The source of chocolate is the seed from the cacao tree which has been cultivated for over three thousand years in Mexico, in Central, and in South America. The cacao seeds have a bitter taste, so the ancient peoples of those regions fermented them to bring out the flavor that we modern folk love so well. In fact the Aztec word xocolatl means something like bitter water. The Aztecs and their neighbors made beverages out of fermented cacao seeds. This is good news for seniors who are looking for ways to foster preemptive aging techniques to improve their senior health, because chocolate is full of flavanols similar to those found in red wine, apples, teas and so on.
In particular the flavanols in cocoa products have been shown to have a number of health benefits particularly in terms of cardiovascular health.  In addition they tend to enhance insulin sensitivity,  blood pressure, and cognitive function which are all important health issues for seniors.  The cocoa products have been shown to increase cerebral blood flow and brain activation.  This is very good news for seniors, because cocoa products taste good, they can improve your cardiovascular health and possibly make you smarter, too.