July 29, 2015

Director's Letter 


GrassrootsHealth has two big treasures:  YOU and our Scientists' Panel. We'd like to help make a more direct connection with the questions you'd especially like to have answered by the scientists.  As we feature a specific scientist and his or her work, we're adding the capability for you to submit your personal questions on that topic.  We will then provide their answers to key questions in a subsequent newsletter. 

Please ask your questions within 48 hours of receiving the newsletter so that the scientist has time to answer.  This week, our key topic is Why Daily Dosing is Important with our focus on Drs Hollis and Wagner's publication.  If you have a question about this topic (daily dosing), just click here and type it in. We'll answer your questions in a future newsletter.


As you read further into this newsletter, you will learn some of the groundbreaking information that came from a couple of our panel scientists last year. Drs Bruce Hollis and Carol Wager published a paper on why dose intervals are important for vitamin D function.   


On a very practical note, if daily dosing is important for some of our tissues to help demonstrably prevent or control influenza, respiratory infections, gingivitis, MS, as a few examples, how can you not adopt a daily schedule for intake and/or UV exposure???


I hope after reading this newsletter that you understand the importance of daily dosing. Please do take the time to listen to Dr. Hollis' webinar on dosing intervals, as it will cement in your mind the importance of daily dosing. And, 'Ask a Scientist'




Carole Baggerly 

Director, GrassrootsHealth

A Public Health Promotion & Research Organization

Moving Research into Practice NOW!

Daily Dosing 

How is vitamin D absorbed and used in your body?
Vitamin D3 enters the body through sun exposure, diet or a supplement and goes into the blood stream where much of it binds to the vitamin D binding protein (VDBP) -- a protein that carries vitamin D compounds into circulation. From there, vitamin D3 functions within two systems in the human body - the endocrine system and the autocrine/paracrine system.
#1 - The Endrocrine System - for skeletal health

The endocrine system - this long studied system for action by vitamin D - is where calcium homeostasis and bone health are maintained. Vitamin D3, from UV exposure or diet, is delivered to the liver, converted to 25-hydroxyvitamin D, or 25(OH)D, and moved into circulation where it has a half life of approximately three weeks. As necessary, 25(OH)D is then transferred to the kidney where it is further converted to the active form of 1,25(OH)2D which has a half life of only a few hours. This active form can then help control calcium absorption and bone health. All the successful studies on vitamin D and bone health have benefited from the long half life and availability of 25(OH)D. For bone health, the important thing is the amount of 25(OH)D available, rather than direct intake of vitamin D.

#2 - The Autocrine/Paracrine System - for autoimmune health

What has not been appreciated until relatively recently is that in addition to being delivered to the liver for conversion to 25(OH)D, vitamin D is also delivered directly to all tissues of the body. Many of these tissues, such as breast, colon, prostate, and brain, can convert vitamin D to its active form within the tissue. It is through this process that vitamin D can help enable the cells to fight against infections, disease, and autoimmune disorders. Vitamin D has a half life in the autocrine system of roughly 24 hours, so in order for it to have a meaningful impact on cellular functions, you need a new supply of it every day. This new understanding means that frequency of dosing matters when testing for disease reduction and immune control - large monthly or quarterly doses that are effective for bone health will not show positive results for disease reduction. For disease prevention and treatment, daily dosing (food, sun, supplement) is very important!
Do nursing mothers need daily D3?
Without daily dosing, breast feeding mothers could have 50-60 ng/ml of measurable 25(OH)D in their blood but no measurable vitamin D3 in their breast milk. After vitamin D3 has been turned to 25(OH)D it cannot enter the breast milk. The only way to get vitamin D in breast milk is by dosing daily - either by sun, diet or supplementation. Dr. Hollis' research indicated that 6,400 IU/day was necessary for breast feeding mothers to attain sufficient vitamin D (to the value of 400 IU/day for the infant) in their breast milk.
Why does this matter for clinical trials?
Most of the clinical trials conducted in the past 40 years have focused on the endocrine system and have consistently shown the positive effects of vitamin D on bone health regardless of dosing regimen (from daily to quarterly). In the past 10 years, many new clinical trials have focused on non-skeletal outcomes such as autoimmune disorders, cancer, cardiovascular disease and infections. These new studies have also used various dosing regimens--but have yielded inconsistent results. Those with adequate daily vitamin D inputs have largely shown positive results while those with longer dosing intervals have shown no vitamin D effect. While 25(OH)D levels are maintained in these studies, it is the vitamin D3 levels that are essential to these systems. Therefore, it is necessary to design a clinical trial based on the physiology of the system of interest in order to accurately assess the effect of vitamin D in the body.
"Circulating vitamin D, the parent compound for tissue vitamin D activation, likely has an important direct physiological role beyond what was originally anticipated through the local tissue autocrine system." Schedules for vitamin D dosing could have profound effect on health outcomes.

