Milk protein depletes Vitamin A more than gluten/zein

[Gabriel]

Dietary Protein and Utilization of Vitamin A
J. Nutr. 1962 76: 435-440

This interesting study in rats showed:

1. On a protein-deficient diet Vitamin A accumulates in the liver, suggesting that less of it is used by the body
2. The more protein the mice get, the less Vitamin A is stored in their liver, suggesting that higher protein intake requires more Vitamin A
3. A diet high in milk protein (casein) depletes Vitamin A stores more than equal amounts of other protein (gluten or zein)

All in all, well in line with Peat's observation that a high-milk diet requires a higher intake of Vitamin A.
Interestingly, this effect was related to the protein fraction of milk and not the calcium or fat content.

 

[pboy]

interesting...I can't even think of the mechanism behind why that would be happening...perhaps more quality protein tells the body its ok to make more hormones so more vitamin A is spent