Question

How much vitamin D is enough?

A 25(OH)D (calcidiol) level above 30 nmol/l is sufficient to prevent severe hypovitaminosis D, and in most cases osteomalacia and rickets. 1-3

A calcidiol level of 50 nmol/l may be considered adequate 4 

nmol/LVitamin D Status
>50Sufficient for almost the whole population
30-50May be inadequate in some people
<30Deficient

Table adapted from National Osteoporosis Society. Vitamin D and bone health: A practical clinical guideline for patient management. April, 20131

References

1. National Osteoporosis Society. Vitamin D and bone health: A practical clinical guideline for patient management. April 2013.
2. Zittermann A et al. Putting cardiovascular disease and vitamin D insufficiency into perspective. Br J Nutr 2005;94:483-92.
3. Souberbielle JC et al. Evaluating vitamin D status. Implications for preventing and managing osteoporosis and other chronic diseases. Joint Bone Spine 2006;73:249-53.
4. Pearce S & Cheetham T. Diagnosis and management of vitamin D deficiency. BMJ. 2010; 340:b5664.