Aspartame

the chemical can disrupt amino acid metabolism and structure, degrade nucleic acids, and interfere with the function of nerve cells and hormonal systems.

It also appears to change the concentration of certain neurotransmitters in the brain.The researchers also noted that aspartame appears to cause excessive signaling of nerve cells, and nerve cell damage or even death..

Source: http://momsword.org/index.php?option=com_content&view=article&id=7134:aspartame-is-bad-for-body-natural-is-better&catid=1:latest-reviews&Itemid=50