Saturday, 16 July 2011

The vitamin D-lemma

A must read news article for all of you following the vitamin D debate.

Amy Maxmen, The vitamin D-lemma. Nature 2011;475:23-25.

Some extracts to wet you appetite:
  1. A vociferous debate about vitamin-D supplementation reveals the difficulty of distilling strong advice from weak evidence.
  2. Much is at stake. By 2009, the amount spent on vitamin-D supplements in the United States had risen tenfold in ten years.
  3. "The Institute of Medicine (IOM) was too definitive in its recommendations," says Michael Holick, an endocrinologist at Boston University School of Medicine in Massachusetts, and an outspoken critic of the IOM panel's conclusions.
  4. Some physicians recommend supplementation of up to 6,000 international units (IU) a day to make up for the time that people spend indoors. This is less than the amount a fair-skinned person without sunblock might make in half an hour of exposure to the midday summer Sun.
  5. The Endocrine Society's guidelines, call people with levels under 50 nmol/L "vitamin-D deficient", and those with levels between 50 nmol/L and 72.5 nmol/L "insufficient". The society's guidelines also offer an 'ideal' level of 100–150 nmol/L for non-skeletal health benefits. 
  6. Reinhold Vieth, a vitamin-D researcher at the University of Toronto in Canada, calls this demand for huge trials "a cop-out". He says that there is good evidence that higher levels of vitamin D would reduce rates of multiple sclerosis, but a clinical trial to test this would require thousands of people and 30 years. "Saying we need perfect, placebo-controlled trials is denying the plausible evidence we have," Veith says. "At what point do you offer advice?"



"I and others have already put our heads above the parapet to offer advice on vitamin D supplementation."

"The debate regarding the IOM report and what level of supplementation is appropriate has definitely muddied the waters." 

"The IOM report is not that relevant to MS as the report was about bone health and not the immune effects of vitamin D."

"My approach to the ideal vitamin D level is is based on advice of the experts who started the Vitamin D Council and evolutionary theory." 

"Man as a species evolved as hunter-gatherers and as a result our ancestors spent much of their time outdoors. All studies to date looking at people who simulate the hunter-gather lifestyle in terms of outdoor sun exposure have levels of vitamin D well above 100 nmol/L in their blood."

"If you live in the UK (a country with poor quality sunlight) to get your levels above 100 nmol/L you need to take at 5000IU of vitamin D3 per day."

"On a personal note when my family an I started taking vitamin D supplements about 4 years ago we started on 2000IU per day. Despite this I was still deficient at the end of last winter. This is why I have now increased our level of supplementation to 5000U per day, which is in line with the Vitamin D Council's recommendations."

Other posts on this blog you may find helpful:


05 Jul 2011

Vitamin D - some facts. Vitamin D is a misnomer; it was incorrectly classified as a vitamin. Vitamins: are nutrients that are required in tiny amounts; cannot be synthesised in sufficient quantities by our bodies ...


05 Jul 2011
Vitamin D websites. You may find these websites helpful: Vitamin D Council & Vitamin D3 World CoI: Nil. Posted by Gavin Giovannoni at 09:38 · Email This BlogThis! Share to Twitter Share to Facebook Share to Google Buzz ...

09 Jul 2011
Background: This study is based on the published literature relating to the effects of vitamin D in reducing the risk of cancer, cardiovascular disease and respiratory infections (please note MS was not included in the ...

03 Dec 2010
The committee of scientists, convened by the National Academies' Institute of Medicine, doubled the upper level of vitamin D that people that people between the ages of 9 and 50 can safely take in any given day from 2000 ...

07 Feb 2010
After our MS Research Day on the 30th January we have been asked by several people about the correct dose of vitamin D to take to try and prevent MS and related disorders. Unfortunately we don't know. ...

6 comments:

  1. Prof G, is Ataxia and MS the same thing?

    ReplyDelete
  2. Re: "Is Ataxia and MS the same thing?"

    No. Ataxia is a clinical sign we detect when we observe or examine people. Ataxia refers to unsteadiness of gait or incoordination of the movements of the arms and legs. There are two main reasons why someone develops ataxia; one is when the sensory pathways that relay sensation to the brain about the position of the joints malfunction and the second is when a structure called the cerebellum is damaged. We refer to this as sensory or cerebellar ataxia.

    MS can cause both types of ataxia due to lesions in the sensory pathways and/or cerebellum. However, there is a long list of other causes ataxia, some of which are commoner than MS, e.g. acute alcohol intoxication.

    ReplyDelete
  3. In the spirit of Neurology questions... Are some TIA's treated accidentally as Stroke? TIA's may last more than the time-window for thrombolysis so could a patient theoretically come to hospital with focal neurological signs and be thrombolysed when in actual fact they had a TIA and if they had been left without treatment they could have recovered? I guess I am asking whether TIA's can mimic Stroke on CT scan... If so, surely some patients are being treated as if they have a stroke when in actual fact they could be having a TIA.

    ReplyDelete
  4. The Australian site www.overcomingmultiplesclerosis.org advises buying Vit D3 over the internet as high dose supplements are not approved there. The govenment feels they are not needed in a sunny country.

    I can't find Vit D3 in India either except in low doses bundled with calcium.

    Vit D2 Ergocalciferol is available. So is calcitriol which is a 'Vitamin D metabolite'

    ReplyDelete
  5. Re: "The govenment feels they are not needed in a sunny country."

    This not necessarily correct; with massive social change (Facebook and computer gaming generation) and use of sun blockers the incidence is increasing.

    The following paragraph is via a google search:

    "Several studies have assessed vitamin D status in Australia and New Zealand. The prevalence of deficiency varies,but is acknowledged to be much higher than previously thought. Deficiency is classified as either marginal (25OHD levels ranging from 25 to 50 nmol/L) or frank (25OHD levels, < 20–25 nmol/L). The highest rates of frank deficiency occur in dark-skinned, veiled, pregnant women (80%), with similarly high rates found in mothers of infants treated for rickets. Another high-risk group is the elderly, with marginal deficiency rates of 76% in nursing home residents, and 53% in hostel residents.18 Other studies assessing younger adults have reported marginal deficiency rates of 23% and 43%, with 8% of young women (20–39 years) found to have frank deficiency at the end of winter in Geelong (Victoria, latitude 38°S).

    http://www.mja.com.au/public/issues/177_03_050802/now10763_fm.html#elementId-1070244

    ReplyDelete
  6. Re: "Are some TIA's treated accidentally as Stroke?"

    Yes, the CT scan is done to exclude haemorrhage and very large strokes that are contra-indications to thrombolysis.

    A lot of stroke specialists believe that prolonged TIAs, are not TIAs but stroke.

    ReplyDelete

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