Biotin is also known as vitamin H, named for the German words "Haar" and "Haut," which mean hair and skin. This was due to the fact that even slight deficiencies cause hair thinning, skin rash or brittle fingernails. New research, just published in PNAS, now shows that some forms of severe neurodegeneration, like the frontotemporal dementia seen in Alzheimer's and Parkinson's, can directly result from lack of sufficient biotin. The authors discovered this by looking at fruit flies with dementia. Now, before anyone chuckles, fruit flies actually make a nice model of Alzheimer's or other diseases when they are given...