A new discovery helps explain why the “Alzheimer’s gene” ApoE4 is such a risk factor. It appears that ApoE4 causes a dramatic reduction in SirT1, an "anti-aging protein" that is targeted by resveratrol (present in red wine). This reduction in SirT1 was associated with a change in the way the amyloid precursor protein (APP) was processed. Moreover, there was evidence that ‘bad’ tau and amyloid-beta could be prevented by increasing SirT1.
http://www.eurekalert.org/pub_releases/2013-10/bifa-mar101613.php