Heirloom vegetables grow more slowly and spoil much more quickly than modern crops. This is because modern crops have less nutritional value - https://jeroenvanbaar.substack.com/p/data-dispatch-4-the-falling-nutritional
That article recommends eating a better diet. Sure. Seems a bit idealist. Here's some more actionable advice: everyone should take a multivitamin and magnesium glycinate. If you live somewhere that gets a winter take vitamin D too.
I'm speaking from experience here, I used to get sick every winter and my skin would get so dry it would crack and bleed. Take your vitamins.
Are there any countries that do serious biomedical science based regulation of vitamins? I've heard that for most people who are eating a varied diet and aren't facing, like, idk, a diet made up of one or two elements or grown in severly depleted soils vitamins aren't necessary.