Improving the health of people in the UK with Vitamin D

How much Vitamin D ?

There are 4 parts to this:

  • What do I need ?
  • What do I have already ?
  • How do I add to what I have already ?
  • What can I eat or take ?

What do I need ?

The UK Department of Health says that Deficiency is when your blood serum level of Vitamin D [ 25(OH)D) ] is less than 25 nmol/L ( nanomols per Litre )

( 25 nmol/L = 10 ng/mL ( nanograms per millilitre ) in the American scale )

The USA Institute of Medicine ( IOM ) set the equivalent level at 50 nmol/L in their report issued in November 2010

Many experts say that there are biomarkers that change just above 75 nmol/L, so they suggest that the level should be set there.

Professor Robert Heaney, who is a world expert in Osteoporosis, says that Vitamin D “enables the body to absorb calcium” and that the level should be set at 100 nmol/L

Dr John Cannell, of in his book Athlete’s Edge, says that there is “extreme substrate deprivation” below 125 nmol/L

Professor Bruce Hollis, who is a world expert in Vitamin D for pregnant women and their babies, says that the baby takes nutrients from the mother and that pregnant women should have 125 nmol/L

A group of 40 eminent experts at have issued a “Call-To-Action” calling for optimum blood serum levels to be between 100-150 nmol/L

You can watch videos about this at: or

So, you choose your expert and you set your own levels

I am following the 40 eminent experts and have set my personal target at 100-150 nmol/L

What do I have already ?

The only reliable way to know is to have a blood test for 25-hydroxyVitaminD or 25(OH)D

The options are:

  • Ask your doctor for a test.
  • Have the test done privately

Many doctors are under pressure to save the cost of testing, or they have been told that they are only allowed one test per year for each patient.

If your doctor does do a test, ask them for a copy of the result and file it carefully away for comparison with later tests.

If you want to have the test done privately there is an NHS hospital in Birmingham that offers the test direct to the public.

Check out or phone +44 (0)121 507 4278 provide a direct-to-the public testing service

You can also order a Vitamin D test at:   This is more expensive, but you are contributing your results to their database of a world-wide intervention trial.  Doctors and other health professionals who would like to enter batches of results from multiple tests done locally in their practice are invited to contact Grass Roots Health. and provide testing services, but they need a referral from a health professional, like a doctor, dietitian or qualified nutritionist.

How do I add to what I already have ?

When you have received the results of your Vitamin D blood test you will have a number that probably ranges from 10 nmol/L to 200 nmol/L, plus an opinion from the testing laboratory of how your result compares to their target.

If you compare that to the new target that you and your doctor want to set, which will hopefully be at least 75 nmol/L and could be between 100-150 nmol/L, you will probably find that there is a difference.

A rough rule of thumb is that you will need to take 25 micrograms ( = 1,000 IU ) of Vitamin D3 per day for 3 months to raise your level by 25 nmol/L.  This guide works well when you are below 100 nmol/L, but you will need increasingly large amounts above 100 nmol/L as the body self-regulates.

Here are some examples:

Result ( nmol/L )                25                    50                    25                    50

Target ( nmol/L )                75                    75                    100                 150

Requirement ( IU / day )    2,000              1,000              3,000              4,000

( Micrograms per day )       50                    25                    75                   100

I have been taking 5,000 IU ( 125 micrograms ) each day for the past 2 years and my level was 143 nmol/L when it was last tested in August 2011.

Vitamin D can be taken once a week, since the half-life of Vitamin D in the body is 14-30 days.  Multiply the daily amount by 7 and take approximately that amount once a week.


There are a very few people who have a genetic problem with Vitamin D, such as sufferers from Thyroid problems or Sarcoidosis ( too sensitive ) or Coeliac or Crohn’s disease ( not sensitive enough )  You will need detailed advice from your doctor or specialist.

The current advice for pregnant women from the NHS is to take only 10 micrograms ( 400 IU ) a day.  Please read other sections of this site and then you can be more informed to discuss this subject with your midwife, doctor or other health professional.

What can I eat or take ?

It is very difficult to get enough Vitamin D from food.  For example, you would have to eat about 300-500g of mackerel or salmon to get 25 micrograms of Vitamin D.  The best result of Vitamin D from food that I have heard of is a lady from Bangladesh who was eating 3 pieces of sun-dried fish from Bangladesh each day.

