Wheat Bran

Flour mills remove wheat's outer layers to make refined flour. The separated material, often mixed with finer milling leftovers, becomes wheat bran for feed. Its makeup depends on how the mill separates the grain.⁵

1. 01 // Source Wheat kernels Whole kernels enter the flour mill with outer layers surrounding a starchy center.
2. 02 // Process Cleaned and tempered The mill removes impurities and moistens the kernels so their outer layers separate more readily.
3. 03 // Process Ground and separated Successive grinding produces fine flour and coarser bran, which retains some starchy material.
4. 04 // Output Wheat bran The separated bran reaches feed makers as a dry milling product with variable fiber and starch.

1. 01

   Adds stool bulk

   Bran brings cell wall fiber into the food. A controlled dog study found more fecal output when bran replaced part of a similar kibble.¹

2. 02

   Supplies fermentable fiber

   Dogs fed a high bran diet had more short chain fatty acids in their feces. That shows some fermentation; the study did not measure a health benefit.¹

3. 03

   Uses a milling commodity

   Flour mills already separate bran from wheat, producing a major feed commodity. Kibble makers get a widely available fiber ingredient from that milling stream.⁵

4. 04

   Swaps for other fibers

   A 30-dog trial fed bran and four other fibers at equal total fiber. Digestible and metabolizable energy were generally similar across them, so bran can stand in for other fiber sources.²

How much A controlled dog study tested wheat bran at 25% of a complete kibble, an experimental amount rather than a published typical amount.¹

1. Critics say

   Large amounts of wheat bran reduce digestibility

   Evidence

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

   Two small controlled trials, 6 dogs per diet and 5 dogs per treatment, found lower dry matter digestibility with bran or added fiber than with control diets. The fiber level differed between the two designs, and neither tested a dose range.^1,2

2. Brands say

   Wheat bran adds bulk to stools

   Evidence

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

   In a 30-dog trial, foods with 25% bran produced more feces than bran-free food. That supports increased bulk at a high amount; it does not guarantee firmer stools in an ordinary recipe.¹

3. Brands say

   Prebiotic wheat bran improves gut health

   Outruns the evidence

   Evidence

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

   The 30-dog bran trial recorded more fecal short chain fatty acids and lower pH, signs of fermentation. It did not test illness or comfort at ordinary recipe amounts, so improved gut health is unproven.¹

4. Owners say

   Wheat bran relieves constipation

   Outruns the evidence

   Evidence

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

   In 7 healthy dogs, 7.7 g bran added to a canned meal did not significantly change transit time. A separate high bran diet increased fecal output, but neither study treated constipated dogs.^1,3

5. Critics say

   Wheat bran is just filler

   Outruns the evidence

   Evidence

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

   At 25% of a diet, bran changed fecal output and fermentation in 30 dogs; its dry matter also includes starch and protein. It has a job, although high amounts lower diet digestibility.^1,6