system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do fruits and vegetables have more vitamins than other foods?
gpt
Not to be too flippant, but the reason why fruits and vegetables have so many vitamins is because fruits and vegetables have so many vitamins. Let me explain… evolutionarily speaking, these are things the body needs but can’t produce. Many are things our distant ancestors could produce, but can’t anymore. The reason is that they are plentiful in the easier-to-get food and can be absorbed from them, so losing that ability is not something that would cause you to not be able to survive to childbearing age or raise children. There are other genetic issues people can have that cause the body to not be able to produce certain things, but because our common foods can’t supply them either (or our bodies can’t absorb them through the gut), they are considered genetic diseases instead of the missing things just being labeled “vitamins”. 

So the reason these foods have so many chemicals we consider “vitamins” is that they were plentiful and thus our bodies didn’t have evolutionary pressure to keep making it ourselves.