Whole-food sources of vitamin A more effectively inhibit female rat sexual maturation, mammary gland development, and mammary carcinogenesis than retinyl palmitate.
McDaniel SM, O'Neill C, Metz RP, Tarbutton E, Stacewicz-Sapuntzakis M, Heimendinger J, Wolfe P, Thompson H, Schedin P. Whole-food sources of vitamin A more effectively inhibit female rat sexual maturation, mammary gland development, and mammary carcinogenesis than retinyl palmitate. J Nutr. 2007 Jun; 137(6):1415-22.