Video of the Week 


Vitamin D - Dosing Interval
Webinar with Bruce Hollis, PhD
Professor of Pediatrics, College of Medicine
Medical University of South Carolina
August 2014 


Watch Video 


Dr. Bruce Hollis Dr. Bruce Hollis received his Bachelors of Science and Masters of Science from the Ohio State University. His PhD was obtained in experimental nutrition from the University of Guelph in 1979. He did an endocrine fellowship at Case Western Reserve University from 1979-1982 and was then appointed to Assistant Professor. In 1986 he moved to The Medical University of South Carolina as Associate Professor of Pediatrics. Today, Dr. Hollis is the Professor of Pediatrics, Biochemistry and Molecular Biology at The Medical University of South Carolina as well as the Director of Pediatric Nutritional Sciences. He has been involved in vitamin D research for the past 35 years and has published in excess of 200 peer reviewed articles. He has had many National Institute of Health grants and currently has 2 active research project grants under the National Institute of Health.


This webinar consists of a 24 minute presentation by Dr. Hollis, followed by 15 minutes of questions and answers. Hollis thoroughly explains how vitamin D supplementation is processed by both the endrocrine and autocrine systems. He reviews clinical trials that have had success or failure and correlates their results with their dosing strategy. It is a very technical presentation, but if you don't yet agree that daily dosing is important, then please watch this webinar so that you can fully understand the importance of daily dosing.

Watch Video  

Editor's Letter 


One of the things I appreciate about the scientists from our panel is their dedication and passion for vitamin D and preventive medicine. Dr. Hollis is no different. Not only during this talk, but also on other occasions when I have heard him speak, he can't help but educate others about the importance of daily dosing. His studies of pregnancy and breast milk helped him unearth this information - but it applies to all disease prevention. This new piece of information about vitamin D is not well known.  

Bolus (bulk) dosing has been prevalent in studies largely because it is easier to ensure compliance. It is easier to have subjects come to the lab weekly, or monthly, or quarterly for a large dose than to see them every day, or leave them to take their supplements on their own. While this has produced successful results for studies on bone health, it has not been successful for other health conditions. Now we know why.     


This is a paradigm shift for many, so please send this around your social networks so that people understand. In his talks, Dr. Hollis talks about supplementation - but daily dosing truly applies to daily vitamin D - whether from sun exposure, supplementation, or from the foods we eat every day.  


Spread the word!


Susan Siljander       

Marketing Director, GrassrootsHealth

A Public Health Promotion & 

Research Organization  

Moving Research into Practice NOW!
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Vitamin D in the News

Go ahead, soak up some sun

Michael F. Holick, PhD  

Boston University Medical Center

Washington Post

July 26, 2015

Read Article

Dr. Bruce Hollis

If you have a question about this week's news - please click here and ask away. We will publish the answers in a future newsletter. 

What is the state of women of child-bearing age in the US?

Fewer than 10% of US women of childbearing age (18-45 years) have vitamin D levels at or above the currently recommended minimum for pregnancy, 40 ng/ml. Supplementation is a safe and easy way to correct deficiency, and regular testing can be used to monitor progress.


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The Role of the Parent Compound Vitamin D with Respect to Metabolism and Function: Why Clinical Dose Intervals Can Affect Clinical Outcomes

Bruce Hollis, PhD

Medical University of South Carolina

Read Paper


Vitamin D requirements during lactation: high-dose maternal supplementation as therapy to prevent hypovitaminosis D for both the mother and the nursing infant

Bruce W. Hollis, PhD 

Carol L. Wagner, MD 

Medical University of South Carolina

December 2004

The American Journal of Clinical Nutrition

Read Paper 

Video of the Week

Vitamin D - Dosing Interval

Bruce Hollis, PhD

Medical University of South Carolina


Watch Video 

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