Fatty Acid Estimations

You may have noticed that the RFN Spreadsheet (single and pack) has an asterisks next to three particular fatty acids. This denotes that these fatty acids use estimated values.

Why Values are Estimated

The RFN Spreadsheet is based on the USDA food database, specifically SR Legacy data, which means that we are limited to the nutritional analysis that is provided. Unfortunately, not every food listed by the USDA contains information on all nutrients. Typically, with fatty acids, general (or undifferentiated) values are measured, but not specifically the n-3 or n-6 types.

For example, let’s look at raw chicken and 18:3 fatty acids. USDA lists 18:3 undifferentiated, but does not list any more specific information about the subtypes, ALA, the omega-3 of 18:3, or GLA, the omega-6 of 18:3. This doesn’t mean that the chicken does not have those fatty acids – it just means that the analysis was not that specific.

Dogs and cats have requirements for LA, ALA and AA, which poses an issue during formulation because the data is frequently missing from nutrient analysis. The options are then to:

  1. Assume the food does not have any amount off those fatty acids and choose to use a supplement that specifically lists that fatty acid, which may result in diets that are higher in fat
  2. Determine, through estimation, how much of that particular fatty acid might be in the food.

The RFN Spreadsheet uses the second option.

Estimation Specifics

Linoleic acid – 18:2 n-6

Data available for about half of database items. When nutrient information is missing, 18:2 undifferentiated values are substituted.

alpha-linolenic acid – 18:3 n-3

Data is available for about half of database items. When nutrient information is missing, 18:3 undifferentiated values are substituted.

Arachidonic acid – 20:4 n-6

Data is missing for almost all database items. When nutrient information is missing, 20:4 undifferentiated values are substituted.

Associated Issues

Currently, because LA*, ALA* and AA* are estimated, saving a recipe does not use those values when saving nutrient values. When saving a recipe, it pulls the “true” or non-estimated values for these fatty acids.

This means that when you look at your recipe in the recipe builder, or use a recipe as a food ingredient, the fatty acids may be a lot lower than the estimated values when you were originally formulating.

This happens because the recipe, as a single ingredient, usually has a very small or partial value for LA/ALA/AA, and the spreadsheet only estimates them when they are 0.

This will be fixed in a future update, as we work on a better way to rely on estimations.

In the mean time, some solutions:

  • When saving a recipe, you can manually go into the Food Database and rewrite the value under each of these fatty acids, with the estimated value in your recipe builder
  • When looking at a saved recipe, you can look at and work with the undifferentiated fatty acid total