Introduction

This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book focuses on intriguing studies indicating that methylselenol and its metabolites act to block capillary endothelial cell migration into mammary tumors via inhibitory effects at the level of matrix metalloproteinases and tumor vascular endothelial growth factor production. It traces the historical development of the relationship between selenium and cancer, showing that selenium can, under specific conditions, be toxic, an essential nutrient, and an anticarcinogenic and antiangiogenic agent. The book discusses the paradigm shift from the concept of nutrient sufficiency to that of optimal nutrition as it applies to chronic disease prevention. It reviews summarizes the rationale for use of a discovered organic selenium compound in human populations. The book describes several clinical trials under way designed specifically to evaluate whether selenium supplementation can reduce the incidence of prostate cancer in high-risk populations.