In fact, in the last episode of mindbodygreen podcastBredesen explains that vitamin D levels are dangerously low [i.e., 25(OH)D serum test results at or below 20 ng/ml—the clinical cutoff for vitamin D deficiency] It is one of the main contributing factors to the cognitive decline that he sees in his patients.
“It is surprisingly common to see people develop cognitive decline and have a vitamin D level of 19 or 20 [ng/ml]’ He shares.
How did these individuals become deficient in vitamin D in the first place? According to Breden, this is a combination of lifestyle habits and food choices: “They live inside, they don’t get out enough, they don’t take in their vitamin D, or they don’t absorb the vitamin D they take in.”
So, we’re left with supplements. But as Bredesen mentioned, some people take vitamin D supplements and see no improvement in their D levels — or their cognitive function.