August 26, 2015

Director's Letter
Carole Baggerly
Director, GrassrootsHealth

KEY Questions: How much should I take? Is it toxic?

Since the start of GrassrootsHealth, these have been the most common questions.  At the beginning, in 2007, we (my husband and research partner, Leo, and I) traveled the US and Canada to meet with the most experienced vitamin D researchers to get answers to those questions.  The guiding answer then and still NOW, is to focus on maintaining a serum level range of 40-60 ng/ml (100-150 nmol/L). There is no definitive answer to the 'how much should I take' without testing one's serum level.

Our very first research paper which many of you contributed to (referenced below) added much light to the question of toxicity.  It's hard to get to without taking >30,000 IU/day and, the instances of toxicity continue to be accidents, either of understanding or industrial mistakes. 

Using the charts that have been published by GrassrootsHealth is still the best way for an individual to get a start on what they should take to achieve their desired serum levels.

On a personal note, I take 10,000 IU/day (at breakfast) to achieve about 60 ng/ml.  My husband takes 5000 IU/day to achieve the same level.  Why the difference?  Yet to be determined.  Please test your serum levels at least once/year (in late March if only once, when it will be lowest) and adjust your intake from there. 

Our major health problem is still the DEFICIENCY of vitamin D. 

Keep spreading the word.

Carole Baggerly 
Director, GrassrootsHealth
A Public Health Promotion & Research Organization
Moving Research into Practice NOW!
Feature Story
Can Vitamin D be toxic?   

Why do doctors tell you your level is too high?

If your doctor is not an active advocate for vitamin D, they are probably getting their vitamin D guidelines from one of the following two sources.

The US Institute of Medicine (IOM) Recommended Dietary Allowance (RDA) of vitamin D is 400 IU per day for children younger than 1 year of age, 600 IU per day for children at least 1 year of age and adults up to 70 years, and 800 IU per day for older adults. The IOM concludes that these dosages will cover the requirements of 97.5% of the population to reach what they consider to be an adequate level of serum 25-hydroxyvitamin D [25(OH)D], 20 ng/ml.

The US Endocrine Society's Clinical Practice Guideline suggests that 400-1000 IU per day may be needed for children younger than 1 year, 600-1000 IU per day for children aged 1 year or more, and 1500-2000 IU per day for adults aged 19 years or more to maintain 25(OH)D above 30 ng/ml. Patients with malabsorption conditions, obese patients, and patients taking certain medications may need two to three times more vitamin D to sustain their vitamin D status.

When shooting for these targets, your doctor may tell you that a vitamin D level of 30 ng/ml is high enough or that 40 or 50 ng/ml is too high. We disagree.

GrassrootsHealth, along with some of our scientists, published a paper showing that the IOM miscalculated. This paper uses D*action data to show that if you really want 97.5% of the population to be 20 ng/ml, then the RDA should be 7,000 IU/day from all sources.

GrassrootsHealth recommendations

When GrassrootsHealth held our first seminar, Diagnosis and Treatment of Vitamin D Deficiency, in April 2008, we started with the support of 14 pioneers in vitamin D research. Today, 48 international scientists have signed a Vitamin D Scientists' Call to Action agreeing that: 
1. There is a vitamin D deficiency epidemic (40%-75% of the world's population is vitamin D deficient).
2. 20-50% or more of many common diseases could be prevented with vitamin D sufficiency.
3. 40-60 ng/ml is the recommended serum level of vitamin D  - both safe and effective for disease prevention.

Disease Incidence Prevention Chart
GrassrootsHealth has developed a Disease Incidence Prevention chart that clearly shows the vitamin D serum levels associated with the reduction/prevention of several diseases. As you can see on the chart, if your vitamin D blood level is between 40-60 ng/ml, you are in the sweet spot for disease prevention.
What if your level is above 60 ng/ml?

The IOM and NIH say that levels over 50 ng/ml are unsafe

The Endocrine Society considers any level below 100 ng/ml as safe, and > 150 ng/ml as a level of concern.

GrassrootsHealth is aligned with the Endocrine Society in this case and is not concerned about any blood levels lower than 100 ng/ml.

Vitamin D toxicity

Vitamin D toxicity, also known as hypervitaminosis D, is a rare but potentially serious condition that occurs when you take in too much vitamin D. Excess amounts of vitamin D can cause abnormally high levels of calcium in the blood, which can affect bones, tissues, and other organs. Left untreated, this condition can lead to high blood pressure, bone loss, and kidney damage. Symptoms of vitamin D toxicity include: lack of appetite, excessive thirst, nausea, abdominal pain and increased urination.

