Response to vitamin B12 and folic acid in myalgic encephalomyelitis and fibromyalgia.
Regland, Björn, Forsmark, Sara, Halaouate, Lena et al. · PloS one · 2015 · DOI
Quick Summary
This study looked at 38 ME/CFS patients who were receiving vitamin B12 injections and oral folic acid to see how well this treatment worked for them. Patients who improved the most received more frequent injections at higher doses, took more folic acid, and were less likely to use strong pain medications like opioids. The researchers found that this treatment combination showed real benefits for some patients, particularly when carefully matched to individual needs.
Why It Matters
This study provides clinical evidence that B12/folic acid therapy may benefit some ME/CFS patients and identifies potentially important modifying factors like MTHFR genotype status, thyroid function, and concurrent medication use. These findings could inform more personalized treatment approaches and highlight the need for controlled trials that account for drug interactions and individual methylation capacity.
Observed Findings
Good responders used significantly more frequent B12 injections and higher doses than Mild responders (p<0.03)
Good responders maintained treatment for longer durations and took higher daily folic acid doses (p<0.0005 and p<0.003)
Approximately 70% of Mild responders used daily opioid or other strong analgesics, compared to none in the Good responder group (p<0.0005)
Good responders more frequently used thyroid hormones (p<0.02)
Good responders reported 'very much' or 'much' improvement while Mild responders reported 'much' or 'minimally' improved outcomes
Inferred Conclusions
Dose-response and temporal relationships support a true therapeutic effect of B12/folic acid in ME/CFS and fibromyalgia, not merely placebo
Treatment response may depend on MTHFR genotype-matched folic acid dosing and attention to thyroid dysfunction
Concurrent use of opioids and other demethylation-dependent medications may interfere with B12/folic acid treatment efficacy
Remaining Questions
What are the optimal individualized B12 and folic acid dosing algorithms based on MTHFR genotype and other biomarkers?
Does the apparent interference between analgesics and B12/folic acid reflect a true pharmacological interaction, or does it indicate that patients requiring opioids have more severe disease?
What This Study Does Not Prove
This observational study cannot establish causation or optimal dosing protocols—it only describes associations in a small, self-selected group who remained on treatment. The lack of a control group means improvements could reflect placebo effect, natural history, lifestyle changes, or selection bias favoring responders. The finding that analgesic use correlates with poor response does not prove analgesics caused worse outcomes; patients in greater pain may simply have worse underlying disease.