement.
That isn’t to suggest that in food, such as muscle meat, chloride is always found with sodium. As stated above, you can find chloride with other cations. It also isn’t to suggest that we should ignore chloride altogether. We should, however, look at cations in the diet to ensure that we are not ignoring the chloride requirement.
Chloride deficiency is rare and is generally caused by conditions that are the result of overall electrolyte loss (excessive vomiting, dehydration).
Humans, even when considering weight differences, require much more salt than dogs. Without salt, death occurs. Given its importance and how much humans require, it is not surprising that humans will naturally crave salt. This craving has been extremely beneficial because it encouraged humans to seek out salt in order to not die. For reference, a 100 lb adult dog (45.3 kg) will require 455 mg of sodium. A 1 year old child (approximately 20 lb) requires nearly double that. An adult will require, on average, 1,500 mg of sodium.
Using both ancestral wisdom and modern science, it makes sense that dogs can typically acquire enough sodium and chloride without having to salt their food. Audit most meat heavy diets, including only 80% muscle meat and 10% organ (chloride is not present in high amounts in bone), sodium is often well beyond the RA. Even potassium can be met easily. Even though chloride is relatively low in food outside of seaweed and salt, dogs don’t really require high levels.
That being said, table salt (NaCl) can be a valuable addition if the dog’s diet is for whatever reason low in electrolytes and if a lifestage or activity indicates higher requirements. Typically this will mean requirements for other electrolytes are increased as well.
However, given the foundational understanding of basic chemistry, most raw feeders do not need to worry about salting their dog’s food.
It is extremely unlikely that chloride is a nutrient low in most PMR diets fed today.