After four sunlight-deprived years of college in Syracuse, New York (a region notorious for its overcast weather), I decided to move to Honolulu, Hawaii in 2018. I spent three years getting plenty of sunshine while I was running or practicing yoga outside, swimming in the ocean, and socializing on the beach.
Six months after I moved back to New Hampshire (my home state), I had my vitamin D levels tested. My 25(OH)D serum levels were 50 ng/ml, which is just entering the truly optimal range (i.e., at or above 50 ng/ml). Although I hadn’t been regularly supplementing with vitamin D for a few years, I managed to sustain healthy D status thanks to my (safe) sun exposure and a relatively fish-heavy diet.
I thought I could put off supplementation just a little bit longer, but last month I had my levels tested again and discovered that 25(OH)D results had dropped to 30 ng/ml in just 16 months! While my test results were listed in a little green box and stated they were “normal,” I know that 30 ng/ml—while the cutoff for clinical sufficiency—is not an ideal serum level.
In fact, without upping my vitamin D intake, the likelihood of slipping into vitamin D insufficiency is practically guaranteed. I’m certainly not in the minority, either: Approximately 41% of U.S. adults are clinically insufficient1 in vitamin D while another 29% are straight up deficient.
