Brains are delicate things…
This is a word that took on a specific meaning thanks to the Soil Association- no pesticides or fertilisers.
It gets conflated with ‘good’ and ‘natural’ and ‘beneficial for human society’, but there have been cases of producers steering clear of safer production methods that used artificial ingredients so they could say ‘100% natural.’
See Phil Lempert “How natural is ‘natural flavouring?‘ March 30th 2004 http://www.supermarketguru.com/page.cfm/6046
See also: Nature and Nulture