Monday 11 July 2022

Covid-19 & Vitamin D: A Single Case of Vitamin D "intoxication" but much misunderstanding

During the past two years much has been made of the possible but exceptionally rare dangers of Vitamin D, assertions by those who have succeeded in suppressing an official use of Vitamin D which would optimise natural defensive immunity against Covid-19. This is the opposite of media silence concerning documented dangers from the new Covid-19 vaccines (which I believe might be prevented by correcting Vitamin D deficiency).

There have been in the past occasional case reports of "hypervitaminosis D", which is an excessive blood level of Vitamin D with undesirable but easily reversible metabolic consequences. A single case of hypervitaminosis D has been documented in the UK during early July 2022. It was treated both simply and effectively. The BMJ Case Report was followed by widespread reporting in the press, far more than the incident demanded. Unintentionally the press spread disinformation due to misunderstanding, as we will see below. The initial report was in the British Medical Journal, warning doctors about possibly more cases in the future.


British Medical Journal, July 2022

The report was cascaded by several UK newspapers to alert the public. Since i published this Blog post yesterday (July 11th) I have been informed that it has also been reported in Germany and Australia. 

All the newspaper reports over-simplified the medical paper and missed the most important points.

Sky News

The Times

Daily Mirror

Evening Standard


Hypervitaminosis D

An excess of Vitamin D can lead to an increase of the blood level of calcium, which is mobilised from the bones. In turn, the high blood level of calcium (hypercalcaemia) has metabolic effects on the kidneys that increase the volume of urine production (polyuria), leading to dehydration. This is exacerbated by the other effect of vomiting. Correction of the problem is simple, by intravenous saline. 

Hypervitaminosis D is extremely rare and it has not been reported in various recent Vitamin D trials. The point is that hypervitaminosis D is always the result of errors of dose, and there is a ready explanation for this. When it occurs Vitamin D has usually been given together with calcium supplements.

Identification of VItamin D

When Vitamin D was first identified and isolated in the early 20th century, the amount of it for metabolic use was so small that it could not be "weighed". Measurement was by biological assay, and expressed as International Units (iu), an agreed international standard. One unit of Vitamin D was defined as the daily requirement of an immature ten gram (10g) mouse, the amount required to ensure its bone development without rickets.

Everyone was happy with this and Vitamin D for human use was expressed in units (strictly "iu"). 400 iu was considered to be the daily amount to prevent rickets in children, and recent consideration has been for about ten times this for optimising immunity in the human adult. The daily need can be scaled up from one unit for the 10g mouse to 6,000iu for the 60kg human, but half this would be satisfactory.

1922 – the identification of Insulin

Insulin was identified and isolated in 1922, at about the same time as Vitamin D. Similarly insulin was present in such tiny amounts that could not be weighed and so the daily need and dose were expressed as international units of biological action. The use of biological units continues to this day without any clumsy attempts to change to mass units, weights, even though the mass of insulin can be measured.

It is now known that one unit of insulin weighs 0.0347 mg, which equals 34.7 micrograms. One unit of Vitamin D weighs 0.000025 mg or  0.025 micrograms (see below). Insulin has a much greater mass than VItamin D beacuse it is a large very complex protein molecule, whereas Vitamin D is a simple oil.

It was identified that the body produces on average during each day about one unit of Insulin per hour. 24 units of Insulin per day was the initial stating dose, divided into two or three injections (8+8+8 or 16+8 units) to coincide with major meals. Insulin resistance means that increasing doses are necessary to achieve normal blood glucose levels in some people.

Imagine the confusion if people with diabetes were to be told to take 0.2776 milligrams or 277.6 micrograms of Insulin (8 units) three times a day! Chaos would be inevitable, especially as the dose must be modified to suit the individual. Diabetes specialists are sensible and keep to the units that everyone understands

Measurement of Vitamin D

One unit of Vitamin D can now be measured as 25 billionths of a gram, 0.000000025 grams, or 0.025 micrograms. This is obviously infinitessimally small, too small to see. Vitamin D can now be measured in mass units rather than biological assay units, but this has created its own problems.

