For those who received chocolates at Christmas

A Few Squares Of Dark Chocolate A Day May Stave Off Artery Hardening In Smokers

The above story seems to indicate a pretty remarkable effect of the consumption of dark chocolate, at least in smokers:

"After two hours, ultrasound scans revealed that dark chocolate significantly improved the smoothness of arterial flow, an effect which lasted for eight hours. Blood sample analysis also showed that dark chocolate almost halved platelet activity. Antioxidant levels rose sharply after two hours.

White chocolate had no effect on endothelial cells, platelets, or antioxidant levels.

Dark chocolate has more antioxidants per gram than other foods laden with the substances, such as red wine, green tea, and berry fruits, say the authors, who suggest that the beneficial effects of dark chocolate lie in its antioxidant content.

"...Only a small daily treat of dark chocolate may substantially increase the amount of antioxidant intake and beneficially affect vascular health," conclude the authors. "

One thing to note, though, is that this was very dark chocolate (74% cocoa solids), and from what I can gather most commonly sold dark chocolates are maybe around the 30 to 40% mark. I did try a 70 or 80% one from a specialty shop once, and it was rather on the bitter side. I think Lindt might sell a very high proportion one too; maybe it tastes better.