MAC wrote:I spend a LOT of time in the sun, so my thinking is I am not likely lacking.
Good you're getting tested anyway. Rhonda Patrick, in her 'How to Personalize Your Nutrition Based on Your Genes' .pdf includes CYP2R1 variants affecting vitamin D levels:
Vitamin D and C YP2R1
There are two common polymorphism in a the C YP2R1 gene (vitamin D 25hydroxylase) that that converts vitamin D3 into 25hydroxyvitamin D, the major circulating form of vitamin D that gets converted into the active steroid hormone. This polymorphism can lower the conversion of D3 into 25hydroxyvitamin D and, thus, is associated with lower circulating levels of 25OHD and this has been associated with reduced longevity and higher allcause mortality. It is known that supplementing with 1,000 IU of vitamin D3 per day generally raises serum 25hydroxy levels by 5ng/ml. This may not be the case for people with these polymorphisms. and may require higher vitamin D supplementation doses to achieve the same serum levels as individuals with out these polymorphisms. R eference 1, R eference 2, Reference 3
The following polymorphisms are associated with reduced CYP2R1 activity and low 25hydroxyvitamin levels:
● rs10741657 (G;G)
● rs12794714 (A;A)
● rs2060793 (A;A)