Not all E additives are anything we synthesize. Some of them are natural products with a convenient code.
http://www.laleva.cc/food/enumbers/E100-E110.html
E100
Curcumin, turmeric
E101
Riboflavin
Riboflavin, also known as Vitamin B2,
If we labelled roses as Eewh96 it would still be a pleasant red coloured flower with spiky bits and potential health hazard. Not intended for ingestion...
whole list here
https://en.wikipedia.org/wiki/E_number#E100.E2.80.93E199_.28colours.29
I'd be more worried about man made stuff like dioxins, heavy metals, pesticides... but food additives tend to be fine.
If you ate this red, you've done some entomophagy.
E120 Cochineal, Carminic acid, Carmine (Natural Red 4) Crimson
probably red colouring in your m&m's...
https://en.wikipedia.org/wiki/Cochineal
Carminic acid is extracted from the female cochineal insects and is treated to produce carmine, which can yield shades of red such as crimson and scarlet. The body of the insect is 19–22% carminic acid.[9]