Patients with fibromyalgia syndrome suffer from chronic, body-wide muscle and joint pain, and fatigue. Previous studies have pointed to the possible role of vitamin D in the perception of chronic pain.
In the new study, researchers studied whether raising patients' vitamin D levels to the recommended range would help with some of their symptoms. Thirty patients with fibromyalgia who also had low levels of vitamin D in their blood (below 32 nanograms per milliliter) were randomly assigned to take either oral vitamin D supplements, or a placebo, for 20 weeks.
Weeks after the treatment ended, patients who took the supplements were still experiencing reduced pain, while people who had taken placebo didn't see a change in their pain level, according to the study, published today (Jan. 17) in the journal Pain.
"Vitamin D supplementation may be regarded as a relatively safe and economical treatment" for people with fibromyalgia," said study researcher Dr. Florian Wepner, an orthopedist at the Orthopaedic Hospital Speising in Vienna.
However, the vitamin is not a cure for the condition, Wepner said. Fibromyalgia "cannot be explained by a vitamin D deficiency alone," he said. And although the patients who took vitamin D saw reductions in their pain, there were no significant changes in their depression or anxiety symptoms.
Fibromyalgia affects about 2 percent of the U.S. population, and is more common in women than in men, according to the Centers for Disease Control and Prevention. No treatments are available that address all symptoms of the condition, but some symptoms may be alleviated by physical therapy, cognitive behavioral therapy and temporary drug therapy.
Vitamin D is present in very few foods, but is produced by the skin after exposure to ultraviolet rays from sunlight. It can be found in fortified foods, such as milk, orange juice and cereals as well. Too much vitamin D has its risks, too — it can cause damage to the heart and kidneys. [9 Good Sources of Disease-Fighter Vitamin D]
Low levels of vitamin D are especially common in patients with severe pain and fibromyalgia, the researchers said.
"Vitamin D levels should be monitored regularly in fibromyalgia patients, especially in the winter season, and raised appropriately," Wepner said.