There's a greentext that's been floating around for a while, I don't know the original author and can't remember the exact text to search for it, but it's along the lines of

> my deepest fantasy is that one day I'll be in the hospital for some random thing, they'll take blood for some test, and then when they read the results, their eyes will go wide and they'll call for a consult. The other doctor will read the results and say "you don't have the nutrient?! How do you live? You're so brave". They give me a shot, and just like that, I'm able to conduct myself in society, understand social cues, hold my attention on anything i want for any length of time, etc

... so perhaps the Nutrient is a product of a gut bacterium.