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I get sent this study every couple of weeks and wanted to write a thread about why I think it's problematic. https://twitter.com/AntiRacist_Sci/status/1288597295286620166
The study claims that low vitamin D levels among Black populations are not a problem because these populations have genetically lower levels of vitamin D binding protein, which means that the 'bioavailable' vitamin D is not significantly lower. https://www.nejm.org/doi/10.1056/NEJMoa1306357?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%20%200pubmed
Problem 1: This study uses race as a proxy for genes and we should never do that. There's a huge amount of genetic variety within racial groups because they're basically political, not biological. This is a good thread on this subject. https://twitter.com/kareem_carr/status/1270756761247629320
So it's going to take an extraordinarily strong study to convince me that we can learn anything about genetic nutritional requirements from racial groups. I am not willing to make general conclusions about this based on a single study of people in Baltimore.
Problem 2: I have no idea why only free vitamin D is considered bioavailable as many tissues can take up bound vitamin D. https://thorax.bmj.com/content/65/5/456
Problem 3: This paper is contradicted by later work that argues that their findings were due to an assay bias. I'm not at all qualified to adjudicate who's right here, but we shouldn't present the Powe paper as fact when there's continued debate. https://academic.oup.com/jcem/article/101/5/2226/2804833
To be clear I think that people often point to vitamin D deficiency as a way minimize larger systemic health threats to minorities, and I think that's wrong. The reason to care about vitamin D is that it might help a bit, and it's very easy to fix. https://shotwell.ca/posts/2020-05-23-race-and-covid/
