Hi Dr. C,
I just read a newsletter saying that my vitamin D levels should be above 60 to help heal my thyroid. Do I need this much?
– Irene, Tallahassee, Florida
Great question. I do encourage Vitamin D testing and supplementing with Vitamin D3 to reach a blood level of 35-50 ng/mL.
Most studies do show that low levels of vitamin D may be a risk factor for developing autoimmune thyroid disease, although many do show no association. There is no clear link between vitamin D levels and thyroid cancer.
As to whether vitamin D helps those who already do have thyroid disease, the latest review showed that it may lower anti-thyroglobulin levels by about 30% for 3-6 months.
All the studies I found compared those who were vitamin D deficient against those who were not. Based on the study, deficient was defined as under 18-30 ng/mL.
No studies showed improved effects for those who were higher than 50 ng/mL.
The drawback with targeting blood levels over 60 ng/mL is that vitamin D is less protective against early mortality when it’s this high.