Of course, we're not actively swallowing the stuff, but the gums absorb it, and it's unavoidable that a bit will slink down the gullet from time to time. And given that most of us brush our teeth over 700 times a year, there's no shortage of opportunity to ingest ingredients better left in the lab. It's time to get crafty and create your own toothpaste that will leave your breath minty clean.

The most controversial of all the ingredients is fluoride. Although fluoride has been proven to cause neurotoxicity, very little published research has elaborated on acute fluoride poisoning and neurotoxicity in adults and children.

A study published in Neurologia showed that the prolonged ingestion of fluoride may cause significant damage to health and particularly to the nervous system. A report in a peer-reviewed open access journal published by the National Institute of Environmental Health Sciences performed a systematic review and meta-analysis of published studies to investigate the effects of increased fluoride exposure and delayed neurobehavioral development. The results confirmed toxicity to the brain.

Most people are quite shocked when they review the following info-graphic on fluoride levels in water and toothpaste: