In 2010 the Institute of Medicine updated the recommended daily allowance (RDA) of vitamin D from 400 IU to 600 IU per day for adults up to age 70, and 800 IU per day for adults 71 years and older. While this update was a (tiny) step in the right direction, many experts think it comes up far too short. The recommendations are based on the ability of 600 IU vitamin D daily to raise blood levels of vitamin D to 20 ng/mL, which the IOM thinks of as “sufficient.”
To the contrary, many health experts consider at least 50 ng/mL to be an optimal level of vitamin D, and it takes more than 600 IU daily to reach that level. A recent study published in the American Journal of Cardiology brings this issue to light. “Many previous studies on vitamin D supplementation have used doses of 400 to 800 IU, which might not be adequate to ensure optimal serum [blood] levels, with more appropriate daily supplement doses suggested as 1,000 to 2,000 IU,” stated the authors of the study.
They tested vitamin D levels in the blood of over 10,000 participants, average age 58. Participants were classified as deficient if their levels were 30 ng/mL or lower. (You can already see the discrepancy between experts—IOM states levels over 20 ng/mL as sufficient.) The average vitamin D level of participants was 24 ng/mL. In other words, 70 percent were considered deficient.
The most important finding of their study, however, was that the risk of all-cause mortality (that is, the risk of death by any cause) was 164 percent higher in those people with vitamin D deficiency. Remember, that’s 70 percent of them. Vitamin D supplementation was associated with better survival, especially in patients with precious deficiency. “Our study suggests a significant association of vitamin D supplement use and improved survival in deficient subjects, supporting the potential benefit of this intervention.” Vitamin D deficiency was also associated with increased risk of cardiovascular-related conditions such as high blood pressure, heart disease, and diabetes.
If you haven’t had your vitamin D level tested, ask your doctor about it. Vitamin D deficiency, or insufficiency, is associated with a wide range of chronic health conditions.
I read an article about children going back to school and that they should have vitamin D to keep them healthy…it said 1000 units to each 25 pounds that they weighed. Are other vitamin amounts based on the weight of a person also and is this the correct amount that we need? I have been watching PBS with you on there also…such great info. Is the big book you have taken two years to publish going to be offered on your site? and when?