A new meta-analysis might just shed a tiny bit more light on the ongoing debate about what constitutes an efficacious and safe dose of vitamin D—or more specifically, what blood level we should be aiming at in order to max out health benefits, but avoid any potential negative effects.
Researchers at the Brigham and Women’s Hospital in Boston said the data confirmed a link between low circulating vitamin D levels and greater risk for cardiovascular events. However, the benefits seemed to flatten out after reaching blood levels of 20 ng/ml, all the way of to levels of 60 ng/ml. The results are expected to inform future trials in terms of optimal dose, researchers said.
At least they didn’t find that too-high vitamin D blood levels could actually harm heart health, as some recent studies have done. A Johns Hopkins meta-analysis published in the American Journal of Cardiology in January found that among the more than 15,000 study subjects ages 18 to 85, when blood levels topped 21 ng/ml, they were no longer associated with a decrease in the inflammatory marker C-reactive protein, but instead were linked with a slight, progressive increase as blood levels rose.
Functional Ingredients Editor-in-Chief Todd Runestad recently blogged on this topic for a vastly different take on another recent study linking high D blood levels with “heart problems.”
To add another wrinkle, a study linked high CRP in some elderly with “normal cognition.” According to the author, there seems to be something unique about the chemistry of people who survive to a very old age, so that high CRP has the opposite effect of what you see in younger individuals.
And so the meandering path of medical research continues. Do you think there are health risks of taking too much vitamin D? Please share in comments below.