I've been doing a little research about the ingredients in the available toothpaste options for sensitive teeth – they all contain colours and flavours, and about half also contain two benzoate preservatives (which give me throat clearing/coughing for at least an hour afterwards). Most of them contain Potassium Nitrate as the active ingredient. I think this chemical is causing me to feel extremely unmotivated, disinterested in life, sometimes depressed.– by email, Vic. (Potassium nitrate is preservative 252, one of our nasty additives to avoid. It is even used in a particular brand of sensitive toothpaste labelled rather misleadingly "no added preservatives". See the Nitrates factsheet. See also a Nitrates - Alzheimers link in Research, Failsafe Newsletter #61. For prevention of sensitive teeth, see http://www.saveyoursmile.com/healtharticles/sensitiveteeth.html)