Thursday, 9 October 2014

Talk : Is Vitamin D the elixir of health?

Went to a talk recently about Vitamin D, but instead of being from an expert researcher (as is usually the case from organisers), it was actually from a person who was being VERY selective in the sources he chose to refer to.

For the purposes of this post, lets just call him "Pete".

Pete began by explaining a few facts about Vitamin D:
1) It is oil soluble - which means it can be stored by the body
2) It is one of only a few chemicals that all body cells have a receptor for.
3) When activated, it acts as a steroid. Its level can be measured in the blood.
4) Has an impact on the expression of over a 1000 genes (5% of the total)
5) Vitamin D exists in an unactivated form in the skin all the time - but is only activated by the action of sunlight
6) Vitamin D can be obtained from food, but at levels much lower than those from the effect of sunlight on the skin.

Pete then considered what might be the optimum levels of Vitamin D for humans and looked to Africa for the answer to this question. It seems that tribesmen (presumably living similar lifestyles to those of thousands of years ago) in Africa have a level of 50 nanograms per millilitre of blood (see here).

The highest level that Pete has seen in the UK, irrespective of skin colour, and even at the end of the summer (when levels should be highest) has been 26ng/ml - suggesting that people living in northern latitudes may be deficient in Vitamin D. Indeed, during the winter in the UK, the sunlight is so weak that the Vitamin D production process is not activated even if one were to walk around shirtless at mid-day.

This presents a problem, as excessive exposure to sunlight increases the risk of skin cancer (and even SPF8 suncream cuts down Vitamin D production by 95%) - supplements may be another route to getting adequate Vitamin D.

Pete suggested that people should get their Vitamin D blood level checked, and if they feel it is low, talk to a suitably qualified health professional to devise a programme to restore the Vitamin D level.

Regarding supplements, Pete suggested that no adverse effects were likely if one stayed at daily intakes of 5000 IU (international units) per day, with the RDA being 400 IU's

Pete stated that the body uses Vitamin D in two pathways - the first (prioritised) pathway relates to Calcium absorption. The second pathway is only activated at higher blood levels of Vitamin D (above 40ng/l) and impacts on bone mineral density, nerve health, brain health and other effects. Pete also claimed that Vitamin D was implicated in a large number of health conditions, including autism, diabetes and depression.

The Vitamin D Council was mentioned by Pete on a number of occasions as being a reputable source of information.

During the Q&A, it became clear that the audience was lucky to have some people who worked in the health sector amongst its members, and they pointed out that advice could also be obtained from sources other than the Vitamin D Council, for example the Scientific Advisory Council for Nutrition (SACN, whose report on Vitamin D can be found here(pdf)); the Nottinghamshire Area Prescribing Committee (whose protocol on Vitamin D can be found here(pdf)); and of course also at NICE (information here(pdf))

Further Information
BFTF has stumbled upon the following while researching for this post:

1) The US Institute of Medicine has investigated the health benefits of Vitamin D supplements and commented that :
"The committee assessed more than one thousand studies and reports and listened to testimony from scientists and stakeholders before making its conclusions. It reviewed a range of health outcomes, including but not limited to cancer, cardivascular disease and hypertension, diabetes and metabolic syndrome, falls, immune response, neuropsychological functioning, physical performance, pre-eclampsia and reproductive outcomes. This thorough review found that information about the health benefits beyond bone health - benefits often reported in the media - were from studies that provided often mixed and inconclusive results and could not be considered reliable."

2) Whilst the Vitamin D Council may be a "non profit" organisation, its chairman, Dr Cannell is certainly making bucks selling "Dr. Cannell's Advanced D(TM) Vitamin D Super Formula", a product that is described as:
"Formulated by the Executive Director of the Vitamin D Council, Dr. John J. Cannell, Advanced D is a next generation vitamin D complex which includes patented Super Boron, vitamin K2, zinc, and magnesium"

60 capsules for only $47 ! - although NSB suspects that this represents quite a significant mark-up.

2) This article showing how complex the issue of Vitamin D levels can be.

3) Wikipedia is, of course, a good place to start.

4) A Paper describing how Vitamin D may play a role in a number of ill health conditions

5) Perhaps what NSB found most disturbing was the way the talk was very convincing, and it was only after spending a few evenings researching that the cracks in the evidence - and the narrowness of the references - became clear. NSB has noted this down as a cautionary tale.


  1. The IoM also state that the maximum tolerable dose of vitamin d is 4000IU a day, they got this value by dividing the dose that has never been found to cause hard by 2.5. The maximum tolerable dose is a dose that can be taken without medical supervision without apparent risk. The recommended dose for a new born baby is 400IU a day (RCPCH)

  2. It is always a mistake to use secondary sources like the IoM unless you are willing to understand their criteria for what was included and what was rejected and identify the prior stance of the people involved, as you cannot avoid the effects of prior beliefs. If instead you had chosen the European Food Safety Authority "Scientific Opinion on the 'Tolerable Upper Intake Level of Vitamin D' you would have seen a much less negative opinion, probably because of a different in historical vitamin d supplementation and prior belief, as they are both considering the same data. The IoMopinion is also at least 4 years old.