E-numbers are shortcodes used in the European Union and a few other regions to label food additives that have been evaluated and authorized for use by the European Commission [1]. Every E-number has been assessed for safety by the European Food Safety Authority (EFSA) — the 'E' literally stands for 'Europe' [2].
The system makes labels shorter but also more intimidating. The codes don't, by themselves, tell you anything about safety or naturalness.
Perfectly normal things have E-numbers: • E100 = curcumin (from turmeric) • E300 = ascorbic acid (vitamin C) • E330 = citric acid (the sour in lemons) • E440 = pectin (the gelling agent in apples and citrus)
Others are more synthetic and worth knowing about: • E102 = tartrazine (Yellow 5) • E407 = carrageenan • E621 = monosodium glutamate (MSG) • E951 = aspartame • E133 = Brilliant Blue FCF (Blue 1)
The number itself isn't the issue — knowing what each one IS lets you decide. Don't avoid 'E-anything' as a blanket rule; that would eliminate vitamin C too. Use the codes to look things up, not to fear them.