You're never going to get sensible dietary advice on HN.
Get sun. If you can't get sun you should eat a variety of food that contains vitamin D. If you can't do that, you should take a supplement. Take the supplement at the same time as you eat a meal, preferably a meal that has some fat.
Get sun. If you can't get sun you should eat a variety of food that contains vitamin D. If you can't do that, you should take a supplement. Take the supplement at the same time as you eat a meal, preferably a meal that has some fat.
Here's the advice for England:
https://www.nhs.uk/live-well/healthy-body/how-to-get-vitamin...
https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-...