Part 2: I got my end of summer vitamin D test results in!
To recap in case you’re just tuning in. This past June I was feeling off so I decided to run some blood tests and found my vitamin D levels were in the subclinical deficiency range sitting at only 34.5 ng/mL!
I could’ve started supplementing right away but instead I decided to do an experiment on myself. I was curious to see how much my vitamin D levels would increase over the summer from just natural sun exposure. I work indoors four days a week but I spend most of my time outside on the weekends. I think this is pretty typical for most people so I thought this would be an accurate representation of how much vitamin D levels actually increase during the summer months.
I tested my vitamin D levels the last day of August and my levels increased from 34.5 ng/mL to 36.8 ng/mL... I was definitely expecting my levels to increase more than only 2 ng/mL over the summer considering a more ideal vitamin D level is around 125 ng/mL!
So is this enough to get me through the winter without supplementation?
The minimum vitamin D value that is recommended is 40 ng/mL. Ideally, we would want to have a value much higher than this so that by the end of the winter we are still sitting above 40 ng/mL.
So is it even possible to get enough vitamin D in the summer to last through the winter?
A study looked at outdoors workers that worked outside an average of 38 hours per week for 16 weeks. They found that to achieve a late winter vitamin D level of 30 ng/mL, a late summer vitamin D level of 50.8 ng/mL was needed (indicating a drop in about 20 ng/mL over the winter months). For most individuals that do not work outside, it would be very difficult to achieve the levels required to sustain adequate levels throughout the winter.
There are some food sources of vitamin D (egg yolks, fatty fish, fish-liver oils, mushrooms), however, for most individuals supplementation is required to maintain adequate vitamin D stores to support immune health, cardiovascular health, blood sugar regulation, skin health and mental health.
I know for myself, the hardest part about supplementing vitamin D is remembering to take my vitamin D supplement everyday…
This winter I’m going to try a different approach. Stay tuned for my next post on my plans to get my vitamin D levels up fast and easy.
References:
Barger-Lux, M. J., & Heaney, R. P. (2002). Effects of above average summer sun exposure on serum 25-hydroxyvitamin D and calcium absorption. The Journal of Clinical Endocrinology & Metabolism, 87(11), 4952-4956.
Hanley, D. A., & Davison, K. S. (2005). Vitamin D insufficiency in North America. The Journal of nutrition, 135(2), 332-337.
