Could one of the most important substances in human health also be one of the most overlooked? Best known for its essential role in building and maintaining healthy bones, vitamin D3 has become the subject of an enormous body of medical research. Scientists have investigated its relationships with the immune system, muscles, brain, cardiovascular system, metabolism, reproduction, inflammation, and numerous aspects of physical and psychological health. Yet despite decades of research, vitamin D3 deficiency and insufficiency remain widespread concerns. In Vitamin D: The Miracle Treatment for Nearly Every Disease and Health Issue , award-winning author and independent researcher Lochlainn Seabrook explores this remarkable substance-not merely a vitamin, but a compound whose active form functions as a hormone within the human body. Written as an accessible introduction to vitamin D science and alternative and complementary approaches to health, this heavily researched volume examines its history, chemistry, biological functions, dietary sources, relationship to sunlight, recommended intake, supplementation, and role in human nutrition and general well-being. At the heart of the book is an extraordinary reference section covering more than 1,000 diseases, disorders, symptoms, and health conditions that have appeared in vitamin D-related medical and scientific literature. Subjects range from common concerns involving bones, teeth, muscles, sleep, mood, digestion, and immunity to research involving cancer, cardiovascular disease, dementia, osteoporosis, infertility, depression, Parkinson's disease, tuberculosis, endometriosis, and numerous other conditions. Rather than asking readers simply to accept these connections, Seabrook points them toward the research itself. Generously illustrated in color, the book contains some 1,200 endnotes, 54 pages of sources, an extensive bibliography, nutritional conversion tables, and a detailed 20-page index, along with historical appendices examining the controversy surrounding vitamin D3 regulation and statements made by members of Congress during the 1973 debate over FDA policies affecting vitamins and nutritional supplements. Combining health guide, research compendium, historical study, and reference work, Vitamin D offers readers interested in nutrition, natural health, complementary medicine, supplementation, sunlight, and preventive health an information-packed starting point for their own investigation.