And different populations evolutionarily "fine-tuned" in environments with different availabilities of various foodstuffs. While many dietary requirements are common to all humans (e.g. we lost the ability to synthesise vitamin C, making us all susceptible to scurvy), some are specific to individuals and (genetically-related) families.

Diet is one of the very few places where your genetic ancestry actually matters – although your gut microbiome, which evolves faster (https://doi.org/10.3389/fmicb.2014.00587), may not share quite the same ancestry as your human cell tissue.