The Sunshine Vitamin D

As part of my Nutritional Therapy course I had to complete a scientific review of current research on the impact a single nutrient might have on a specific disease.   I chose Vitamin D and Osteoporosis [OP].  I wanted to answer the question ‘does current research show that adequate levels of Vitamin D have a positive impact on OP’?   Turns out that it does!   Not surprising I hear you say!  Most of us already know from TV commercials that Vitamin D is necessary for healthy bones and to absorb calcium.  But how much is adequate?   I discovered there are many and widely differing opinions on this and just when I thought I had this bit figured out, I learned that no vitamin works in isolation in the body anyway.   Plus, there are so many factors other than nutrients involved in disease progression.   I found out Vitamin D is not even a vitamin really!   It was designated a ‘vitamin’ based on its role as a dietary factor that aided in the cure of rickets.  It is now understood to be more ‘hormone like’ in its action.   Did you know, it is difficult to get adequate Vitamin D through diet alone?  Vitamin D is not even required in the diet if there is sufficient sunlight to allow its production from pro-Vitamin D molecules in the skin.  It is made in the body with its own Vitamin D receptors [VDRs].  For this reason it could be classified as a hormone rather than a vitamin (a vital amine).  Vitamin D deficiency is a worldwide epidemic across all ages, genders and geographic locations with multiple implications on human health, due to its role in various bodily systems.   Even if you can avail of adequate year round sun-exposure on bare skin, the time of day, the colour of your skin and your age will also influence how much Vitamin D your body can produce.   A Nutritional Therapist seldom recommends a single vitamin but Vitamin D could be the exception to that rule, though it requires magnesium to be absorbed property and works in synergy with Vitamin K2.  Deficiency of Vitamin D has an impact on so many body systems yet symptoms of deficiency are not very obvious.  The only way to really know if you are deficient is to take a 25(OH)D blood test.   Are you getting enough of the ‘Sunshine’ Vitamin?  Let me help you figure it out!

What are the food sources of Vitamin D?

Vitamin D is a fat soluble vitamin that is stored in the body and used up as required.  Food sources include wild caught salmon, mackerel, tuna, sardines, caviar, eggs and beef liver.   If you are not a meat eater then you can get a small amount of Vitamin D from mushrooms and also nut milks and fortified cereals [check the label for amounts].  Q: Are you regularly consuming any of these foods?

How much sun exposure is enough?

I was fascinated doing the research to discover that from an evolutionary point of view, your skin colour is directly related to the production of Vitamin D.  Long story short, before the worlds continents started splitting apart and moving away from the equator, we humans were getting plenty of sun and our dark skin protected us from its burning rays.  The further away we moved, the lighter our skin colour became so that we could make more Vitamin D with less sun exposure.  How clever!!  Countries further than 37o north or south of the equator don’t get enough year round sun and inhabitants are at greater risk of deficiency.  Ireland is 53 degree north.   If you are fair skinned you only need to expose your body to sunlight for 5-15 minutes per day a few times per week to produce adequate Vitamin D.  If your skin is black you may need to stay out six times longer for the same effect.  Also, it is just the UVB rays of the sun that create this process in the skin.  UVB rays only shine between 10am – 3pm with the best time around noon to 1pm.   Even the Irish cancer society recommends availing of this limited sun exposure for your health – click here.   Outside of these times, regardless of how much sun you are getting, your body is NOT making vitamin D.   Also, during this time of day if it is cloudy, if you are covered with clothes, behind a window or wearing sunblock – you are not producing Vitamin D.   I have not seen this happen in a long time  but when I was young it was not unusual on a sunny day to see disembodies arms of city office workers stuck out of open windows trying to catch some of those rare sunny rays.   I doubt that they were thinking ‘must top up my vitamin D levels’ ♥  Q: So, do you think you are getting enough sun exposure to make Vitamin D?

Who is most at risk of deficiency?

