Here's an interview with one Cynthia Kenyon, whose research with worms indicates that hormones hold the key to curing aging:
We found that mutations that lowered the activity of a single gene, called daf-2, caused the worms to live more than twice as long as normal. We showed that their long lives weren't caused by changes in feeding or reproduction - two boring possibilities. But the best thing was that the long-lived worms remained active and healthy long after normal worms were decrepit or dead. They were like 90-year-old people who looked like 45-year-olds.
The daf-2 gene encodes a hormone receptor similar to the human receptors for insulin and IGF-1. So hormones control ageing. They speed it up. Then there are many genes "downstream" of this receptor that do lots of different things. Some of them code for proteins that protect animals from all sorts of stresses, chaperones that help other proteins fold correctly, and antioxidant proteins such as catalase and superoxide dismutase. Then there are those that encode proteins that kill bacteria, and metabolic genes. But you have a single hormone receptor, the IGF-1/insulin receptor, and a transcription factor commanding between 50 and 100 genes that directly affect the ageing process. It's like an orchestra conductor coordinating the flutes and the cellos and the French horns. That's how you get these big effects on lifespan.
Kenyon believes that controlling insulin levels may be key to prolonging human life. Her recommended lifespan-enhancing diet sounds a lot easier than caloric restriction, and in fact sounds a lot like a diet much discussed in the blogosphere:
I eat a diet that keeps my insulin levels low. So, for example, at breakfast I have bacon and eggs with tomatoes and avocados. It's bit like the Atkins diet. I don't actually know if I eat fewer calories, but I feel great and I weigh what I did in high school. I certainly wouldn't want to be hungry all the time, but I'm not, I'm never hungry. I tried caloric restriction just for two days but I couldn't stand it, being hungry all the time.
I've been on Atkins (theoretically) for quite a while, but my progress is slow because I cheat so much. I'm going to have to do some serious rethinking of that strategy.
UPDATE: Randall Parker reports that cholesterol,
as well as insulin, may have a significant role to play in fighting aging.