Tolerable Upper Limit of Vitamin D is 4,000 IU...even for Children

In 2010, the Institute of Medicine (IOM) raised the safe upper limit of vitamin D from 2000 IU to 4000 IU per day for individuals older than 9 years. Many people are now using 4,000 IU in the winter after discovering that 2,000 IU is insufficient to maintain their blood level within the acceptable range (75nmol/30ng)...much less the levels of 100-150nmol (40?60ng) recommended by a panel of 41 vitamin D researchers and medical practitioners.

Have your vitamin D blood level tested and then supplement to reach an optimal level. How difficult is that?!