CW for the vegans, I'll be talking about canned fish in this comment
Check out those deenz, folks. Try and descend your snouts into a funky can of sardines this season. They're real good; rich in bio-available Vitamin D, rich in healthy fats and they got a lot of calcium too. Get some tasty sardines (ideally, with skin on and bones in), laid to rest in a fresh drizzle of olive oil and enjoy that little bite of the seas. I've started eating a bunch of canned fish (mostly herring and sardines, tuna isn't ideal) this winter and my skin is a lot better, as is the seasonal depression. Can recommend
it's nature's multivitamin, really