Forget about vitamin D RCTs. They are mostly poorly designed, conducted and analyzed.
Instead, rely on observatational studies related to 25(OH)D.
My response to Demay et al. Endocrine Society Guidelines.
Grant WB, Wimalawansa SJ, Pludowski P, Cheng RZ. Vitamin D: Evidence-Based Health Benefits and Recommendations for Population Guidelines. Nutrients. 2025 Jan 14;17(2):277. doi: 10.3390/nu17020277
Forget about vitamin D RCTs. They are mostly poorly designed, conducted and analyzed.
Instead, rely on observatational studies related to 25(OH)D.
My response to Demay et al. Endocrine Society Guidelines.
Grant WB, Wimalawansa SJ, Pludowski P, Cheng RZ. Vitamin D: Evidence-Based Health Benefits and Recommendations for Population Guidelines. Nutrients. 2025 Jan 14;17(2):277. doi: 10.3390/nu17020277
Hi, William -- nice to hear from you especially all these years since our letter that JAMA butchered in 2004 https://jamanetwork.com/journals/jama/article-abstract/199799.
Agreed that many of the RTCs are horrible, the worst was the 2021 JAMA study wherein they delayed treatment by 2 weeks and then concluded that vitamin D did not work. https://www.academia.edu/45159442/Call_for_Retraction_preprint_infographic_Effect_of_a_Single_High_Dose_of_Vitamin_D3_on_Hospital_Length_of_Stay_in_Patients_with_Moderate_to_Severe_COVID_JAMA_2021
Several of the RTCs from Spain were good and I reviewed them toward the end of this video. https://healthythinking.substack.com/p/video-review-the-importance-of-vitamin