With one exception at 194 ng/ml while taking 50,000 IU/day, GrassrootsHealth is not aware of any documented cases of vitamin D toxicity for anyone under 200 ng/ml. For more on toxicity, we suggest that you read Dr. John Cannell's blog, Latest studies on Vitamin D toxicity. It is an interesting look at toxicity - three cases of diagnosis (including the one exception mentioned), and there were no long term effects once supplementation was discontinued.

GrassrootsHealth has data showing toxicity is virtually impossible with standard doses

Getting a potentially toxic vitamin D level (above 200 ng/ml) is typically hard. Of our D*action participants, the average serum level is 43 ng/ml, 43% of our cohort are below 40 ng/ml, and 21% are above 60 ng/ml.  Our dose response curve (below) shows the rise in 25(OH)D with increasing dosage (the blue line) is more gradual in the upper end of the range, demonstrating that as you get into the higher ranges, more and more vitamin D is needed to raise your vitamin D level.

Click to Expand

One of our first papers, Vitamin D Supplement Doses and Serum 25-Hydroxyvitamin D in the Range Associated with Cancer Prevention, studied the serum 25(OH)D concentration and self-reported vitamin D intake from D*action participants (3,667 individuals). The dose response curve above was one of the outcomes of this study. The other conclusions were:


  • The supplemental dose ensuring that 97.5% of this population achieved a serum 25(OH)D of at least 40 ng/ml was 9,600 IU/day.
  • Universal intake of up to 40,000 IU/day is unlikely to result in vitamin D toxicity.


A new paper, published in May 2015 from the Mayo Clinic, confirms our findings. Changing Incidence of Serum 25-Hydroxyvitamin D Values Above 50 ng/mL: A 10-Year Population-Based Study by Dudenkov et al. studied a population in Minnesota from 2002 to 2011. As vitamin D deficiency became more prevalent in the news, more people supplemented and this study found a significant rise in vitamin D levels (specifically looking at values above 50 ng/ml, the IOM's unsafe level). But... they did NOT find any increase in clinical cases of vitamin D toxicity. So, while the vitamin D levels rose, there was no rise in toxicity.

What should you do?

One thing is clear from our data and from many of the scientific papers - response to vitamin D supplementation varies greatly person-to-person due to many factors (weight, skin color, latitude, age, diet, current disease). The best thing to do is to test twice a year and stay updated on the information from the research community.  At this time, the GrassrootsHealth panel still sees the 40-60 ng/ml as the physiological level (found in the out-of-doors population) as well as that demonstrated by the current science.


Personal Profile
My Vitamin D Story
by Horst Goering 

Horst Goering, 80+ years
Retired Professor at the Humboldt-University Berlin, Germany
Married 58 years to Svetlana Koshuchowa
2 children, and 3 grandchildren - living in the US and Germany

The beginning, by Horst Goering

During all the years at the university my health was not very good. For this and other reasons I left the university life and applied myself in different fields, years after retirement. My health was sometimes better, sometimes worse. A few years ago (2013), my situation could be described as following:
  • Chronic pain in the neck, shoulders, back and right leg. Diagnosis: a slipped disk. Surgery was recommended. I declined.
  • Two or three times a year I had a very heavy flu or cold (4-6 weeks recovery with antibiotics)
  • Tiredness and intensive nightly sweating
  • Neurodermitis
  • Gum inflammation and chronic periodontitis
  • Shingles (Herpes Zoster) two or three times a year
  • General weakness and powerlessness
  • Lack of motivation and signs of depression
  • Irritable bowel syndrome for more than 50 years
Vitamin D therapy - did it work?

Was it time to go? I was already more than eighty years old and, maybe, that was it? My wife's situation was not much better. In the summer of 2013, both my wife and I had no strength, no drive, just weakness ...!  I asked my doctor to check my vitamin D level again. The result: 19.6 ng/ml. At this time my doctor, without hesitation, prescribed Dekristol (20,000 IU vitamin D). I started a vitamin D-therapy according to von Helden. This means, first day - 200,000 IU, then 5 days each time 20,000, later 20,000 IU every third day. After 2-3 weeks I felt already better. (7 weeks later his vitamin D level was 42 ng/ml).

At present, 2 years after the beginning of vitamin D-therapy, we are back to life. I test my vitamin D levels twice a year and they are usually about 70 ng/ml. I take 50,000 IU/week. What happened during that time?
  • After only 4 days, the pain in the neck and shoulders disappeared
  • After about 3 weeks, nightly sweating disappeared
  • After 4 - 6 weeks, gum inflammation and chronic periodontitis was gone
  • After 6 - 8 weeks, all symptoms of neurodermitis vanished
  • I no longer suffer from flu or cold
  • The same is true for shingles (Herpes Zoster)
  • Even my colon is working quite normal now
Life again!

