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By Alan Cocchetto, NCF Medical Director © 2015

From Summer 2015 Forum

The “Just Ask!” column is intended to act as a means for patients to inquire about issues related to the NCF’s research activities. This column is NOT intended to act as medical advice in any way, shape or form! The National CFIDS Foundation assumes no responsibilities for any action or treatment undertaken by readers. For medical advice, please consult your own personal healthcare providers

Q: What does the medical literature say about Vitamin D and CFIDS/ME?

A: This is a good question. Since many patients with this disease are sensitive to the sun, I went to Pubmed to search for answers. Here is what I found

Going back a few years in the medical literature revealed that CFIDS/ME patients have sub-optimal levels of serum 25-hydroxy Vitamin D in their blood [1]. The authors tested 221 patients in this study. They suggest that that due to these low Vitamin D levels, patients may have an increased risk for the development of osteoporosis and therefore should consider Vitamin D supplementation.

Well, if we fast-forward a couple of years, we find that these patients have impaired vascular health [2]. The authors of this study tested whether high-dose intermittent oral vitamin D therapy improved markers of vascular health and fatigue in patients with CFS. After testing Vitamin D3 supplementation on fifty patients over a six month duration, these authors concluded that high-dose oral vitamin D3 did not improve markers of vascular health or fatigue in these patients.

As such, given this brief look at Vitamin D, you may draw your own conclusion regarding the usefulness of this therapy. I certainly encourage patients to discuss this with their own physicians.


  1. Serum 25-hydroxy vitamin D levels in chronic fatigue syndrome: a retrospective survey; Berkovits S, Ambler G, Jenkins M, Thurgood S; Int J Vitam Nutr Res. 2009 Jul;79(4):250-4.

  2. Effect of intermittent vitamin D3 on vascular function and symptoms in chronic fatigue syndrome — a randomised controlled trial; Witham MD, Adams F, McSwiggan S, Kennedy G, Kabir G, Belch JJ, Khan F; Nutr Metab Cardiovasc Dis. 2015 Mar;25(3):287-94.

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