After I reached the 8 week mark of my Carb Back-Loading experiment, I planned to draw a series of blood tests to see where things stood compared to my most recent set of labs which were drawn after doing Carb Nite for 10 weeks.
As a quick review, here are some of the basics of Vitamin D that I addressed in my prior post:
Basics of Vitamin D
- It is a hormone derived from cholesterol
- It can be made in the skin with exposure to sunlight
- It can also be ingested with food or supplementation
Effects of Vitamin D
- Maintains calcium levels in body which is important for bone health
- Regulates gene expression
- Helps immune function
- May provide anti-cancer effects
- Vitamin D levels need to be in the 50 -70 ng/mL range for thyroid hormone receptors to respond properly
- Low Vitamin D levels are seen in obesity, although I’m not entirely sure if it’s known whether obesity causes low vitamin D levels, or if it’s the other way around.
Optimal Range of Vitamin D Levels
- Most sources I’ve come across recommend 50 – 70 ng/mL
Chris Kresser’s Thoughts:
- Chris Kresser actually recommends a level of 35 ng/mL with the range between 25 – 50 ng/mL in the supplemental material provided with his Paleo Code book.
- He states that there isn’t much evidence indicating levels above 50 ng/mL to be beneficial with some evidence that it can cause harm. Higher levels have been linked to:
- Decreased bone density
- Heart attack
- Kidney stones
My Vitamin D Levels
December 16, 2013 – 31.3 ng/mL (Normal range provided by the lab 30.0 – 100.0 ng/mL)
My plan after seeing such a low level (this was before I had read Chris Kresser’s Paleo Code online supplemental info) was to try to get as much sunlight as possible and to start an aggressive regimen of oral supplementation.
April 4, 2014 – 54.3 ng/mL (Normal range provided by the lab 30.0 – 100.0 ng/mL)
While I did manage to get outside a bit, given the length of this winter and severity of the polar vortex, it wasn’t for more than a couple days when I was able to escape to the west coast. I don’t think this played a significant role in increasing my levels.
I think the oral supplementation was responsible for the majority of the change. I used Mark Sisson’s:
- Primal Blueprint Vitamin D – 2000 IU per capsule
I tried to average anywhere from 6000 to 8000 IU per day. Some days I would take up to 12000 IU and other days I would skip. I didn’t bring the pills with me when I went to Antarctica or when I went to Italy so there were definitely a few weeks when I took a supplement holiday (needless to say, I didn’t to much tanning in those places).
In any case, my haphazard supplementation seemed to do the trick in raising my levels to my intended goal of between 50 – 70 ng/mL.
However in light of Chris Kresser’s thoughts, I’ll probably cut back on my supplementation with a goal of around 2000 – 4000 IU per day with less on days I’m able to get outside.
I also probably don’t need to get this checked again at least for another 6 – 12 months. Trying to target a range of 40 – 60 ng/mL seems to be a reasonable way to split the difference!