I don't know how true it is, but I remember learning back in elementary school there were cases of Europeans dying from food poisoning after eating some Inuit dishes without proper "training".

Doesn't seem that farfetched. I mean there are well known genetic conditions which cause you to become mentally retarded, if not death, if you eat certain foods (eg PKU). Then there's protective genetic conditions like gilbert's syndrome, mutations which give lactose tolerance for life, hereditary haemochromatosis...

It should be obvious by now that subtle genetic differences can hold a huge influence in regards to what a "healthy" diet for someone is. IMO, there isn't enough research being done on such matters.

High-fat diet made Inuits healthier but shorter thanks to gene mutations, study finds

https://www.ox.ac.uk/research/high-fat-diet-made-inuits-heal...

There are other reasons, but Inuits also don't live long compare to others. https://www.reuters.com/article/us-inuit/inuit-lifespan-stag...