The only real medical recommendation made for the general population (i.e. those without a deficiency) in the Northern hemisphere is to supplement vitamin D if your diet is an inadequate source of this. It's quite possible to get enough in your diet, depending on where you live and if you prioritise your diet. With the winter months coming on it's one of the few I'd recommend getting your blood levels checked for, and maybe replacing if needed. If you work inside 9-5 it'd be quite easy to be deficient due to lack of sun.
I'm totally speaking from a place which probably overvalues vitamin D though, as a general practitioner (family doctor) who had a background in orthogeriatrics, where you can really see the harms of low vitamin D in the older population's bone health.
Also fish oil, Dan John loves that fish oil - but you can get that with a good varied diet including oily fish and it will be much more enjoyable. He has a pretty aggressive suggestion for a regimen in Easy Strength, which I wouldn't be keen to follow, but he knows a lot more about lifters and football players than I do!