Longevity, calorie restriction, and red wine. From Scientific American.

There's a link to the article at the bottom of this post. I found it difficult to find four paragraphs that gave a good understandable synopsis, so I'll try to summarize it in my own words.

It has for some time been accepted knowledge in the scientific community that "calorie restriction" can extend the lifespan of organisms 30% to 50%. This is done by reducing caloric intake 30% to 40% while supplementing to make sure that other nutritional needs (vitamins, etc.) are met. The youthful part of the lifespan is also increased and diseases such as diabetes and cancer are forestalled.

This has been repeatedly shown experimentally to work in yeast, roundworms, mice, rats, and dogs. It therefore appears to be based on some fundamental mechanism that is likely shared by all multicellular organisms. A drawback is that it interferes with the reproductive process. And, in humans, that kind of drastic calorie restriction would most likely be intolerable.

It has been discovered that calorie restriction activates molecules known as sirtuins. Experiments have shown that these molecules are almost certainly what cause the extension of life and youthfulness.

Sirtuins can be activated by means other than calorie restriction. A substance found in red wine, resveratrol, activates sirtuins. Animals fed sufficient resveratrol (but not calorie restricted) experience the same life extension effects as calorie restricted animals but without the reproductive problems.

So, is this life extension in a pill?

http://sciam.com/article.cfm?chanID=sa006&articleID=000B73EB-3380-13F6-B38083414B7F0000&pageNumber=1&catID=2

Sirtuins can be activated by means other than calorie restriction. A substance found in red wine, resveratrol, activates sirtuins.