"This information can save your life. Really."—Christiane Northrup, MD, New York Times bestselling author of Goddesses Never Age and Women's Bodies, Women's Wisdom Many Americans have succumbed to the scare tactics of the dermatological community, and avoid sunlight for fear of skin cancer and premature aging. Therefore, most of us suffer from vitamin D deficiency, which causes daily aches, pains, and fatigue, worsens serious illnesses, and diminishes the quality of everyday life. Drawing on decades of research, Dr. Michael f. Holick reveals a well-kept secret: our bodies need a sensible amount of unprotected sun exposure. The most comprehensive rescriptive book on the market, The Vitamin D Solution offers readers an easy and inexpensive plan to reversing the effects of vitamin D deficiency-and enjoying a substantially healthier life. “Following Dr. Holick's advice about vitamin D is possibly the single most important thing you can do to improve your health and save yourself from many chronic diseases, including cancer.”— David Servan-Schreiber, M.D., Ph.D. , author of international bestsellers The Instinct to Heal and Anticancer: A New Way of Life “Dr. Michael Holick has been a hero of mine for many years. How thrilling to have his ground-breaking research on vitamin D in one easily accessible book. This information can save your life. Really."— Christiane Northrup, M.D. , ob/gyn physician and author of the New York Times bestsellers: Women's Bodies, Women's Wisdom and The Wisdom of Menopause “Dr. Holick shows us why if you do one thing for your health beside eating well and exercising it MUST be getting more vitamin D through sun or supplements. Vitamin D deficiency affecting 200 million Americans is not just important for building strong bones but is absolutely needed to prevent and treat our chronic disease epidemic including heart disease, cancer, diabetes, depression, obesity, and autoimmune disease. The Vitamin D Solution , written by the world’s leading authority on vitamin D will surprise and delight you.”— Mark Hyman, MD , leading authority on nutrition and health and four time New York Times best-selling author including The UltraMind Solution and winner of the Linus Pauling Award. “Dr. Michael Holick's The Vitamin D Solution is an essential guide for women and men of all ages. As the leading vitamin D researcher in the country, Dr. Holick provides clear, practical, and scientifically based advice to help you improve your vitamin D nutrition and overall health.”— Miriam E. Nelson, Ph.D. , associate professor, Friedman School of Nutrition Science and Policy, Tufts University and the author of the bestselling "Strong Women" book series “I'm very pleased with the information presented in Dr. Holick's The Vitamin D Solution …[he] provides an understandable, well-written, and highly informative presentation about this unique vitamin, its history, its very important functions, problems with deficiency, and the steps to rebuild Vitamin D levels.”— Diane Kress, R.D. CDE , author of The Metabolism Miracle Michael F. Holick , Ph.d., M.D., is the director of the General Clinical Research Unit and professor of medicine, physiology, and biophysics at Boston University Medical Center. He has been quoted in The New York Times, Forbes, Time, Newsweek, Men’s Health , and Scientific American . He lives in Massachusetts with his family. CHAPTER 1 What Is Vitamin D? Is it a hormone or a vitamin? Somewhere along the equator a ten-year-old girl is growing up with- out the luxuries most of us enjoy on a daily basis. She will never learn how to use a computer, order a pizza to be delivered, or drive a car to the mall for clothes and cosmetics. She spends most of her days playing outside near her farming parents, and soon she will join them in tilling the soil. She will never learn to read or write. She will endure periods of poor nutrition and poverty. And she knows nothing about sunblock and probably never will. Now let’s sail north to the United States or Europe, where another ten-year-old girl leads an immensely different life. She is maturing into a savvy user of electronics, passes the majority of her days indoors at a rigorous school, has access to the best nutrition and all the benefits that modern medicine can provide, and will know what SPF means long before graduating from high school and pursing higher education. If both girls continue on their separate paths, the equatorial girl will be at least half as likely to get cancer during her lifetime as her northern counterpart. She also will have an 80 percent reduced risk of developing type 1 diabetes in the first thirty years of her life. In fact, barring any freak accident or untreated medical condition, her longevity overall will be 7 percent greater . The northern girl, on the other hand, faces a host of increased health risks throughout her life, from breast and ovarian cancer to depression, obesity, type 2 diabetes, oste