Vitamin D – Current Status


   By: Dr. Jean Antoine Boodhoo

   2013-08-14 02:58 PM

1)   “Vitamin D” is a secosteroid hormone necessary for the following bodily functions:

  • It assists in the absorption of calcium and phosphorus from the gut (calcium being necessary for bones and teeth and the proper functioning of our heart, muscles, nerves and blood clotting).
  • It has a direct influence on up to 3000 genes involved in the likely prevention of some diseases such as multiple sclerosis, rheumatoid arthritis, type 1 and 2 diabetes, high blood pressure and depression. (Ref 1, 2, 3, 4)

2)    Vitamin D is primarily obtained from three sources:

  • Exposure to the ultraviolet B (UVB) rays of sunlight.
  • Certain foods such as fish (several types of salmon, snapper, trout, tuna, sardines, halibut, herring), cod liver old (Dieticians of Canada), oysters, eggs, mushrooms, fortified dairy products, fortified cereals, tofu and soy milk, salami, ham and sausages (  
  • From vitamin D supplements.

3)   The daily dose of vitamin D required ranges as follows:

The Institute of Medicine ( recommends

Infant 0 – 12 months - 400 international units (IU) or 10 micrograms (mcg)

Below age 70 - 600 IU                       

Age 70 and above - 800 IU

Recommends avoid taking more than 4000 IU daily.

Vitamin D Council ( recommends

Infants - 1000 IU daily

Adults - 5000 IU daily

The Endocrine Society ( recommends

Infants - 400 – 1000 IU daily

Adults - 1500 – 2000 IU daily

Osteoporosis Canada ( recommends

Healthy Adults ages 19 to 50 - 400 – 1000 IU daily

Under 19, at risk or 50 or over - 800 – 2000 IU daily           

With vitamin D deficiency, Dr. Jerry W. Swanson from the Mayo Clinic, recommends taking up to 50, 000 IU weekly for up to three months until Vitamin D levels become normal.  Dr. Swanson then recommends switching to a maintenance dose. (

4)   Vitamin D levels can be measured from a blood test and ranges from 50 nanomoles (nmol) per litre to 125 nmol/litre.

  • 30 nmol/L – 50 nmol/L is referred to as vitamin D insufficiency.
  • Less than 30 nmol/L results in vitamin D deficiency.
  • Greater than 125 nmol/L will contribute to risks from adverse effects.

5)   Most people are deficient in vitamin D at some time of the year. Worldwide it has been estimated that as many as 1 billion people are deficient in vitamin D.  In Canada it has been estimated that 1.1 million Canadians are deficient in vitamin D.

In one study published in the United States, 36% of otherwise healthy young adults and up to 57% of a general medical inpatient population were shown to be vitamin D deficient.  In a 2013 retrospective survey of patients admitted to the psychiatric ward of a community hospital in central Illinois, the authors found that 75% of admitted patients were shown to have vitamin D insufficiency (22.3 ng/L, with a range of 4 – 79.2 ng/L). The authors were not able to identify a causal relationship between vitamin D insufficiently and any psychiatric.

6)   Several prescription medications can contribute to impairment in the function of vitamin D including the following:

  • Anti-seizure medication such as phenytoin, valproic acid, phenobarbital, Mysoline.
  • Oral corticosteroids such as prednisone.
  • Bile acid sequestrates such as cholestyramine (Questran).
  • Weight loss medication such as Orlistat.

7)   Deficiency of Vitamin D has been associated with a number of medical and                   psychiatric problems including:

  • Alzheimer’s disease
  • Autism
  • Autoimmune disorders
  • Cancer (breast/prostate)
  • Depression
  • Diabetes
  • Chronic pain
  • Heart disease
  • Inflammatory bowel disease
  • Infertility
  • Multiple Sclerosis
  • Osteoarthritis
  • Osteoporosis
  • Rickets in children
  • Sleep disorders 

8)   Sitting in the sun for between 5 to 30 minutes two days per week, between 10:00 am and 3:00 pm can generate an adequate amount of vitamin D.  However, this can be affected by a number of factors including;

  • Season of the year (winter being worse)
  • Color of your skin (darker skin needs more UVB)
  • Amount of clouds in the sky
  • The use of sunscreen (can reduce the amount of vitamin D)
  • The region you live (geographical latitude)

Further, sitting in a sun room/conservatory does not work as UVB (the necessary component of sunshine) does not penetrate glass, and will not lead to the manufacture of vitamin D.

