Friday, 2 January 2015

Vitamin D and Chronic Fatigue Syndrome continued

Hello again and a very warm welcome back to Questioning Answers in 2015. The year, according to a popular sequel, we were all supposed to be benefiting from hoverboards and wearing self-drying clothes. It didn't quite work out like that (although there are still 52 weeks left for such dreams to come to fruition).
When we got adopted by a bald guy,
I thought this would be more like Annie.

We start the new blogging year with a few comments on a rather interesting, if disappointing, set of results published by Miles Witham and colleagues [1] who concluded: "High-dose oral vitamin D3 did not improve markers of vascular health or fatigue in patients with chronic fatigue syndrome." Based on the use of a "Parallel-group, double-blind, randomised placebo-controlled trial" looking at the use of oral vitamin D3 (cholecalciferol) on a small-ish group of participants diagnosed with chronic fatigue syndrome (CFS), researchers concluded that a super dose of 100,000 IU (international units) delivered every 2 months over a period of 6 months showed little effect over placebo either on reports of fatigue or "arterial stiffness measured using carotid-femoral pulse wave velocity at 6 months." The ISRCTN entry for the study can be seen here and some previous discussion on vascular health, vitamin D and CFS by the authors can be seen here.

I say that these are disappointing results because, not so long ago, we were getting a few research hints that vitamin D deficiency might be quite frequent an occurrence in relation to CFS (see here) and supplementation might be indicated for some (see here). Indeed, given the recent news from NICE here in England about improving access to vitamin D supplementation for certain groups (see here), one had hoped that CFS may have been included under one of those population categories.

But...

I might however point out a few details from the Witham study which perhaps mean that it is not all bad news for vitamin D and CFS. The authors report that the: "mean baseline 25-hydroxyvitamin D level [was] 46 (18) nmol/L" (the bracketed part refers to the SD). A quick conversion from nmol to ng (1.0 nmol/L = 0.4 ng/mL) suggests that the mean circulating vitamin D level in their CFS group was 18.4 ng/mL which, by my reckoning, puts quite a few participants in the moderate deficiency category. Indeed, such results are comparable with what has been reported in other conditions (see here) bearing in mind the difference between mean and median.

Witham et al also report using vitamin D3 at 100,000 IU every 2 months for 6 months. 100,000 IU sounds like quite a lot but let me put this into some perspective. At a mean participant age of 49 years, those taking part in the trial should have been getting 600 IU daily according to US NIH guidance. If we assume there are 60 days in 2 months, this means an intake of 36,000 IU would have already been recommended. The study therefore added 64,000 IU per 2 months. In effect, participants received a daily dose of about 1600 IU per day (1000 IU extra per day as a consequence of the supplement). Consider also that in cases of vitamin D insufficiency - sometimes talked about as being below 30 ng/mL - other authors have reported the use of 100,000 IU of vitamin D3 every two weeks [2] as required to bring levels up to where they should be. I say this providing nothing that looks, sounds or smells like medical or clinical advice.

Finally, as per my discussions on the rather more 'open' methodology used in the Roy paper [3] looking at vitamin D supplementation and fatigue scores, their chosen vitamin D supplement was ergocalciferol otherwise known as vitamin D2. One might quibble that there could be differences across the two types of vitamin D used (vitamin D2 vs. vitamin D3) although I'm not an expert on the biological availability and uses of these different forms of vitamin D.

What these caveats might imply is that one study does not guidance make but one should perhaps be sceptical of any big claims made about vitamin D and CFS at the current time. CFS is of course, a very complicated condition indeed and as far as I am aware, only preliminary research forays have been made into looking at the sunshine vitamin/hormone with regards to CFS including the all-important vitamin D receptor.

No music to close the post today; just a link to the trailer for a film that my brood and I are eagerly awaiting this year... cue the rolling credits: 'A long time ago in a galaxy far, far away...."

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[1] Witham MD. et al. Effect of intermittent vitamin D3 on vascular function and symptoms in chronic fatigue syndrome - A randomised controlled trial. Nutr Metab Cardiovasc Dis. 2014 Oct 22. pii: S0939-4753(14)00315-9.

[2] Rouillon V. et al. Vitamin D insufficiency: evaluation of an oral standardized supplementation using 100,000 IU vials of cholecalciferol, depending on initial serum level of 25OH vitamin D. Joint Bone Spine. 2012 Jul;79(4):399-402.

[3] Roy S. et al. Correction of Low Vitamin D Improves Fatigue: Effect of Correction of Low Vitamin D in Fatigue Study (EViDiF Study). N Am J Med Sci. 2014 Aug;6(8):396-402.

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ResearchBlogging.org Witham MD, Adams F, McSwiggan S, Kennedy G, Kabir G, Belch JJ, & Khan F (2014). Effect of intermittent vitamin D3 on vascular function and symptoms in chronic fatigue syndrome - A randomised controlled trial. Nutrition, metabolism, and cardiovascular diseases : NMCD PMID: 25455721