Vitamin B12 may help fibromyalgia symptoms

5 minute read

But Australian experts say that while promising, the trial’s shortcomings mean there’s not enough evidence to warrant prescribing it.

Women with fibromyalgia who took vitamin B12 had an improvement in their symptoms and anxiety levels, a small Iranian study has found.

“This study showed that a short course of sublingual vitamin B12, 1000 mcg daily, can significantly improve the severity of fibromyalgia as well as the anxiety score of fibromyalgia patients,” the authors wrote, adding that there was no improvement in depression scores or health status scales.

But Australian rheumatologists, who were not involved in the research, said the study had several limitations that made it difficult to draw any conclusions or recommend B12 for fibromyalgia patients. Nevertheless, they agreed it was an interesting line of research.

The open-label, pre-post study, published in BMC Rheumatology, included 28 women who took 1000mcg of vitamin B12 a day for nearly two months. Patients completed surveys before and after treatment to measure symptom severity, overall function, pain, depression and anxiety.  

Patients were excluded if they had any comorbid nociceptive or neuropathic chronic pain or inflammation, as were patients at risk of vitamin B12 deficiency. Patients were asked to stop taking any supplement containing vitamin B12 for two weeks before the study.

After 50 days, there were statistically significant improvements in the patients’ fibromyalgia impact questionnaire scores, the primary outcome, as well as their function and anxiety scores.

However, there was no overall improvement in depression symptoms, pain scores or in the results of a 12-item short form health survey.

The authors acknowledged that the study was short and also did not include a placebo arm, “because providing the placebo form of sublingual vitamin B12 was very difficult”.

They also said vitamin B12 was given as an adjuvant drug with patients’ current treatment regimen, including fibromyalgia drugs, and that may have changed the effect of vitamin B12.

Melbourne-based rheumatologist Dr Daniel Lewis said it was a very small observational study and the rationale was not based on any pain inhibition mechanisms.

“There is a lot of evidence to suggest that individuals with fibromyalgia have, compared to the general population, low B12 and vitamin D levels,” he told Rheumatology Republic. 

“Those that prescribe vitamins as a primary treatment modality, such as naturopaths, will love this study and feed on it.

“I have never come across an open-label study with small numbers of participants, using any treatment modality in fibromyalgia, that does not produce a similar positive result, from acupuncture to hands-on healing,” Dr Lewis said.

Dr Emma Guymer, a rheumatologist at Monash Health, told Rheumatology Republic there had not been any large, randomised placebo-controlled trials looking at B12 supplementation in patients with fibromyalgia with or without B12 deficiency.

“This is an interesting study and an area that should be investigated, given B12 links to neurological health. This study is an initial foray into the question; however, it is too small and not appropriately designed to provide definitive answers,” Dr Guymer said.

The improvement gained from regular medical follow-up cannot be excluded, she said.

Geoffrey Littlejohn, adjunct clinical professor at Monash University, said the concept needed clarification in a well-conducted double-blind placebo-controlled study. 

“The study design did not have a placebo arm and in a condition such as fibromyalgia, where placebo effects are high, it is difficult to draw any firm conclusions from the results,” Professor Littlejohn told Rheumatology Republic.

“I would not recommend vitamin B12 for patients based on this evidence, but will follow developments about this potential adjunctive therapy.”

Rheumatologist Dr Samuel Whittle, of The Queen Elizabeth Hospital in South Australia, told Rheumatology Republic there were several problems with the study.

“We expect to see improvements in groups that are followed like this, due to both placebo effects and regression to the mean. Improvements are the norm, so the fact that they saw an improvement doesn’t tell us anything, Dr Whittle said.

The researchers did not measure participants’ baseline vitamin B12 before treatment with B12 – and that was another problem, Dr Whittle said.

“We don’t know whether the participants were B12 deficient and were being made B12 replete, or whether they were B12 replete to start with and this was additional B12, which would be important to know if you did think that this were an effective therapy.”

Dr Whittle said there were some effective pharmacotherapies for fibromyalgia such as duloxetine or pregabalin.

“But even in those, the effect sizes are relatively small, and in the clinic the results are often more disappointing than the trials would suggest.”

Dr Whittle said due to the nature of fibromyalgia, there was unlikely to be a “magic bullet” or single receptor pharmacotherapeutic intervention that was broadly or substantially successful in most people with fibromyalgia.

“I think we’d do a much better service to their fibromyalgia community by putting our heads down and coming up with reliable trial results that we can then work to institute in the clinic.”

BMC Rheumatology 2022, online 1 September

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