My father told me of a story where a friend's sister had regularly given her child bottles of Ribena to suckle on. For those in the USA and other countries where that's not a thing, it's essentially a drink made from highly concentrated blackcurrant syrup (plus copious amounts of sugar), which you're meant to dilute with 5-6 units of water to each unit of syrup.  The child was given these bottles every day, completely undiluted! The child's teeth were completely rotted out by the age of five, and the Department of Community Services was called in to remove the child because of this, in addition to other evidence of neglect that they had collected.