A study I posted on my Web site five years ago explained how the presence of a heavy metal like aluminum in tap water can increase your risk of dementia and Alzheimer's disease. French researchers have found high concentrations of a simple natural element -- silica -- can protect patients from such exposure.
The results stemmed from an offshoot of an osteoporosis study that included some 7,600 women older than age 75 from five French cities whose mental acuity was measured at the start. Patients recorded their intake of bottled water versus tap water and data was collected on the components of the water they drank from local companies.
During the first phase of the study, researchers discovered women with normal or higher brain functioning also consumed a higher amount of silica every day. A second phase, following up with patients from one city seven years later, found those who succumbed to Alzheimer's were almost three times more likely to have a significantly reduced daily intake of silica than those who didn't have it. That's why researchers believe silica to be a natural antidote to aluminum which has been previously linked to the formation of plaque in the brain.
You can add that to the growing list of natural safeguards I recommend for preventing Alzheimer's disease that don't require taking a magic pill:
American Journal of Clinical Nutrition, Vol. 81, No. 4, April 2005: 897-902
Reuters April 11, 2005