The other alternative is to expose your body, without sunscreen, to direct sunlight – but only when your shadow is shorter than your height.  This is only possible in the UK between April and September between about 10:00am and 4:00pm.  Do not burn your body and cover up if your body begins to become pink.  A white skinned person will receive 20,000 IU within 15 minutes, but an Asian person might need 30-60 minutes and an African person might need 1-2 hours in the direct sun.

In his book Athlete’s Edge, Dr John Cannell of  describes how his daughter has fair skin and used to burn easily.  He suggested that she took 10,000 IU of Vitamin D3 a day for a month before she went into the sun, and she then found that she was not as sensitive to the sun as she used to be.

You can buy 25 micrograms ( 1,000 IU ) of Vitamin D3 over-the-counter from a chemist or supermarket.

You can buy anything from 1,000 IU to 10,000 IU from most Health Stores or online from eBay, Amazon or other specialist supplier of Vitamins and supplements.

You can take tablets, capsules, sprays or drops.

Doctors can prescribe 500 micrograms ( 20,000 IU ) of Vitamin D3 for weekly use, but these are “specials” which may cause problems in sourcing or payment via the NHS.

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5 Responses

  1. Last year I did a little experiment where I wanted to see how high I could get my Vit D levels upto just by being out in the sun for a month. So Aug ’12 I spent most of the time working on my laptop outside with my top off a few miles North of Cambridge, England hitting the shade at the hottest times to avoid burning.

    Some basics, Skin Type 3, had already built up a nice tan (natures sun screen) which it should be noted melanin converts 99.9% of UV radiation into Heat “Melanin is an effective absorber of light; the pigment is able to dissipate over 99.9% of absorbed UV radiation.” Wiki has been changed, originally it stated it converted it into heat.

    I had already supplemented on D3 so my levels stood at over 100nmol/L based on my last NHS Vit D spot test.
    Anyway after Aug, got another Vit D spot test done and it had reached 229 nmol/L just from being outside which goes against the 105nmol/L global avg which is currently being suggested as the optimum by some medical professionals based on the studies carried out on humans who live on the equator like the masai warriors who spend a lot of time in their mud huts and daubing themselves with paints of sorts thus helping to avoid the sun!

    I did spend some time in the hottub during that month of Aug which was filled with Epsom Salts, Magnesium Chloride and Dead Sea salts (no chlorine or other chems) but overall avoided getting any water on the bulk of my trunk by forgoing daily showers and sticking to washing pits, groin & feet to test the 1937 study theory which seems to be true.

    I’m currently testing another theory of mine which is high Vit A, D & K is very good for us.

    I currently stand at 235nmol/L (Test sample 6th Nov,13) to see what the hypercalcemic effects would be like ie could I feel bone aches or anything else, but what should be noted is I use highly concentrated Mag Oil (magnesium chloride & water) after showering to get magnesium into the body which gives a “Deep Heat” like muscle relaxant effect and before sleep. I also consume 2-4kgs a week of Brussel Sprouts, Broccoli & Kale plus plenty of herbs like Basil & Parsley to increase the Vit K levels in my diet, much like what one might find in an Elizabethan Cottage garden which would have been before cultivated crops or medicine as we know them today. I have no wind problem as many seem to think, the good bacteria in the gut needs plenty of greens and as it adapts, so your gut may produce some wind to begin with but that will go, but also avoid carbonated drinks. CO2 like most gases used in operations including gastric will distor the gut allowing for food to enter different parts of the gut more quickly than it should. Some surgeons have questioned why they cant use CO2 as it causes the least gut discomfort compared to what they have to use in the NHS operating theatres, but fizzy drinks especially CO2 do not aid disgestion it hinders it.

    My theory goes like this, higher Vit D levels causes the body to increase the amount of calcium the body takes up from the diet (not bones I have been advised) which shows up as higher calcium in the blood leading to hypercalcemia when Vit D3 is around 500nmol/L or more. So with all this calcium flowing through my blood so to speak, what else could I do to get it to go to my bones? Cue, Vit K. The Japanese licence 45mg of Vit K2, MK4 to treat bone loss in postmenopausal women.
    Now I’m not a postmenopausal woman but if the Vit K has that effect its worth investigating. Well it turns out the body converts Vit K into different ratios and sub groups like Mk4 and the nett effect is, if eaten in high enough quantities, the Vit K can increase oestoblast (bone builders) and reduce oesteoclasts (bone cleavers or destroyers) plus other benefits for the body like better gut bacteria and thus digestion. So I’m seeing what effects I can observe by getting upto a hypercalcemic level of Vit D, with high Vit K and the mag oil. It should be noted the more bitter tasting some greens are the higher the Vit K content. Dandelion leaves are very bitter and high in Vit K as one example of a common weed which is actually very healthy for us and used to be consumed regularly in Elizabethan times.

