Vitamin D supplements can improve the symptoms of a debilitating chronic pain disorder that affects around one in 25 people, mostly women.

Fibromyalgia syndrome (FMS) causes widespread muscle pain and tiredness, and is associated with anxiety and depression.

Sufferers are highly sensitive to touch, so that even a minor knock can be extremely painful.

The incurable condition, often confused with chronic fatigue syndrome, or ME, is believed to be triggered by abnormally sensitive nerves.

Previous studies have shown that low levels of vitamin D are common in patients with FMS.

In the new study, 30 women with the syndrome who were lacking vitamin D were either given supplements of the vitamin or an inactive placebo.

Boosting vitamin D levels led to dramatic reductions in the treated group’s experience of pain, as measured using a standard scale based on self-reported symptoms.

Vitamin D levels should be monitored regularly in FMS patients, especially in the winter season, and raised appropriately

The improvement continued over 25 weeks until the supplements were stopped, after which both groups had matching pain scores.

Treated women also experienced a significant reduction in morning fatigue, although the supplements had no impact on depression and anxiety symptoms.

The findings are reported in the current issue of the journal Pain.

Study leader Florian Wepner, from Speising Orthopaedic Hospital in Vienna, Austria, said: “We believe that the data presented in the present study are promising. FMS is a very extensive symptom complex that cannot be explained by a vitamin D deficiency alone.

“However, vitamin D supplementation may be regarded as a relatively safe and economical treatment for FMS patients and an extremely cost-effective alternative or adjunct to expensive pharmacological treatment as well as physical, behavioural, and multimodal therapies.

“Vitamin D levels should be monitored regularly in FMS patients, especially in the winter season, and raised appropriately.”