Carotenoids and retinoids: a review of research, clinical, and public health applications.

Traditionally, the carotenoids and retinoids have been regarded as dietary sources of vitamin A and have been evaluated regarding their respective physiologic roles in vision, growth, immune system integrity, and prevention of vitamin A deficiency. In the 1990s, however, vitamin A deficiency is no longer widespread in Western countries. Therefore, the role of carotenoids and retinoids is evolving to encompass treatment and prevention of conditions such as cancer and cardiovascular disease, which are prevalent in Western societies. This review summarizes current research concerning the therapeutic utility of vitamin A and its analogues and their roles in the prevention of cancer and cardiovascular disease.