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Vitamin D

Vitamin D: How to Determine Your Optimal Dose

Wednesday, October 28, 2009 by: Dr. David Rostollan, ND
Tags: vitamin D, health news, Natural News

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(NewsTarget) In the wide world of supplements, vitamin D is the superstar. For the last few years, this humble nutrient has been featured prominently in allopathic and alternative circles alike. It has basked in the rays of media publicity, and has survived an onslaught of scientific scrutiny. And while such widespread publicity is often good cause for skepticism in the realm of health and medicine, vitamin D appears to be the real deal. Whether we`re talking about heart disease, cancer, diabetes, multiple sclerosis, or Alzheimer`s disease, the "sunshine vitamin" delivers benefits unseen before our time (1).

Given the remarkably powerful benefits of vitamin D, many find themselves wondering how to actually go about obtaining it. We know that vitamin D is good for us, but how much do we need, and where do we get it? Most people know that sunlight is somehow involved in vitamin D production, but is sunlight alone sufficient to produce the incredible results demonstrated by recent vitamin D research? What about supplements? There are so many different preparations - with doses ranging from 400 IU to 50,000 IU - that it can get a little confusing. Are such supplements necessary, and if so, how much should we be taking?

Everyone is Different

One might suppose that this question is as easily answered as saying, "Everyone needs to spend 15 minutes in the sun every day." Or, "Everyone needs to take x amount of vitamin D per day." But it`s not like that. Not at all. There are a multitude of variables unique to you that determine how much vitamin D is required on a daily basis (2). And because there are so many individual variables, it really is impossible to recommend a single amount for everyone. Fortunately, however, there are many circumstantial clues to look for that will suggest whether you need to be paying better attention to your vitamin D status. Furthermore, personally optimizing your vitamin D level is fairly easy and inexpensive.

Are you at risk for vitamin D deficiency?

-How much sun exposure do you get every day?
-Where do you live? Above or below the 35 N latitude line? (3)
-What is your age? Over 40?
-Is your skin light, dark, very dark?
-Are you overweight?
-Do you have a chronic illness?

How do each of these factors affect vitamin D status?

Sun Exposure: Catching some rays each day is definitely desirable, and healthy young people can usually get the vitamin D they need from around 10 to 30 minutes of sun exposure per day - depending on their location and the time of year. Most adults in today`s modern world, however, do not even attempt to get this much sun exposure - much less achieve it. But even if they did, would it matter, or are there other variables standing in the way?

Location: Vitamin D is produced in the skin from a cholesterol derivative when we are exposed to UVB radiation from the sun. However, because of the axial tilt of the earth, the further north one lives, the less the sun`s UVB rays will be able to activate vitamin D in the skin. So sun exposure does not necessarily equal optimal vitamin D status if you`re living in the wrong location. Living down south is better, of course (south of the 35 N latitude line seems to be the best), but there is still more to consider.

Age: Say you do live close to the equator, or are significantly below the 35 N latitude line. That`s a good thing, and it probably helps. If you`re around 35-40 years old or above, however, you`re likely losing the ability to activate sufficient levels of vitamin D in your skin, even in the unlikely event that you`re getting adequate UVB sun exposure (4).

Dark Skin: What if you have dark skin? If you have a lot of pigment in your skin, this is going to shield you from the UVB radiation you need, and you`re probably deficient in vitamin D.

Weight: Vitamin D requirements are also relative to body weight. If you`re overweight, your body requires more vitamin D than if you are not overweight. If you get a lot of sun, but are on the heavy side, you`re probably still not getting enough vitamin D.

Chronic Illness: Chronically ill? Have cancer? The body demands more vitamin D when you`re sick, and is probably using it up faster than you can get it from the sun.

When one considers that many Americans are victims of not just one but many of the above drawbacks, it becomes readily obvious as to why there is such a widespread vitamin D deficiency epidemic. Not getting enough sun is bad enough, but lack of sun exposure combined with being middle-aged, overweight, and chronically ill is an absolute disaster - and it is the devastating situation that many (most?) Americans find themselves in today.

Is Sun Exposure Really Not Enough?

Yes, sun exposure is a good thing, but too often, it`s simply not sufficient to achieve the kind of levels necessary for disease prevention and treatment. This applies even in places like Hawaii, where individuals get plenty of sun exposure, and the latitude is around 21 (5, 6). The role of sunlight should not be downplayed too much, however. If you`re healthy, young, and live in a subtropical region, then you might have sufficient vitamin D levels. In fact, some young people in the subtropics who get sun exposure all day long have levels between 80-100 ng/ml. This is incredible, and it means that sun exposure really does work provided the conditions are right.*

The point being made in this article is simply that not everyone is young, not everyone is healthy, not everyone lives in Houston, and not everyone gets enough sun exposure every day. It is those people who need to supplement with vitamin D. This also happens to be most people.

Blood Testing is Crucial

How do you know if you`re getting enough vitamin D, and how much is enough? The only way to know is by testing your blood. Fortunately, testing vitamin D, as far as blood testing goes, is pretty cheap. You can set this up with your doctor, order tests online and get blood drawn at a local lab, or order a vitamin D home test kit, whereby you simply order the test, prick your finger, send in the blood, and wait for the results to come back to you.

