Kale

Vegetable growers harvest kale for its leaves. Ingredient suppliers wash and dry the leaves, then cut or mill them so pet food plants can blend small amounts into a recipe.¹⁰

1. 01 // Source Harvested leaves The edible leaf crop supplies the raw material; dried kale is made from leaves, not pressed vegetable residue.
2. 02 // Process Washed and sorted A supplier sorts, washes and trims fresh leaves before drying them.
3. 03 // Process Air dried Removing water makes the leaves suitable for shipment and storage as a dry ingredient.
4. 04 // Process Cut or milled The dry leaves become flakes or powder in the size a manufacturer requests.
5. 05 // Output Dried kale Pet food plants receive leaf flakes or powder that manufacturers weigh into a recipe.

1. 01

   Adds a little fiber

   Kale leaf solids contain soluble and insoluble fiber. The small amounts disclosed in dry foods limit how much that fiber contributes to the finished recipe.^3,9

2. 02

   Makes a vegetable visible

   A brand can name kale on the bag even when it sits low on the ingredient list. One herring food uses kale in its immune support pitch.^8,11

3. 03

   Blends in dry form

   Suppliers sell air dried kale as flakes or powder for pet food production. That lets manufacturers weigh and blend it without handling fresh leaves at the plant.¹⁰

How much An audit found 0.005 to 2% kale in dry foods that disclosed an amount; these were label figures, not feeding trials.⁹

1. Brands say

   Kale adds dietary fiber to food

   Evidence

   1. Strong
   2. Some
   3. Thin
   4. None

   A laboratory analysis measured 37.13% total dietary fiber in raw kale dry matter. Adding kale therefore adds fiber, although the small amounts disclosed on food labels limit its contribution to the full recipe.^3,9

2. Brands say

   Kale supports a dog's immune system

   Outruns the evidence

   Evidence

   1. Strong
   2. Some
   3. Thin
   4. None

   Researchers fed mice a water soluble kale extract for 14 days and measured antibody release from gut immune cells. They did not test whole kale in dogs, so that result does not support the brand's immune claim.^2,9,11

3. Brands say

   Kale antioxidants protect your dog

   Outruns the evidence

   Evidence

   1. Strong
   2. Some
   3. Thin
   4. None

   Kale contains antioxidant compounds, but boiling removed about 89% of vitamin C in one experiment. Laboratory chemistry and cooking studies do not show that a small amount of kale protects dogs from disease.^4,9,11

4. Brands say

   Kale in dog food prevents cancer

   Outruns the evidence

   Evidence

   1. Strong
   2. Some
   3. Thin
   4. None

   A case control study compared 92 Scottish Terriers with bladder cancer and 83 controls. Its cruciferous vegetable group had no statistically significant association with lower risk, and the researchers could not measure kale separately.¹

5. Owners say

   Kale in kibble causes bladder stones

   Outruns the evidence

   Evidence

   1. Strong
   2. Some
   3. Thin
   4. None

   A food chemistry review classifies kale as low in oxalate and reports none detected in one raw sample. It provides no evidence that the small amount in a complete dog food causes stones.^5,7