Vitamin D? I think you can say that I am the living example that it is possible to turn just before the cemetery gate back into the stream of communal living thanks to vitamin D. The same is true for my wife, for our immediate neighbors, for some friends, for a lot of other people who came to my lectures or were reading my flyers and pamphlets, in Germany and in Moscow and even some in the US. Each of us is an individual case - a "meaningless nothing" to the statistic-driven modern medicine. But for me it means everything! It makes the difference between death and life. My life!

Vitamin D proponent and researcher

Since 2013 I have spent all my time studying the hormone cholecalciferol, so-called "vitamin D". I started sharing my knowledge with friends and other people, about what I had read and what my own experiences of its effects on me were. Some hundreds of them improved their quality of life to different degrees after vitamin D-therapy. One of my flyers came to an editor of the journal Biochemistry. At the end of October 2014, I was asked to write a review on vitamin D; I did not know what to do. At our age? After all we suffered?! Neither my wife nor I have medical training, we are "just" biologists and long retired. Nevertheless, we agreed and you can read this paper.

What would Horst tell a neighbor about vitamin D?

What about vitamin D? It means cholecalciferol, a hormone, the so-called vitamin D. This is a unique compound in nature. We cannot synthesize it by ourselves. There is some amount in our food, at best, about 10% of what we need. But it is synthesized by UV-B-irradiation in our skin if there is enough sunshine. We need it urgently and permanently from our childhood up until old age. An optimal level of vitamin D protects us against 60 to 80% of all age-related diseases, against pain in neck, shoulder, back etc., against cold and flu. Vitamin D regulates our power of resistance.

Editor's Letter
Susan Siljander
Marketing Director, GrassrootsHealth

I just want to go on record as saying that it is hard for many people, including myself, to get their blood level above 60 ng/ml. I have tried and tried, and it is not happening for me. I equate it with losing those pesky last 5 pounds - it is relatively easy to lose weight in the beginning, but then the last bit takes much more concentration and focus. So, while we talk about these higher levels of vitamin D - know that you are in a disease preventive range between 40 - 60 ng/ml - keep up the good work and keep testing regularly to maintain your level.

I also want to thank Horst for sharing his story. It was very interesting and as always it is good to hear a story with a happy ending - enjoying life and all it has to offer.

Please take advantage of our "Ask a Scientist" feature - and you can read six questions and answers from you, addressed by Dr. Robert Heaney, GrassrootsHealth's Research Director and Dr. Cedric Garland, Professor, University of California at San Diego Preventive Medicine.

Have a great week!

Susan Siljander
Marketing Director, GrassrootsHealth
A Public Health Promotion & 
Research Organization  
Moving Research into Practice NOW!
Order Your Home Vitamin D Test TODAY!
Your participation in this project funds all the GrassrootsHealth research and promotion.

The "vitamin D winter" is coming!

Dr. Adrian Gombart, the Linus Pauling Institute's resident expert on vitamin D, will discuss the importance of vitamin D for healthy bones, reducing cancer, fighting infections, and the immune system.

August 27, 2015 at 10:30am (Pacific Time)

Questions answered by
Cedric Garland, Dr PH FACE
Robert Heaney, MD

Vitamin D and MS

Is there a condition that doesn't allow some people to absorb vitamin D?

Vitamin D and chemotherapy 

Questions Answered by
John J. Cannell, MD

If you have a question about vitamin D toxicity-
We will only answer questions about toxicity, please do not send other questions

We will publish the answers in a future newsletter.  
Open to any US woman, 18 years or older, at 12-17 weeks of pregnancy


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Call to Action
48 scientists agree
Read now

Disease Incidence Prevention Chart
A chart showing the required vitamin D serum levels for prevention of many diseases.
View Now

Vitamin D Supplement Doses and Serum 25-Hydroxyvtitamin D in the Range Associated with Cancer Prevention
Cedric Garland, Dr. PH, FACE
University of California at San Diego
Published in association with GrassrootsHealth
Read Paper

Changing Incidence of Serum 25-Hydroxyvitamin D Values Above 50 ng/mL: A 10-Year Population-Based Study
Daniel V. Dudenkov, MD
Mayo Clinic, MN
May 2015
Read Paper

Risk Assessment for Vitamin D
John N. Hathcock
Andrew Shao
Reinhold Vieth
Robert Heaney
January 2007
Read Paper

Latest studies on Vitamin D toxicity
Dr. John Cannell
General Medical Recommendations
Published by NIH
Based on IOM recommendations
Vitamin D data sheet

Vitamin D - the Sun Hormone. Life in Environmental Mismatch
Horst Göring
Svetlana Koshuchowa
April 2015
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