Here are some basic guidelines:

-Make sure you are getting the right test. You must test for 25(OH)D, not 1,25(OH)D. They look similar, but 1,25(OH)D is a measure of kidney function, and is not the test you want for measuring vitamin D levels.

-Ideally, your blood level should be around 60-80 ng/ml, as this allows the body to have some vitamin D in reserve, and it duplicates the higher levels found in young, healthy individuals who spend a decent amount of time in a sun-rich environment.

-Begin taking vitamin D at least eight weeks prior to being tested. This will help you customize your dose once you receive your test results. To determine a basic, starting dose, it has been suggested, as per Dr. John Cannell of the Vitamin D Council (7), that you take 1,000 IU per 25 pounds of body weight. A person who weighs 150 pounds, for instance, would take 6,000 IU per day as a starting dose (150/25 = 6. 1,000 x 6 = 6,000). Do this for at least eight weeks, and then test. Perhaps this dose will put you in the ideal range, but there`s no guarantee since we are all so different, and have unique vitamin D receptor genotypes. The idea is to hopefully get somewhere in the ballpark with this method and then tweak your daily dose once the test results come back. If your results are still suboptimal, Dr. Cannell has estimated that each 1,000 IU increase in supplemental vitamin D will generally produce a 10 ng/ml increase in the vitamin D blood level (8). For example, if you have been taking 5,000 IU per day for 8+ weeks, and your results come back at 40 ng/ml, you would want to increase your dose to at least 7,000 IU (2,000 IU = ~20 ng/ml rise in blood level) to achieve a minimum of 60 ng/ml. Again, keep in mind that this is necessarily generalized, and additional blood testing every several months is recommended to further customize the dose appropriate to you.

What Kind of Supplements Should I Use?

In order to achieve consistent and predictable results, it is important to use the proper carrier form of vitamin D supplements. The absolute best form is an oil-based vitamin D preparation. Dry preparations, like tablets and capsules, should be avoided. Vitamin D is fat soluble, and needs to be taken with fat in order to be properly absorbed - hence the oil-based recommendation.

Oil-based versus dry preparations aside, there are two common types of vitamin D: Vitamin D3 (cholecalciferol) and Vitamin D2 (ergocalciferol). You will need to avoid supplementing with vitamin D2 (9), which is a synthetic product made by exposing certain plants to ultraviolet radiation. D2 is not what the human body naturally uses, and compared to D3 it falls far short in terms of efficacy (of course, D2 happens to be what many vitamin D prescriptions are made of). D3 is what your body uses and prefers. No prescription necessary.

You can buy D3 in oil-based softgels, or, if you don`t like taking pills or have trouble doing so, you can get it in liquid drops.**


Vitamin D status is important year around, but whenever fall and winter are upon us, the importance of evaluating this vital nutrient is even more urgent. In summary, here are the steps you should take if you are wanting to optimize your vitamin D level:

1) Start taking oil-based vitamin D3 according to your body weight, as explained above.

2) After at least 8 weeks, have your blood tested by a good lab. There are home finger-prick test kits that are also very good.

3) Remembering that the goal should be blood levels of 60-80 ng/ml of 25(OH)D, adjust your vitamin D3 dose to achieve this level. Each 1,000 IU increase will generally lead to a 10 ng/ml increase in blood levels.

4) Recheck blood levels every several months to make sure you are still in the optimal range and taking the proper dose.

*It is beyond ironic that for quite some time now, everyone has been encouraged by the "authorities" to avoid the sun in order to keep from getting cancer, yet it is that very sun exposure that would help in avoiding cancer in the first place! "Avoid midday sun, or you`ll get melanoma!" we`re told. But melanoma is mostly triggered by UVA rays from the sun - not UVB. When is cancer-causing UVA exposure the lowest? Right around midday. When is UVB exposure the highest? Also right around midday. A high UVB:UVA ratio (high UVB and low UVA) is the best for creating vitamin D in the body, and this occurs when the sun is highest in the sky - exactly the time (ironically) that is often suggested to be avoided.

**Supplementation is not recommended for everyone. Certain conditions, such as sarcoidosis and some lymphomas, can produce excessive amounts of vitamin D, and in these instances, one should move forward cautiously under the supervision of a healthcare professional.


(1) (PDF) http://www.grassrootshealth.net/media/downlo...

(2) http://www.ncbi.nlm.nih.gov/pubmed/19302999

(3) http://www.satsig.net/maps/lat-long-finder.h...

(4) http://www.ncbi.nlm.nih.gov/pubmed/2997282

(5) http://www.ncbi.nlm.nih.gov/pubmed/17426097

(6) http://www.ncbi.nlm.nih.gov/pubmed/16602611

(7) http://www.vitamindcouncil.org

(8) http://www.vitamindcouncil.org/newsletter/20...

(9) http://www.ajcn.org/cgi/content/full/84/4/69...

About the author

David Rostollan holds a Bachelor of Science in Natural Health and a doctorate in Naturopathy. He currently works as a professional health and nutrition consultant. His primary interests include heart disease prevention, chronic illness support, and diet and lifestyle coaching. He can be reached through www.reforminghealth.com

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