    Its also worth mentioning when a child or teenager breaks a bone, their body goes hypercalcemic anyway, so maybe getting the body into a hypercalcemic state with plenty of Vit K may actually have a rejuvenating effect because calcium is also very alkaline and most diseases and illness make the body acidic, hence hypercalcemia may help the body maintain its natural or optimum ph balance as well. Who knows its early days, but I dont think Vit D derived hypercalcemia should be seen as a bad thing considering the lengthening of the telemores either, but there does need to be plenty of Vit K imo. The Vit A also have uses on its own but also greater benefits when in combination Vit D, this is also mentioned on the site a very useful site if you have the time to go through all the articles like I have.

    On the point of supplementing, a recent Finnish (I believe) study showed some supplements only contain 17% of the Vit D3 stated on the packaging and others could be as high as 146% over what is stated on the packaging, a job for Trading Standards if ever there was one.

    So my advice is to test 4 times a year, because D3 has a half life of around 28days which means every 28days it will reduce by half if you stop supplementing plus you body will take what it can use so if you are particularly ill your body may need more than someone else. Thats why I dont really recommend any given amount to take, test is best, but if people dont test and start noticing bone aches, stop taking the D3 supplements for a few days or weeks and increase your intake of greens or other foods high in Vit K like unpastuerised mature hard cheese, or Natto. Some unpasteurised fermentated foods like Natto & cheese can be high in Vit K.

    A little about my diet, its paleo, basically meat, veg & fruit, I dont eat carbs or foods which are poisonous if eaten raw like spuds. I try to avoid sugar where possible as a single can of fizzy pop can reduce testosterone by 25% within 2hours which I dont want either, I tend to have a cooked breakfast every day consisting of 2 eggs, 2 smoked back rashers of bacon and 2 sausages, then nuts & fruits throughout the day, then tend to have a meat and greens, carrots & peas for evening meal. I love my roasts, but I roast all the veg alongside the meat in copious amounts of oil, I tend not to boil veg if I can help it.

    I have to say I have never been slimmer, I eat until I feel full none of this weighing stuff and have lost 4 inches around my waist so I’m now slimmer than when I was 18 years old (over 20years ago) and I can still pig out when I want, but have to confess I no longer have a craving for anything sweet or unhealthy.

    I do love plenty of double cream on fruit though and I sit on my backside writing computer programs most of the time (12hrs + a day 7 days a week) so it just goes to show you dont need to be a gym bunny to get in shape and have reasonable muscle definition.

    Anyway thats my experience and thoughts of the levels of Vit D just to inject some anecdotal evidence into the debate of what is the right amount of Vit D to have. 🙂

  2. The article adds value in highlighting the importance of physiological vitamin D concentration in reducing complications form a verity of diseases, including COVID-19. Nevertheless, being too conservative, many such articles continues to recommend too little daily vitamin D doses tot the public. Levels such a below 1,000 IU will take months or even years to raise serum 25(OH)D concentrations to adequate concentrations. Therefore, worthless during any urgent situation like COVID-19 and for those with comorbidities, to raise individual and the population 25(OH)D concentrations to protective physiological concentrations of above 30 ng/mL. Especially during annual winter epidemics of respiratory viral infections and the current COVID-19 pandemic.

    Most, adequately powered, well-designed clinical studies conducted on persons with serum 25(OH)D concentration less than 20 ng/mL (consist of virtually, in more than 95% of persons severely affected with COVID and related deaths), administration of daily doses between 4,000 and 6,000 IU is necessary to raise and maintain serum 25(OH)D concentration above 40 ng/mL to stimulate the innate immune system and to provide optimal protection.

    This can also achievable by taking 50,000 (or 60,000 capsules in some countries) weekly or every other week depending on comorbidities and the need and baseline serum 25(OH)D concentration. However, in urgent situations, upfront loading doses between 100,000 and 600,000 IU would be appropriate, to be followed by a mentioned daily maintenance dose to overcome COVID-19 and associated complications and deaths.

    Sunil J WImalawansa, MD, PhD, MBA, DSc.
    Professor of Medicine, Endocrinology & Nutrition

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