by Joan Vernikos PhD
December 2015
Early this year I shared on the emerging understanding of the importance of Vitamin D for health, and how you can test and manage your own Vitamin D levels.
My own story around Vitamin D has been fascinating and quite
illuminating.
After a summer of sun, swimming and gardening last year my
Vitamin D3 serum level was 25ng/ml 25-OHD. That’s average for the US today, so
my result was a surprise to me. However Vitamin D3 levels dip as we age plus I
have darker skin, which is also a negative factor in Vitamin D synthesis. The
recommended normal range is 30-70 so I knew that something needed to change!
To make matters more interesting I was then and we are now
entering the Vitamin D winter. This means that anyone living north of a
latitude of 35°- almost all in North America and Canada – will get zero benefit
from the sun from November to March. You can view this sunshine calendar to see
how this works across the globe.
Most people in North America are deficient in Vitamin D3
even prior to winter. They either don’t expose enough skin for adequate periods
of time to make enough and/or do not make up for it from food or
supplements. Some like me may have
been taking a daily dose of supplement without really knowing if I need it or
if it was enough. Clearly the solution was to measure, and as I noted above my
levels as of last Fall were low. I joined the Grassroots Health program (www.GrassrootsHealth.org ) to get my
blood levels tested every six months while contributing my data points to their
Global Vitamin D Data base.
My blood tests surprised me and I am sharing here what I
have learned thus far. As I noted above, in September of 2014 at the end of an
active summer and supplementing with a standard dose of 2,000 IU’s of Vit D3 which
I had taken as ‘insurance’, my blood level was 26ng/ml or well below the
recommended normal range of 30-70ng/ml. Grassroots Health’s data suggest that
for every added 1,000 IUs taken the blood level goes up by 5ng/ml. With winter
approaching last year I decided to increase my dose by another 2,000 IUs,
making my daily dose 4,000 IU. By the end of March 2015 six months later by
blood level had increased to 45ng/ml. Out of curiosity I increased my dose by
another 2,000 IUs to 6,000/day. My latest Vit D3 blood level in early October
and after an active, sunny summer was 73ng/ml. So taking the additional
supplements seems to have worked in my case.
Because winter is here I shall maintain this dose of 6,000
IU. Depending on my blood level at
the end of March, I might reduce my intake through the summer by 1,000 or 2,000
IUs and return to 6,000 for the next winter. In my case 1,000 IUs raised my
blood level by more than 5ng/ml. Each one of us is slightly different. One dose
does not necessarily fit all and depending on your state of health you may need
more or less. And it’s important to note that you would need to take extremely
high doses for it to be harmful.
My intention is to share my results in the future while we collectively
learn more about Vitamin D and its impact on health. Please share your own
story with Vitamin D in the comments below.
Here’s to a healthy winter.