Almost everybody is at risk unless you are living below 37o from the equator AND are getting plenty of year round outdoor ‘exposure’ to UVB rays, eating lots of oily fish or supplementing with Vitamin D.  Your risk increases further if you are an infant (50% of babies are vitamin D deficient), a child, elderly, obese, if you have dark skin and/or spend your time indoors.   There are many other physical, dietary, medicinal and lifestyle factors that can negatively impact levels of Vitamin D in your body.  There is only one way to know for sure if you are deficient and that is to take a blood test.  Vitamin D status can be measured as serum 25(OH) D and most experts agree with the following categories:

Deficient < 20 ng/mL   Or  < 50 nmol/L
Insufficient 21-29 ng/mL Or  50-75 nmol/L
Normal ≥ 30 ng/mL   Or   ≥ 75 nmol/L
Optimal 50 ng/mL Or 125 nmol/L

Fear of toxicity is often cited by medical practitioners prescribing Vitamin D as it is a fat soluble vitamin which can be stored and therefore can build up in the body.   However, toxicity is extremely rare and deficiency is extremely common.  It is worthy of note here that lifeguards exposed to a lot of sun have reported serum 25(OH)D levels of 100-125 ng/mL (250 nmol/L and above) naturally from the sun but this is considered excessive in the general population.

Why you should make sure you have enough Vitamin D?

Traditionally Vitamin D has been associated with bone health but in recent decades science has revealed many more of its vital functions in the body.  Vitamin D receptors are found in nearly every tissue and cell of the body.   It has been found to have a significant impact on around 230 genes including those associated with diseases like multiple sclerosis, diabetes, Crohns and other autoimmune diseases.  Here are some of the proven benefits of adequate levels of Vitamin D.

Source: Google Images 
How much should you take?

Firstly, and just to complicate things, it is important to know that there are two measurements mg or mcg (micrograms) and IU (international units) of Vitamin D.  If you are taking a Vitamin D supplement or fortified food you may see the dose described in either or both of these ways.   For example, a supplement has 2,500 IU or 62.5mg of Vitamin D3. The calculation for Vitamin D is 1 IU is the biological equivalent of 0.025 mcg.   Secondly, how much you need to take depends on your level of deficiency and this should really be checked with a blood test.   It is difficult to generalize dosage with this vitamin and research indicates that anywhere between 400IU up to 10,000IU is appropriate depending on deficiency state and stage of life etc.  Dr. Michael F. Holick is a world leading expert on Vitamin D.  Click here for a link to his website and go to D-tables to discover the recommendation appropriate to you. Ultimately, what you want to achieve is optimum blood levels of Vitamin D above 75nmol/L to 125nmol/L.  Of course, this means if you test deficient and take a supplement for a while, you may need to re-check to know your improved status and then just take a maintenance dose if sun or dietary sources are low.  With no other sources a safe dose would be 38 mcg or 1520 IU for the summer months and twice this for the winter months but this may not be enough if you are deficient.

The body stores Vitamin D but if un-replenished it would take only ten weeks for this store to be used up.  The positive side of a stored vitamin is that you can take a weekly dose, though more recent research seems to indicate that a daily dose works best.  The way to take different vitamins varies, for example, Vitamin C is water soluble and cannot be stored or made by the body but is easily obtained from the diet.  Intake is therefore vital (it truly is a vitamin) and best practice is to take small amounts often throughout the day.

The take away message here is if your blood shows less than optimum levels of Vitamin D, then extra supplementation is good and desirable, but when you have reached ‘optimum’ there is no additional health benefits to taking copious amounts of vitamin D.

Supplement quality is really important!

