D Is for Defense: Why Vitamin D Is the Ultimate Super Vitamin

New Research on Vitamin D

Billie Jo Coomer, 31, couldn't figure out what the heck was wrong with her. For more than six years she had suffered from headaches and pain in her stomach, back, arms, and legs. "I hurt constantly and couldn't sleep at night," says Billie Jo, an administrator in St. Clair Shores, Michigan. She saw more than a dozen doctors, but all they did was prescribe painkillers and antidepressants.

She dragged through each day, suffering constantly from colds and bouts of pneumonia. Finally, in 2006, she was referred to a physician who made a startling diagnosis: Billie Jo was deficient in vitamin D. She started taking supplements in December, and "by February, I was off antidepressants," she says. Her pain gradually eased, she was able to sleep at night and her stamina returned. She even lost 29 pounds in three months. "I'm a completely different person than I was two years ago," she says. "I can't believe the fix was so easy."

Groundbreaking new research shows that D not only relieves health conditions like Billie Jo's but is also crucial for protecting against cancer, diabetes, depression, and heart disease. It also helps prolong our lives. A study published last summer found that people with the highest levels of D in their blood are 21 percent less likely to die of any cause than people with the lowest. While other nutrients, like vitamin E, have proved disappointing in similar large studies, "there really seems to be something super-protective about D," says study coauthor Michal Melamed, MD, an assistant professor of medicine, epidemiology and population health at Albert Einstein College of Medicine in New York City.

But the scary thing is, as many as 78 percent of Americans don't have the amount of vitamin D necessary for good health, according to the Office of Dietary Supplements in Washington, D.C. One-third of the population -- mostly women -- fail to meet even the current minimum. As many as half of young adults are low in D, putting them at risk for developing a rare bone disorder called osteomalacia. Unlike osteoporosis, which is characterized by bone loss, the condition causes the skeleton to soften from a lack of calcium, resulting in aches and pains throughout the body. "Some patients have bones that look almost clear on x-rays," says Michael F. Holick, MD, PhD, director of the Bone Health Care Clinic at Boston University School of Medicine.

Vitamin D deficiency is so widespread that it has become a serious health problem for women and men of all ages, experts say. Yet most of us have no idea we're at risk.