Kodama et al. (2026)
- Authors: Shinichiro Kodama, M. Nakata, Masanori Fukushima
- Institutes: Kodama Clinic, Hyogo, Japan, Kyoto Prefectural University of Medicine, Kyoto, Japan, Foundation of Learning Health Society Institute, Nagoya, Japan
- Publisher: Nutrients
- Link: DOI
Summary
This trial demonstrates that a comprehensive vitamin D restoration protocol can significantly alleviate symptoms in patients who developed ME/CFS following COVID-19 or vaccination. The findings are particularly impactful as they suggest that a subset of ‘Long COVID’ and post-vaccination cases may be driven by or exacerbated by severe vitamin D deficiency. By correcting these levels through a combination of supplementation and lifestyle changes, a significant portion of patients reached a state where they no longer met the clinical diagnostic criteria for ME/CFS.
What was researched?
The study investigated whether a comprehensive vitamin D 💊 replacement therapy protocol could improve symptoms in patients with ME/CFS triggered by COVID-19 or vaccination. Researchers specifically focused on patients who also presented with vitamin D insufficiency or deficiency.
Why was it researched?
Previous retrospective data indicated a high prevalence of low vitamin D levels among patients with post-vaccination syndrome. The researchers sought to confirm if targeted correction of these levels could serve as an effective treatment for the resulting ME/CFS symptoms.
How was it researched?
This open-label randomized controlled trial enrolled 91 participants with post-viral or post-vaccination ME/CFS and serum vitamin D levels below 30 ng/mL. The intervention group received an active vitamin D preparation plus ‘replacement therapy guidance’ consisting of daily D3 supplements, dietary counseling, sun exposure, and light exercise. The control group received the active vitamin D preparation (alfacalcidol 💊) alone without the additional guidance and supplements.
What has been found?
The intervention group showed a significant reduction in the mean number of ME/CFS symptoms compared to the control group after 12 weeks. Serum vitamin D levels rose significantly in the intervention group while remaining stagnant or declining in the control group. Notably, 16 participants in the intervention group improved so significantly that they no longer met the diagnostic criteria for ME/CFS, compared to only one in the control group. Subgroup analysis confirmed that these benefits were consistent across both post-COVID and post-vaccination cohorts.
Discussion
The study is limited by its open-label design, which may introduce participant bias, and the multi-component nature of the intervention makes it difficult to isolate the effect of supplementation from lifestyle changes. However, the strong correlation between rising serum levels and symptom relief supports the biological relevance of the treatment. The use of alfacalcidol in the control group suggests that standard medical vitamin D analogues may be less effective than comprehensive replacement protocols for this population.
Conclusion & Future Work
Comprehensive vitamin D replacement guidance is a safe and effective method for reducing ME/CFS symptoms in patients with confirmed deficiency. Future research should explore the long-term sustainability of these improvements and the underlying mechanisms of vitamin D in neuro-immune recovery.