This is a study posted in the 1938 Journal of Nutrition with some interesting correlations of Vitamins A, D, C, and B1. Since this is a rat study, if someone can translate the dosages into human equivalents it would be helpful. But even without the human interpretation it is obvious the units of Vitamin A were outrageous for a 50 grm weight animal. For these amounts to be neutralized by Vitamin C is amazing. Also interesting is the correlation between different doses of Vitamin D in relation to the amount of Vitamin A ingested.