Berkovitz, Saul, Ambler, Gareth, Jenkins, Michael et al. · International journal for vitamin and nutrition research. Internationale Zeitschrift fur Vitamin- und Ernahrungsforschung. Journal international de vitaminologie et de nutrition · 2009 · DOI
This study measured vitamin D levels in 221 ME/CFS patients and found they were significantly lower than in healthy people from the general British population. Because ME/CFS patients often spend less time outdoors and are less physically active, they may not get enough sun exposure to produce adequate vitamin D naturally. The researchers suggest that ME/CFS patients should try to get more sunlight and eat vitamin D-rich foods, and may benefit from vitamin D supplements if levels remain low.
Vitamin D deficiency may contribute to bone health complications in ME/CFS patients, who are at particular risk due to reduced mobility and indoor confinement. This study provides quantitative evidence supporting official clinical guidelines for vitamin D monitoring and supplementation in this population, offering a potentially modifiable factor that could improve long-term health outcomes.
This study does not establish whether low vitamin D is a cause of ME/CFS symptoms or merely a consequence of reduced activity and sun exposure. It cannot prove that vitamin D supplementation will improve ME/CFS symptoms or fatigue, nor does it demonstrate causation for any associated complications. The cross-sectional design means the direction of association cannot be determined.
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →
The first block is for the primary paper and is the citation you should use in research work. The atlas-snapshot line only applies if you are specifically referring to this atlas’s reading of the paper on the date shown.
Primary citation
Berkovitz, Saul, Ambler, Gareth, Jenkins, Michael, & Thurgood, Sue (2009). Serum 25-hydroxy vitamin D levels in chronic fatigue syndrome: a retrospective survey.. International journal for vitamin and nutrition research. Internationale Zeitschrift fur Vitamin- und Ernahrungsforschung. Journal international de vitaminologie et de nutrition. https://doi.org/10.1024/0300-9831.79.4.250
BibTeX
@article{mecfsatlas-berkovitz-2009-serum-hydroxy,
author = {Berkovitz, Saul and Ambler, Gareth and Jenkins, Michael and Thurgood, Sue},
title = {Serum 25-hydroxy vitamin D levels in chronic fatigue syndrome: a retrospective survey.},
journal = {International journal for vitamin and nutrition research. Internationale Zeitschrift fur Vitamin- und Ernahrungsforschung. Journal international de vitaminologie et de nutrition},
year = {2009},
doi = {10.1024/0300-9831.79.4.250},
note = {PubMed: 20209476},
url = {https://www.mecfsatlas.com/evidence/berkovitz-2009-serum-hydroxy},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-29. https://www.mecfsatlas.com/evidence/berkovitz-2009-serum-hydroxy
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