The reference range is provided simply to give an idea of how these values compare to a large number of others taken from a relatively healthy population. The reference range of 20-80 ng/mL refers to the range of blood vitamin D levels from a normal population. When we at OmegaQuant have more of our own vitamin D data, we will create our own reference range encompassing the values from 99% of individuals that we test. Currently, we are utilizing the reference range from another dried blood spot testing lab.
The desirable range of 30-50 ng/mL is a “goldilocks” range where we believe most of the health benefit has been realized (as compared to having low levels) and there doesn’t seem to be much extra benefit in having higher levels. Many research studies show that >30 ng/mL is predictive of a lot of good health outcomes (see list below), so we consider it a therapeutic threshold.
- Lower risk of overall mortality: People with a blood level of 30 ng/mL and above had a lower risk of mortality (Garland et al. 2014).
- Lower risk of cardiovascular disease (CVD) and cancer mortality: Lowest risk for death from all-causes, cancer and CVD in individuals with a vitamin D blood level of at least 30 ng/mL (Michaelsson et al. 2010).
- Lower risk for respiratory tract infections: Those with vitamin D blood levels at or above 30 ng/mL had the lowest risk of upper respiratory tract infections (Ginde et al. 2009).
- Lower risk of hip fractures and falls: Older individuals who achieved a vitamin D blood level of at least 30 ng/mL had a reduced risk of hip fractures (Bischoff-Ferrari et al 2009).
- Lower risk of preterm birth: Pregnant women with levels of at least 30 ng/mL were at the lowest risk of preterm birth, as well as babies born with low birth weight and small for gestational age (Miliku et al. 2016).
The other important thing to consider is what it takes to have very high vitamin D blood levels. For example, a vitamin D blood level of 70 ng/mL may impart more health benefits than a level of 30 ng/mL, but the supplemental dosage required to reach those levels could be very high. On average, for someone with low levels to reach 30 ng/mL, one needs at least 1000-2000 IU/day, and the upper limit is currently set at 4000 IU/day.
These are our recommendations, but we always advise you to consult with your doctor before making any dietary changes, especially if it includes taking high doses of a vitamin D supplement. Many other organizations have their own targets and rationales (Institute of Medicine, Endocrine Society), and you are free to use our Vitamin D test to track your progress towards their recommended target ranges if you wish.