November 5, 2014

Letter from the Director


At GrassrootsHealth headquarters in San Diego, we are busy planning for our upcoming seminar, Vitamin D for Public Health - Integrating Sunshine, Supplements and Measurement for Optimal Health. We have some fantastic speakers lined up, a great venue, and a spectacular hotel walking distance to the event. If you are thinking of attending, I encourage you to register now, as space is limited to 165 attendees. 


In this issue of our newsletter we revisit the D*action cohort for more of Your Data, Your Answers. We analyze the data many different ways and this month we wanted to show you how your vitamin D replete community looks with respect to age. How do the different age groups supplement? Are there differences in serum level by age? 


I always find it interesting to look at the data, and this time is no different. Sometimes it supports your ideas and other times it surprises you. Let us know what you think about this set. 


Hope to see you in San Diego,


Carole Baggerly 

Director, GrassrootsHealth

A Public Health Promotion & Research Organization

Moving Research into Practice NOW!

Your Data Your Answers


outdoor-lg-family2.jpg How Old is Everyone?


D*action is a study cohort with over 7,800 members who have completed at least one questionnaire and blood test. The median age of D*action participants is 54 years old. For this analysis we have divided the group into the following age ranges:

15-34 - sample size is 763, 11%

35-49 - sample size is 1882, 27%
50-64 - sample size is 2917, 42%
65 or greater - sample size is 1405, 20%

Intake by Age


In the chart below, you can see that as age increases, so does the percentage of those taking supplements. You can also see that the median vitamin D intake also increases with age. 



Serum Level by Age

This next chart shows that the median serum level of vitamin D (25(OH)D) increases with age. If you look at the blue bars representing the youngest age group (ages 15 - 34), you can see that more of that group is in the lower serum level ranges, <20 or 20-39 ng/ml than any other age group. You can also see that those in the oldest age group (ages 65+), represented by the purple bars, are more likely to be in the higher serum level ranges of 40-60 or >60 ng/ml than any other age group. 


We found no difference in the dose response relationship by age; as supplement intake increases, serum level increases, regardless of age. Rather than thinking that you need to take more supplements as you age, perhaps we should instead think that you should start with supplements at a younger age and continue so that you can have a long, healthy lifetime with your 25(OH)D level in the recommended range of 40-60 ng/ml.



Conclusion - Supplements are Important at Any Age


Regardless of age, those participants in our D*action group who reached the recommended level of 40-60 ng/ml took an average of 4000 IU daily. You can use this dosage as a baseline, but remember to test your blood regularly to make sure you are in the recommended range because individual requirements do vary.

Editor's Note


This data was interesting to me in two ways. First, I am surprised to learn that so many of our participants are above 50 years old. Why aren't younger people more concerned about their health and their vitamin D levels? I would love to see this cohort change over the next 5 years and be more balanced in age - as we see more people get concerned with their health and understand the value of vitamin D for disease prevention.

The second thing that amazed me was that dose response was the same over age. I have typically thought that someone over 50 would need more supplements to achieve a serum level than someone who is 30. So - I was wrong! That also means that as we help our children (those under 18) reach the right serum level we should keep this in mind and make sure we supplement (and test) accordingly.



Susan Siljander      

Marketing Director, GrassrootsHealth

A Public Health Promotion & 

Research Organization  

Moving Research into Practice NOW!



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Vitamin D FAQs for Pregnancy, Breastfeeding and Babies
Serum Level vs Intake Charts
Vitamin D and Aging
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