Essay

Vitamin D, Dementia, and Rhonda Patrick’s Claims

An evidence check on Rhonda Patrick’s vitamin D and dementia claims, observational studies, confounding, and supplement certainty.

Indexed essay May 21, 2025 By Devin Teichrow sciencedementiavitaminsvitamin Dscience communicationsupplements

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Wellness Claims

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vitamin D dementia Rhonda Patrick

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By Devin Teichrow. Published May 21, 2025.

Overview

An evidence check on Rhonda Patrick’s vitamin D and dementia claims, observational studies, confounding, and supplement certainty.

By now, more than 200,000 people on Twitter and over 30,000 on YouTube1 have seen the new video of Dr. Rhonda Patrick explaining how vitamin D supplements can cut your dementia risk by 40%2. That’s a bold, hopeful claim based on an observational study of over 12,000 people. And I think she means well. But how true is it?

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