I heard that flour (fluoride) can have a negative effect on the brain, is this true? if it's true, should you avoid using toothpastes like zendium?

Controversial: The blog site opinions raise concern that fluoride can assist in toxic deposits of aluminum and other metals within the brain resulting in eventual Alzheimer's disease. The city of Portland, Oregon, has taken fluoride out of drinking water. Negative effect of fluoride remains controversial, but no clearcut benefit for adults has been proven either. Hope dental colleagues chime in.