Most Americans have chronically low levels of Vitamin D because most of us do not get sufficient sunshine or Vitamin D-rich nutrition. Supplementation is an easy, inexpensive way to decrease your risk for cancer, rheumatoid arthritis, fibromyalgia, lupus, joint pain, the flu, and a variety of gastrointestinal problems, such as Crohn’s Disease. It’s best to talk with your doctor and have your current levels tested before taking supplements because in rare cases too much Vitamin D can cause toxicity. Over-the-counter supplements are not as effective as prescription Vitamin D.