To better understand normal and deficient vitamin D levels, researchers studied the relationship between a hormone (parathyroid) and vitamin D in African American and white 50-to-79-year-old adults. Parathyroid hormone is produced in the body to help regulate calcium balance, and as vitamin D levels go up, parathyroid hormone levels go down.
The bottom of the normal vitamin D range is considered the level above which parathyroid hormone levels cannot be lowered any further. Current guidelines set this number at 30 ng per ml, meaning a person would not be considered low in vitamin D until his or her blood level dropped below 30 ng per ml.
The study suggests the “normal” vitamin D level may be different for African Americans and whites.
In other words, adequate vitamin D blood levels may begin around 20 ng per ml for African Americans, and around 30 ng per ml for whites.
This study suggests current optimal or “normal” vitamin D levels in whites may not be applicable to African Americans, or black people from any location. This is important: for African Americans, one study even suggests harm with higher vitamin D levels. Among 340 African Americans with type 2 diabetes, those with the highest D levels were more likely to have plaque build up in their arteries, a risk factor for heart attack and stroke. That study’s author, Dr. Barry Freedman pointed out, “We need to determine whether we should be targeting the same vitamin D level in blacks as whites, and better understand the cardiovascular effects of supplementing vitamin D in African-Americans.”
Here are some tips to guide your vitamin “D”ecisions:
(Osteoporos Int 2012; 23:2283–91; J Clin Endocrinol Metab 2010; 95:76–83)