As with Insulin, everyone has been happy with internationally agreed biological units, iu, of Vitamin D. The arrival of mass units (based on weight) has caused confusion and it is this that can lead to the problem of hypervitaminosis D.

The move to mass units

Whereas most doctors and the general population think of Vitamin D in terms of units, the important UK Standing Advisory Committee on Nutrition (SACN) uses mass units. Hence confusion. The same would have happened in other countries.

400 units of Vitamin D is accepted as being the minimum daily dose of Vitamin D to prevent rickets in a child. 400 units is 10 micrograms, also expressed as mcg or μg. 

Metric units

People are accustomed to using the metric unit gramme, or gram, and are aware that a milligram (mg) is a small proportion of this, but few are aware that milligram is actually one thousandth of a gram.

The microgram does not appear in the lives of most people. It is a unit of measurement effectively confined to scientific disciplines, and the scientific knowledge of the great majority of the population is abysmally low. Few people can even guess that a microgram is one thousandth of a milligram, a millionth of a gram. Such a tiny amount is beyond general comprehension. The minimum daily requirement of Vitamin D is 10 millionths of a gram (10 μg)  and the requirement for optimal immunity is 100 millionths of a gram (100 μg). Here lies the opportunity for confusion and danger.

The abbreviations mcg or μg are also unknown to most non-scientific people. Unfortunately mg can be assumed and has been expressed in the press. This immediately leads to a dose excess by a factor of one thousand.

The development of confusion

If a person takes Vitamin D 4,000 units each day, all will be well, simple and easily understood. 4,000 is a large number, but remember the 10 gram mouse.

But if we transcribe this to 100 mcg or μg there is opportunity for confusion and error. It is possible that in error 100mg will be taken, which is 4,000,000 units, a thousand-fold increase.

This is the way in which severe hypervitaminosis D can occur. Fortunately it is easy treated.

The sensible way forward is regard Vitamin D in the way that we sensibly regard Insulin: keep to well-understood international units, and forget what in practice is the pseudo-science of using tiny mass units in public life.

Advice from the Newspapers

Sky News

Sky News misinterpreted the units. Sky News reported that the subject of the case report was taking 50,000mg of vitamin D each day, which was obviously absurd. 50,000mg is 50g, the size and weight of a large egg.  but the reporter had no knowledge of units of measurement

50,000 mg is 50,000,000 micrograms, 50 million! With a Vitamin D conversion factor of 40 it would be 2,000,000,000 units, 2 billion units! How the press can misinform.

The patient, described in the British Medical Journal (BMJ)

Although maintaining anonymity, the BMJ gives information about the circumstances of the Vitamin D excess. 

"The middle-aged male patient had a variety of health issues, including tuberculosis, an inner ear tumour (left vestibular Schwannoma) that had resulted in deafness in that ear, a build-up of fluid in the brain (hydrocephalus), bacterial meningitis, and chronic sinusitis."

The description continues:

"He had been taking high doses of more than 20 over the counter supplements every day containing vitamin D 150,000 iu (daily requirement 10 mcg or 400 iu); vitamin K2 100 mg daily (daily requirement 100–300 μg); vitamin C; vitamin B9 (folate) 1,000 mg (daily requirement 400 μg); vitamin B2 (riboflavin); vitamin B6; omega-3 2,000 mg twice daily (daily requirement 200–500 mg); plus several other vitamin, mineral, nutrient and probiotic supplements."

 What we can see is vast uncontrolled polypharmacy self-administered by someone with no understanding of what he was doing. It is very sad but we are in an era of "healthism" in which taking supplements is almost routine. Those people selling the supplements should exert some control over excess consumption, and this should have been the most important message of the case report. 

