When Brighton Township rheumatologist James Dowd moved from Texas to Michigan in the mid-1990s, he started to notice changes in his health. He became fatigued and his joints got stiff.

"I started to experience the same symptoms as my patients, who are often labeled as having fibromyalgia," says Dowd. "I decided to change my diet and began taking vitamin D, and I felt better. When my patients started taking vitamin D, it helped them, too."

So Dowd, who also is an associate professor of medicine at Michigan State University, began reading everything he could about vitamin D. Earlier this year his book, "The Vitamin D Cure," written with Diane Stafford, was published by Wiley.