I have no vested interest in promoting any particular supplement range, this blog is based only on my own experience and knowledge.   The rule of thumb with most supplements is, if its really cheap or ‘big brand’ it is probably not good quality.  You may just be wasting your money – at best!  You need to look at the ingredients, how much of the vitamin your buying, are you getting?   Compare!  Supplements can contain fillers especially when in tablet form, so look at ingredients.  You can get Vitamin D in drops (liquid) this makes it easy to take and is easily absorbed.  Vitamin D can also come in a sealed capsule containing oil.  ‘Viridian’ is a clean brand that is available in Irish health stores. Good on-line companies that I am familiar with are  Cytoplan, NutriAdvanced Ireland, Pure and Natural Ireland and Biocare whose products you get through ‘The Natural Medicine Company  – link here.   You can also buy multivitamins with a maintenance dose of Vitamin D (around 40mcg).   Nordic Naturals have good quality cod liver oil (Vitamin D & A).  Remember, I told you this – when you get to the health shop the sales assistant will not know exactly how much Vitamin D ‘YOU’ need to take.

When diet, sun exposure and supplements are not an option there is yet another way to make Vitamin D according to Markito Nutrition.  I watched a half hour video on YouTube called ‘The Truth about Vitamin D’.  Watch it here.  Using a UVB sun lamp to make your own vitamin D is presented as another option.    I don’t know how viable that is for most people but you might like to check it out.

Where can you get a 25 (OH)D test?

You could ask your GP/Nurse to do it…  I say that with some reservation.  Unless your GP has a reason to request a Vitamin D test based on his/her own diagnosis, they usually do not agree to test just because you asked.  But you could ask anyway.  Fitzwilliam Food Test in Dublin city will do the test for €65.   You can also order a test kit on-line from Let’s Get Checked  link here .

Remember that the test is called the 25-hydroxoyvitamin D, or 25(OH)D.  Some other types of Vitamin D tests can show normal or even elevated levels of Vitamin D, which are actually inaccurate and can hide a serious deficiency.  I recently took a Vitamin D test myself and the result came out at 53.9 nmol/L, so I’m in the ‘insufficient’ range.  The theory is that 40IUs will raise blood levels 1 nmol/L.  So to get it to optimal range I would need to take an additional 1000IUs for 12 weeks.  The good news is that, as supplements go, Vitamin D3 is not expensive.  The thing is though you really need to get tested again to be sure.

What is the benefit of knowing your Vitamin D status?

More and more research is coming to light about the benefits of the ‘sunshine’ vitamin.   There is increasing evidence of a link between deficiency and chronic pain (Fibromyalgia), low mood (Depression), cognitive decline (Alzheimer’s), and other muscular, nervous and autoimmune diseases.  Vitamin D is needed to absorb calcium and phosphorus and to regulate other nutrients in the body.  It benefits your thyroid, brain, hearing, digestion and helps regulate your immune system to defend against infection and viruses.  If you are still not convinced by the science just imagine for a moment how you would feel if you took yourself off on a sun holiday in the middle of our dark cold winter.  Your body, mind and spirit respond positively to sun exposure.  Looks like mother-nature put that response right there so that we would go with it and soak up some of those ‘feel good’ rays of the sun that nourish our bodies and minds.   Alas, we are often hampered in this pursuit by our busy, clothed, skin protected and indoor modern lives.

If you add up the cost of testing and supplementing with Vitamin D it is relatively inexpensive compared to the cost deficiency could cause to your health and well being in the long term.   We all need multi vitamins and a variety of plant nutrients, most of which we can get in a healthy diet containing a rainbow of coloured vegetables and fruits.  Vitamin D…. not so much!   Sadly, in the normal run of things you may only be offered a Vitamin D test if you are already in the jaws of a suspected disease state – why not take control of your own health??  You have the power to do this for yourself.

We have had more sun than usual this May and June 2018 in Ireland.  Q: Did you catch a few rays?    I hope you found this blog useful.


  • Dr. Michael Holick  (link above)
  • The Vitamin D Council  at []
  • Haas, Elson, M. ‘Staying Healthy with Nutrition’
  • Galloway, S. ‘The Diagnosis and Treatment of Common Functional Illnesses’
  • The Irish Cancer Society (link above)

© AOS2018

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.