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Low Sodium Kibble – Which Value is Important?

Low Sodium KibbleOver the past few days, I made a few edits to the low phosphorus kibble spreadsheet to add more low sodium kibble values too.

You will notice that on the spreadsheet, each kibble listed has three sodium values – As Fed %, Dry Matter % and mg/100 kcal. Each of these values is significant, but do you know why? Do you know which of these values you should be looking at when you are looking for a low sodium dog kibble?

That’s exactly what I want to talk about today…

Low Sodium Kibble – What You Need to Know About Sodium Values

I’ve written about how to read a dog food label before, but for the sake of being thorough, let me recap what you need to know.

The “As Fed” information on your dog food is the information you will see on the back of a dog food bag. “As Fed” is the nutritional information for a dog food without taking into consideration the moisture content of that food.

For example, Wellness Complete Health Large Breed Adult Deboned Chicken & Brown Rice Recipe has an “As Fed” sodium level of 0.25. This makes it a kibble with moderate sodium restriction. HOWEVER, this kibble contains 11% moisture. What does that mean? It means that when we eliminate the moisture from the kibble we are left with a sodium level of 0.28. This is still a moderately restricted level of sodium, however, it is a higher sodium level than previously thought.

Why Should You Care About Moisture Levels in Kibble?

Moisture Content in Dog Food

Well, different kibble options have different levels of moisture. This means that in order to compare the nutrient levels of a kibble that has 11% moisture content to a kibble that has 8% moisture content, you need a “common denominator”. We find this common denominator by using “dry matter basis”, or by removing moisture from the equation.

Looking at the example above, we have a sodium level of 0.25.

Now, we need to remove the moisture percentage from the food, 100% – 11% = 89%.

So now we take that 0.25 sodium content and divide it by the 89%, 0.25/.89 = 0.28.

This “common denominator” now allows us to compare multiple foods to get an idea of which offers a lower sodium level.

But which level is most important to you when looking for a low sodium kibble?

Dog food companies ALWAYS list “As Fed” information on their packaging. This information is helpful to a certain extent in that it gives you a general idea of the nutrient levels in the kibble. This information is limited in its usefulness, however, if you are looking to compare multiple low sodium kibble options on an even platform.

For example, take a cup of kibble with 11% moisture. 11% of that cup of kibble is made up of water. Now take a cup of kibble with a 8% moisture, only 8% of that cup of kibble is made up of water. Now, assume that both kibble options list a sodium level of 0.25 AS FED. When we remove the moisture content to compare the two kibble options, the first kibble actually has a sodium level of 0.28 and the second actually has a sodium level of 0.27. So, the kibble with a lower moisture content has a lower sodium level.

But What About Low Sodium Kibble mg/100 kcal Levels?

Low Sodium Dog Food

So, now that we have sorted out what the “As Fed” and “Dry Matter” sodium values are…what are the mg/100 kcal levels of sodium and why do they matter?

Sodium mg/100 kcal in Dog Food

Sodium mg/100 kcal tells us how much sodium is in 100 kcal of your dog’s food.

This is important because when veterinarians make sodium recommendations for special needs dogs, they make recommendations based on calorie intake (per 100 kcal) so that recommendations are uniform for dogs of all sizes and various kibble choices.

We calculate the mg/100 kcal levels of sodium of a dog food by taking the AS FED sodium content, dividing it by the kcal/kg, and multiplying by 1,000,000.

For example, a food with a sodium level of 0.25 and 3701 kcal/kg yields 67.55 mg/100 kcal of sodium.

This is a food with a moderate sodium restriction and would be recommended for a dog with moderate heart disease with heart enlargement.

Which Sodium Content Levels Should YOU Be Looking At?

Which Value Matters Most

As Fed Sodium Content

Most dog foods do not list sodium content on their nutrition label, you have to request this from the company. For those who do list sodium content, however, these values are almost always provided “As Fed”. If requesting data from the company who makes the food, they will also almost always provide you with “As Fed” data.

This means that the only number you have relatively easy access to for sodium content is going to be the “As Fed” data. This will allow you to compare foods that have the same moisture content to see which offers lower sodium content.

Dry Matter Sodium Content

Dry matter sodium content is a number you have to calculate yourself, but it will allow you to compare various foods for their sodium content regardless of whether or not they have the same moisture content.

Dry matter sodium content is calculated by subtracting the moisture percentage of a food from 100% to get the dry matter of the food. Then you take the “As Fed” sodium content and divide that by the dry matter content. This will give you the dry matter sodium content of the food.

You can use dry matter sodium content to estimate sodium restriction levels, however, it is more accurate to use mg/100 kcal.


mg/100 kcal Sodium Content

mg/100 kcal is the most accurate measure of your dog’s sodium intake, but again, it is a number that you must calculate.

mg/100 kcal is calculated by taking the “As Fed” sodium content and dividing it by the kcal/kg listed on the back of the food bag. Now, multiply the resulting number by 1,000,000 and you will get the mg/100 kcal of sodium content for your dog’s food.

I know, it’s a lot of math, but fortunately, for the foods listed on the database here, I have done all that work for you. I will continue adding to this page as I find the time, so check back periodically for updates.

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Low Sodium Kibble – Which Value is Important?