I treat “grain” as “wheat/gluten” in game. So new recipes and items. AFAIK flour in game is not fortified (crafted vs store purchased in game is the same). Also cornmeal is treated the same as “veggy”, which messes up the actual vitamins of real corn flour. So I will need to see if I can add a “grainOther” alternative to the “wheat” flag.
So I can go in and adjust them to better IRL versions. I can take out the fortified variety but that would be a lot more work (making alternative items/recipes). Rice flour also has different vitamins. But most things will be eaten mixed in something, as the player will not be eating flour alone. 
AFAIK current game puts cornflour items into the “wheat” category, when cooked in foods also allowing wheat based flour.
So I have already divided out “wheat” and “cornflour” [“cornmeal” in game]. I may just go with a mixed variety, and fudge the vitamins (for the mod, not for the game, as I probably won’t have time to go through every vitamin/nutrition value).
The game also for some reason notes cornmeal as 2 for nutrition (similar to calories in game I think), but normal flour is 1. it has twice the fat content, but 1% vs 2% is nothing
… carbs is about the same, calories is near identical!
@TheMurderUnicorn Yep, that’s what this mod does. Seperate them out. I’m still to decide if I just want to shove in “mixed GF flour” as coding all the recipes by hand (I’d love a GUI tool to copy/paste entire data set XD ) would take forever doing acorn, rice, buckwheat, oats, almond, corn etc.
I have left out “pastas” as I have not tried making these IRL, and as said, without gluten most things do become crumbly (as normal rice and corn dishes avoid this by allowing the natural starches to provide some texture or binding, however this does not help with baked or other types of cooking).