As we head into cooler weather, it’s the ideal time to get your vitamin D tested – whether you live in the north like I do or a warmer climate too.
You may not realize that even people who get adequate sunlight may become vitamin D deficient — with an impact on their bones. That’s because vitamin D absorption and utilization differ, sometimes dramatically, from person to person.
Vitamin D needs vary greatly
Here are just a few interesting examples I’ve seen:
- One woman in Connecticut had a vitamin D of level of 33 ng/mL in March — barely above the acceptable lower limit — despite taking 6600 IU of vitamin D during winter. She increased her intake to 8600 IU for several months to reach the ideal 50 ng/mL level.
- Another northeastern woman tested in August — when you’d expect her levels to be highest — was only 35 ng/mL despite taking 2000 IU of vitamin D daily year-round. She needed to add 2000 IU more to reach an optimal level. Contrast this to another client living in Denver, who had 53 ng/mL vitamin D in January when she was only taking 1000 IU daily.
- And then there’s my own case — living in central New York, I was using 2800 units of vitamin D during the summer and getting lots of sunshine from my outdoor activities, but I still tested at 35 ng/mL in October. If I had not raised my wintertime vitamin D intake substantially to 5,800 IU/day, I would’ve had a very inadequate level of vitamin D during the winter.
On average, vitamin D levels are expected to increase 10 ng/mL for every additional 1000 IU of vitamin D — but as you can see, the average doesn’t mean much in real-world situations! That’s why it’s crucial to get vitamin D testing to identify where you are starting — and retest a few weeks later to see if the amount you use is having an impact.
Boroń, D., Kamiński, A., Kotrych, D. et al. Polymorphisms of vitamin D3 receptor and its relation to mineral bone density in perimenopausal women. Osteoporos Int (2015) 26: 1045. doi:10.1007/s00198-014-2947-3
Hollis, B. W., Wagner, C. L., Howard, C. R., Ebeling, M., Shary, J. R., Smith, P. G., … & Hulsey, T. C. (2015). Maternal versus infant vitamin D supplementation during lactation: a randomized controlled trial. Pediatrics,136(4), 625-634.
Drincic, Andjela T., et al. “Volumetric dilution, rather than sequestration best explains the low vitamin D status of obesity.” Obesity 20.7 (2012): 1444-1448.
Mayo Clinic. Vitamin D toxicity rare in people who take supplements, researchers report. ScienceDaily, 30 April 2015.
* Information presented here is not intended to cure, diagnose, prevent or treat any health concerns or condition, nor is it to serve as a substitute professional medical care.