In a medical world supplements, replacement therapies, are given on the basis of need. Type 1 diabetes is a condition of insulin deficiency, and insulin replacement therapy is given under controlled conditions, with careful monitoring of blood levels of glucose and HbA1c. 

Clinical and public health medicine should have a firmer grip on Vitamin D, so that supplements are given following blood level testing, with follow-up to ensure appropriate dose. Medicine is negligent in not achieving this, with public health and health service managers even more negligent in discouraging it.

Incidentally, the BMJ Case Report is not perfect. It uses both mcg   and μg as abbreviations for micrograms. My preference is the abbreviation "mcg" as this is simple to type. To type "μg" requires looking up symbols. Using Greek letters without necessity is an example of pseudo-science.

The Case Report uses IU as a cumbersome and not always intelligible abbreviation for international units. Once again we should take the lead from Insulin and use the simple abbrevation "unit" which is what everyone has used during the past hundred years.

It mentions in respect of VItamin D a "daily requirement 10 mcg or 400 iu". This is the dose that is necessary to avoid rickets, but it is increasingly recognised that about ten times that dose is necessary to optimise immunity.

When I read "Hypervitaminosis D, as the condition is formerly known...." I was rather surprised as I did not know of a more recent term. I now realise that this is a typo, and that "formerly" should have been "formally", a similar word with a very different meaning.

Blood levels of Vitamin D

The blood level of VItamin D is not generally measured, and indeed clinical doctors in the UK are discouraged from requesting it. After ingestion or production in the skin, Vitamin D is transported to the liver. It is then hydroxylated to 25(OH)D, which is the circulating reservoir available for immediate use. It is Vitamin D as 25(OH)D that is measured in the blood as a routine. 25(OH)D is also known as Calcidiol or Calcifediol. 

It is not appropriate or possible to use international units in measuring blood levels of Vitamin D. It is only since the measurement by mass units that the blood levels have been able to be expressed.

Blood levels have been initially expressed by the mass unit of nanogram

The same problem again: only people with a scientific background might understand this unit. One nanogram is a thousandth of a microgram, and so one nanogram is a thousandth of a millionth of a gram. Perhaps the general population does not need to be troubled by this.

There is a movement towards using SI units (International System of Units), involving molar measurements. And so 40ng/ml (40 nanograms per millilitre) is equivalent to 100nmol/L (100 nanomols per litre), a conversion factor of 2.5.


It is also possible to measure the blood level of circulating fully-activated Vitamin D, 1,25(OH)D. Most 1,25(OH)D (Calcitriol) is produced in the cells of immunity in response to infection, but a small amount is produced in kidney cells to circulate and act on bone and maintain an accurate blood level of ionised calcium. 1,25(OH)D is present in the blood in only very tiny amounts, measured in picograms per millilitre. A picogram is a thousandth of a nanogram, in other words a million millionths of a gram. In practical terms this need not concern us, but it demonstrates the tiny amounts of hormones that are necessary for bodily health.

Complexity can lead to error

I hope that the numbers displayed have not been overwhleming. The complexity outlined is in the use of varying terms of measurement, not of the need for and benefits from VItamin D.

I would strongly recommend the continuing use of International Units, or just "units" that we have all been accustomed to during the past century. As it works perfectly well and without confusion with Insulin, let Vitamin D be the same.

I would also recommend that doctors in clinical and public health take more responsibility for Vitamin D, identifying deficiency by blood testing, prescribing or advising appropriate dose, and using blood levels to monitor the dose of the supplement.

It is also important that pharmacists and others who are selling Vitamin D directly to the public take responsibility in advising against excessive dose and uncontrolled polypharmacy in general. 

Many strengths of Vitamin D capsules are available. Perhaps the highest strength should be 20,000 units, with emphasis that it is a convenient and effective dose to be taken only once a week. This is what I take.

On the rear of this packet, the manufacturer clearly states that this is a once per week dose, and that doctors and pharmacists must confirm this.

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