doesnt meat, (along with foods like potatoes) provide some vit. C? could it be the grease is an unhealthy sourse of vitimins?
(i remember reading something about meat being a surprizing sourse of vit. C, when reading about the Atkin's diet.)

Scury existed because foods rich in vit. C were expensive (oranges or meat) or boring/gassy/socially unacceptable (cabbage). The english navy got sailer to take their lime juice by lacing it with rum.