Effect of dietary protein level upon essential fatty acid (EFA) deficiency.

Rats were fed EFA-low diets containing vitamin-free casein varying from 5 to 40% and were assessed for severity of EFA deficiency by growth response, dermal symptoms and by the biochemical lesion of elevated triene/tetraene ratio in heart and liver lipids. The dermal signs of EFA deficiency increased in severity at levels of protein above 30%. The biochemical lesion of elevated triene/tetraene ratio in liver phospholipids was most severe at the lower protein levels. The two measures of EFA deficiency thus respond to different functions of EFA. Protein deficiency may thus increase the EFA requirement as measured by the biochemical criteria.