Vitamin D is a Steroid vitamin.  This means that it is “fat soluble” and that it does not really dissolve in water.

Therefore, to absorb Vitamin D, you would be well advised to have it during the highest fat content meal of the day – usually supper.  Having your Vitamin D Supplement with the “fattiest” meal of the day will increase your absorption of the Vitamin by as much as 50%!

There are 5 forms of Vitamin D: D1, D2, D3, D4 and D5.  Only D2 and D3 really matter to humans. It is almost impossible to get Vitamin D “naturally” from your diet. Your body has to make it – and to “activate” Vitamin D, it has to be exposed to sunlight in your skin.

Your skin make enough Vitamin D for the day after about 15 minutes of sunlight exposure. People with darkly pigmented skin need more sunlight exposure to generate the same amount of Vitamin D. This may be one reason that folks with darker skin have an increased incidence of prostate cancer.

It has been shown in the literature that moderate to high levels of vitamin D intake can reduce the risk of heart attacks – although the jury is still out on this one because it is difficult to test across the spectrum of cultures and environments in which we all live.

Observational studies have revealed that low Vitamin D levels are associated with Multiple Sclerosis, Cardiovascular Disease, Certain Cancers, Juvenile Diabetes, Parkinson’s Disease, Depression and Alzheimer’s Disease. So far, however, adequate scientific studies have not proven that taking Vitamin D Supplements can reduce the risks of developing these conditions.

It has also recently been found that good levels of Vitamin D in the blood at the start of a weight loss program, is predictive of weight loss success.

So what are we to do?

We have to stick with what we know. we DO KNOW that low Vitamin D levels are associated with those conditions above. Therefore, it would appear to follow that having a “normal” or “acceptable” Vitamin D level would remove you from at least one association with those diseases.

We also know that taking up to 1000-2000 IU per day of Vitamin D poses no risks or concerns to your health. So – while we are waiting for proper scientific studies to solve these questions – it seems reasonable to take Vitamin D to supplement our often inadequate serum levels of this Vitamin.

More information about Vitamin D:

At Boston University, after people with high blood pressure were exposed to UVA and UVB rays for three months, their vitamin D levels increased by more than 100% — and more impressively, their high blood pressure normalized. One theory about how vitamin D reduces blood pressure: It decreases the production of a hormone called renin, which is believed to play a role in hypertension.

In a study published in the Journal of the American Medical Association in December 2003, of more than 3,000 veterans (ages 50 to 75) at 13 Veterans Affairs medical centers, those who consumed more than 645 IU of vitamin D a day along with more than 4 grams per day of cereal fiber had a 40% reduction in their risk of developing precancerous colon polyps.

In a report in the Journal of the American Geriatrics Society in February 2004, researchers at the University of Basel in Switzerland showed that elderly women who took a vitamin D supplement plus calcium for three months reduced their risk of falling by 49% compared with consuming calcium alone. Those women who had fallen repeatedly in the past seemed to gain the most benefit from vitamin D.

A study published in the Jan. 13, 2004 issue of Neurology indicated that women who get at least 400 international units of Vitamin D are 40% less likely to develop multiple sclerosis compared with those not taking over-the-counter supplements.

The research is ongoing – and it will be interesting to see where it takes us. Clearly nothing in terms of how Vitamin D is used by our bodies is simple – but in the mean time we have to stick with what we know: Vitamin D is potentially really good for us, and doses in the 1000 – 2000 IU per day range are totally harmless.

Vitamin D – What you need to know

Dr. John Fernandes

B.Sc., M.Sc., M.D., LMCC, CCFP, FCPC Clinical Lecturer, University of Calgary I am a Physician with over a decade of experience in my own Private Clinic as well as a full admitting Physician to a Tertiary Care Hospital in Calgary. Married with two daughters that both want to be Physicians as well. Hobbies include skiing, golf, mountain biking and Karate.

3 thoughts on “Vitamin D – What you need to know

  • March 1, 2013 at 10:12 PM

    Would you mind commenting on the difference(s) between D3 taken in liquid form vs pill form?

    • March 2, 2013 at 12:51 AM

      Certainly! This is a GREAT question!

      Basically, Vitamin D is a fat soluble vitamin, just like the other three (A, E and K). Therefore, Vitamin D does NOT dissolve in water… ONLY dissolves in oil or fat. This is why it is BEST to take Vitamin D with the fattiest meal of the day, which is usually supper – but sometimes breakfast. Egg yolks, for example, contain LOTS of fat that will help to dissolve Vitamin D so that it is better absorbed by your gastrointestinal tract.

      Here’s the thing: Most bottles of “liquid” vitamin D are NOT oil or fat….they are WATER BASED! This allows the manufacturers to dissolve other things like sugars, flavourings and colourings into the solution to make this type of vitamin D palatable. The Vitamin D that is in a water-based liquid preparation is usually a modified form of Vitamin D that allows the Vitamin D to dissolve in the water-based substance (which is NOT NORMAL for Vitamin D3). The additional flavourings, colourings and sweeteners that are put into the “liquid” to make that form of Vitamin D more palatable – actually IMPAIR the absorption of Vitamin D3 by your Gastrointestinal tract. More often than not, the sweeteners are artificial sweeteners – which are not necessarily a healthy food choice for something that is taken regularly.

      The only “real” source of liquid vitamin D is the dreaded “Cod liver oil” that your grandma gave to one of your parents. They probably still have nightmares about it.

      It was interesting to note that the head of Canada’s Osteoporosis Society mentioned to me at a Continuing Medical Education Event recently, that the regular “liquid” Vitamin D supplements appear to not work very well at all. Vitamin D is MUCH better absorbed by your Gastrointestinal Tract in “pill form” – which is to say that the Vitamin D is rendered into a “salt” that is compressed into crystals – that dissolve into any fats that you have in your Gastrointestinal Tract at the same time that you take your Vitamin D3. This is why it is best to take it with the fattiest meal of the day (usually breakfast or supper). We recommend folks to take our JP Vitale with either breakfast or supper…..and BOTH when under a lot of stress.

      Hope that helps!


    • April 22, 2013 at 6:29 AM

      Certainly! Vitamin D in a liquid form has usually been altered slightly in order to be able to dissolve it in water. If the liquid form is some sort of oil, then you are really getting true Vitamin D3. Studies have shown, however, that the body absorbs Vitamin D best from a simply solid pill or capsule form. Does that help?


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