It has been suggested that the synthesized vitamin D in the skin may take up to 48 hours to travel to the liver.  It has been stated that scrubbing the exposed skin may wash the vitamin D off the skin.  Only wash/rinse the sun exposed areas.

9)   Indoor sun tanning beds/booths/sunlamps that generate 2% - 6% UVB (ultraviolet B) radiation have also been shown to be effective in producing vitamin D.  In this study participants used the tanning bed once a week for six months.  In a recent article it was suggested that currently the exposure time (20 minutes) of UVB radiation in tanning beds is 4.5 to 7 times the amount needed for optimal vitamin D production.

Indoor tanning has been associated with skin cancers including melanoma, squamous cell carcinoma and ocular melanoma.  Several countries have banned the use of tanning beds by people younger than 18. 

Despite the fact that the use of sun tanning beds has been increasing, it does remain a fairly controversial way of raising vitamin D. 

The FDA in the USA recently issued a proposal to reclassify UV tanning devices as moderate risk medical devices (Class II) (Skin Cancer Foundation).

10)   While the need for daily vitamin D is not in doubt, particularly in some high risk groups such as pregnancy, breast feeding women and children, there remain many controversies about vitamin D, namely;

  • There does not appear to be a clear consensus as to how much one needs to take daily.
  • It is still unclear whether vitamin D is causally related to various medical conditions as highlighted above.  Moreover, it is unclear whether supplementing can prevent many of these diseases.
  • While there is a clear relationship between indoor tanning devices and various types of skin cancers, it is still unclear whether these devices can be made safer, particularly in the face of a continued rise in the use of such devices. 

In conclusion, a daily intake of vitamin D is critical for wellness.  However, one must consult one’s health care provider when embarking on supplementation or other practices. 


1.  Video interview with Dr. John Cannell of the Vitamin D Council February 2012.\watchv=yUVb8ko6PiE&feature=player_embedded

2.  Vitamin D levels and High blood pressure – European Society of Human Genetics, Dr. Vimal Karani S, from the Institute of Child Health, University College London, London, UK (Copied from National News June 10, 2013) (

3.  Santhanakrishnan VK et al – A causal association between Vitamin D Status and Blood Pressure:  A Mendelian randamization study in up to 150, 864 Individuals.  ESHG 2013, Abstract # C18.2) 

4.  Science Daily - University of California, San Diego Health Sciences (2012 November 15) Vitamin D deficiency linked to type 1 diabetes.  (Science Daily retrieved July 20, 2013 from

5.  Ramagopalan SV, Heger A, Berlanga AJ, Mangeri NJ, Lincoln MR, Burrell A, Handundelthis, Hangel AE, Disanti G, Orton S, Watson CT, Morahan JM, Giovannoni G, Ponting CP, Ebers GC, Knight JG, A ChIP defined genome wide map of vitamin D receptor binding association with diabetes and evolution Genome Research 2010, D01:10, 1101, gr 107920.110.

6.  Tangpricha, V., Turner, A, Spina C, Decastro, S, Chen T, and Holick M (2004) – American Journal of Clinical Nutrition, 80, 1645 – 1649

7.  Lerne J, Solace M, Spencer J, and Siegel D (2005) – Journal of the American Academy of Dermatology, 53, 1038 – 1044. 

8.  Gominak S, Stumpf W, (2012) The World Epidemic of Sleep Disorders is Linked with Vitamin D Deficiencies, Medical Hypothesis, 2012, 79, 132 – 135.  (

 9.  Vitamin D The Sunshine Vitamin, Zoltan Rona, MD, MSc.

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