Both?
I'm adverse to saying that anything "natural" is beyond preventative, and I would suggest looking at the Alz and/or Park treatment protocols at lef.org as a place to start.
I agree with this 100%. From personal experience with my mother and grandmother, once the onset of dementia has begun, just getting the afflicted person to eat half-way adequately, let alone take anything extra, even prescribed medication, often becomes a monumental task. Unfortunately, the progression of the disease can usually be correlated with an increased rate of overall weight loss due to an increasing loss of appetite and/or an inability to taste anything except extremely sweet ( or extremely bitter or sour) foods.
Having said that, there is a U.K. journalist, Oliver Gillie, who suggests a correlation between low levels of Vitamin D as a major contributor to the onset of dementia, Parkinson's disease, diabetes, and a host of other neurological disorders. He has interviewed a number of prominent European doctors who have reviewed various epidemiological data as well as conducted their own research on the matter. Keeping an open mind on the subject, his treatise certainly is thought provoking:
http://www.direct-ms.org/pdf/VitDPopularArticles/GillieVitDArticle.pdf
Good luck. As for natural approaches, my only advice is to find things that she will eat and drink, regardless of their nutritional content or lack thereof, and try to keep her appetite stimulated. In the last couple of months before the death of my mother, I would melt ice cream and blend it with the high protein/high carb version of Ensure, and let her sip it through a straw while I held it. At the end, this was the only thing that she would willingly ingest.
