The biochemical and physiological role of vitamins A and E and their interactions.

The therapeutic applications of vitamin A and vitamin E are reviewed, with special references to their role in the retinal functions, epithelial differentiation and maintainance, deficiency due to liver diseases and malabsorption, antioxidant activity, membrane protection, and antiatherogenic function. The interference between the two vitamins and their synergism is discussed on the basis of the protective role of tocopherol on retinol. From experimental studies on chicken, a mathematical model linking the optimal plasma value of the two vitamins is obtained.