Too Much, Not Enough Vitamin D Poses Health Threat

FORT LAUDERDALE, Fla.Americans with higher vitamin D blood levels have substantially lower risks of degenerative disease, but levels that are too high can harm the heart, according to a study presented by the Intermountain Medical Center (IMC), Murray, UT, at the 84th annual scientific meeting of the American Heart Association (AHA), Nov. 12 to 16 in Orlando, FL.

The study, which measured 25-hydroxyvitamin D blood levels in 132,000 Americans, found those whose vitamin D levels were in the 61 ng/ml to 80 ng/mL range had a 52-percent reduced risk of diabetes compared to those with deficient levels below 20 ng/mL. Those whose 25-hydroxyvitamin D levels ranged from 81 ng/ml to 100 ng/mL had a 36-percent reduction in hypertension rates when measured against the deficient group. Compared to people in the deficient range, those with higher blood levels of 25-hydroxyvitamin D had significantly lower risk of heart failure, depression, coronary artery disease (CAD), kidney failure and prior stroke.  

However, results showed vitamin D levels can get too high. Those whose 25-hydroxyvitamin D level exceeded 100 ng/mL had an atrial fibrillation incidence greater than those whose levels were below 100 ng/mL. Atrial fibrillation refers to irregular rhythm in the upper chambers of the heart.

 Since most of our members are aware of the importance of optimal vitamin D levels, frank deficiency levels less than 20 ng/ml are unusual, though we still see the need for consistent dosing to ensure optimal vitamin D status," said William Faloon, founder, Life Extension®, which markets dietary supplements.

The January 2010 issue of Life Extension Magazine® identified an optimal range of 25-hydroxyvitamin D for health between 50 to 80 ng/mL. Out of this large group of IMC study participants, a small number (291 or 0.22 percent) had 25-hydroxyvitamin D levels over 100 ng/mL," Faloon said.  This high level exceeds what Life Extension, as well as other scientific experts in vitamin D metabolism, have long recommended."

Study authors recommended people have their blood tested to ensure they are taking the proper dose of vitamin D.