Nikhil Prasad Fact checked by:Thailand Medical News Team Feb 06, 2026 1 hour, 46 minutes ago
Medical News: Vitamin D Deficiency and Lingering Post Covid Illness
A new clinical study from Japan is offering renewed hope to people suffering from long lasting fatigue and multiple unexplained symptoms after COVID-19 infection or vaccination. Many patients develop a condition known as myalgic encephalomyelitis or chronic fatigue syndrome, marked by extreme tiredness, brain fog, sleep disturbances, pain, dizziness, and worsening symptoms after physical or mental effort. Researchers suspected that low vitamin D levels might be playing a critical role in worsening or prolonging these symptoms.
Medical-News-Vitamin-D-Shows-Hope-Against-Post-COVID-Fatigue-Syndrome
Why Researchers Focused on Vitamin D
Vitamin D is known to influence immune balance, inflammation control, and nerve health. Earlier observations showed that many patients who developed chronic fatigue after COVID-19 vaccination or infection had insufficient or deficient vitamin D levels. This
Medical News report explores whether correcting that deficiency could meaningfully improve daily functioning and reduce symptom burden.
How The Study Was Conducted
The randomized controlled trial involved 91 adults diagnosed with chronic fatigue syndrome following either COVID-19 infection or vaccination. All participants had low blood levels of vitamin D. The study was conducted across five medical centers in Japan. Participants were divided into two groups. One group received standard active vitamin D medication alone. The other group received the same medication plus structured vitamin D replacement guidance, including daily vitamin D supplementation, dietary advice, sunlight exposure, and light exercise.
Clear And Measurable Improvements Seen
After 12 weeks, patients receiving the full vitamin D replacement guidance showed striking improvements. On average, they experienced a reduction of nearly seven symptoms, compared to just over one symptom in the control group. Blood vitamin D levels rose significantly in the guided group, while levels in the control group barely changed. Importantly, 16 patients in the guided group improved enough that they no longer met diagnostic criteria for chronic fatigue syndrome, compared to only one patient in the control group.
Benefits Seen in Both Long COVID and Post Vaccine Cases
The improvements were consistent whether symptoms followed COVID-19 infection or vaccination. Patients reported better sleep, reduced pain, improved immune related symptoms, and less post exertional exhaustion. Safety monitoring showed no serious vitamin D related side effects, and laboratory values remained stable.
What These Findings Mean for Patients
The results suggest that simple and affordable vitamin D correction strategies may offer meaningful relief for people struggling with long term post COVID fatigue conditions. The study also highlights that active vitamin D medication alone may not be sufficient to correct deficiency or improve symptoms without
proper supplementation and lifestyle guidance.
Conclusion
This study provides strong clinical evidence that addressing vitamin D deficiency can significantly reduce symptom severity in chronic fatigue syndrome linked to COVID-19 infection or vaccination. While vitamin D is not a cure, restoring healthy levels appears to support immune balance, reduce inflammation, and improve overall symptom burden, offering a practical therapeutic option for a condition with limited existing treatments.
The study findings were published in the peer reviewed journal: Nutrients.
https://www.mdpi.com/2072-6643/18/3/521
For the latest on Long COVID, keep on logging to Thailand
Medical News.
Read Also:
https://www.thailandmedical.news/articles/long-covid
https://www.thailandmedical.news/articles/coronavirus
https://www.thailandmedical.news/articles/supplements
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