[alicorn]

I am lazy and did not read the study, sorry. But nowhere in the comments I see discussion related to whether it somehow accounts for dietary variance in vitamin D intake via fortified products. In Sweden, for example, because we are so far north, milk is routinely fortified with vitamin D. So even if a person has a genetic variance for low vitamin D, they will still be supplemented without actively doing anything, as long as they drink milk. On the other hand it stands to reason that if foodstuff fortification had a significant effect on vitD levels in population AND vitD had significant effect on immunity / severity of covid-19 then Sweden would have statistically significantly lower covid-19 infection and mortality rates than countries where food fortification with vitD is not practiced. Afaik that is not the case, otoh there is an insane amount of confounding variables so it might not be possible to assess such an effect in any scientifically valid manner.

[zepearl]

Interesting post for me in general (didn't know that Sweden did that "enrichment" + destroys at the same time my idea of "milk" just being "milk").

In general I would think that if there are countries that are not poor in relation to vitamin D, then it would be Sweden & Norway, as I understand that fish does contain a lot of vitamin D (random hit here: https://www.healthline.com/nutrition/9-foods-high-in-vitamin... ) (at the same time I'm subjectively assuming that people in Sweden & Norway & other nordic countries eat a lot more fish that others) => I'm therefore conflicted: if that's correct, assuming as well that the population eats fish (relatively often), then why enrich milk with extra vitamin D?

[alicorn]

Just Sweden does not eat an unreasonable amount of fish (see https://ourworldindata.org/grapher/fish-and-seafood-consumpt...). According to press release by Arla (the largest Swedish milk products company by far) some years ago (see https://www.arla.se/om-arla/nyheter-press/2015/pressrelease/..., in Swedish), there was a national study done by the government organization that controls foodstuffs which identified a large risk for vitamin D deficiency in general population, perhaps despite fish eating and law was passed making enrichment mandatory. So they are enriching.

Edit: removed sidenote about cooperation between government and private companies, since it seems that there is an actual law governing this stuff. Almost all milk, milk-like and fatty products (such as margarine), except cheese, must be enriched (see https://kontrollwiki.livsmedelsverket.se/artikel/448/livsmed..., in Swedish).

Edit++: Apparently data from the national study about food habits is available via an API which I think is super cute, see https://www.livsmedelsverket.se/om-oss/psidata/apimatvanor (also in Swedish, but hey, Google Translate is your friend)

[zepearl]

Puah - ok, that's surprising, at least for me :)

Thanks!