[derefr]

People have been eating imperfectly for millenia and keeping on nevertheless. How many billion (trillion?) Chinese peasants, across history, do you think ate only rice their entire lives?

Sure, said peasants probably had vitamin A deficiency—but they managed to live long, mostly-healthy lives despite that. Which is my point: we don't need to get "food" perfect in order to ensure that 10x as many people as today can live "long, mostly-healthy lives." It's not unethical to feed starving people food that's missing some micronutrient we aren't yet aware of, because they'll still be better off than if they were starving. The human body is hardy.

[iopq]

Those peasants also ate a lot of vegetables because they couldn't afford meat. Vegetables that have beta-carotene, like bok choy.