The informative and useful InfoAging website is worth visiting every so often to catch up on their schedule of updates. Here are a few from the past month:
Infoaging: There has been concern regarding the implications of people living forever. In your opinion, is there a certain point beyond which people cannot age or is it possible for lifespan to be prolonged indefinitely?
Dr. Barzilai: Centenarians die of the same causes as everyone else - only approximately 30 years later. This suggests that once we find the right switch - a longevity gene - we can increase the average life expectancy to 100 years. Getting beyond that, however, is something we don't yet know much about.
"Solid tumors have a very ill-defined and poorly developed blood supply," Giaccia explains. In fact, many tumors become hypoxic, and experts have long noticed that hypoxic tumors are much more aggressive and prone to metastasis than more oxygen-rich cancers.
The Stanford group discovered that the hypoxic state triggers a very high expression of the gene that produces the lysyl oxidase enzyme. That's important, because lysyl oxidase aids metastasis by building the collagen "matrix tracks" that cancer cells travel on as they migrate to other sites.
But would inhibiting lysyl oxidase curtail this migration? ... While mice with normal cancer lines went on to develop metastatic cancer, mice with lysyl oxidase-disabled tumors showed no such spread.
Whether CR can actually extend the natural limits of the human lifespan, however, is debatable. "It's my personal opinion that caloric restriction isn't actually going to have much of an effect on human lifespan," says Mobbs. "Over the millennia, there have been many, many people who have been subjected to caloric restriction, probably most or all of their lives. Many had it imposed on them, but there were also religious, monastic people who fasted all the time. Among all of them, there has never been any substantiated report - really, almost no claim at all - that such people live much longer than everyone else. Even the present-day Okinawans, who have exactly the kind of diet we're talking about, don't live beyond the maximum known human lifespan." However, Okinawans, on average, do live longer than any other group on the planet, and they suffer from far less heart disease, cancer, and neurological diseases such as Alzheimer's and Parkinson's as they age.
Mobbs is a calorie restriction skeptic in the manner of Michael Rose and John Phelan or Aubrey de Grey, then. Given the increase in healthy life span and reduction of chronic disease in just the past hundred years, I don't think the quoted text above is a very robust argument - but there are better, more convincing arguments out there, such as those put forward by the other researchers mentioned above. As the article notes, the jury is still out on extension of maximum life span - well proven for animals - in humans, but the weight of evidence is overwhelming for greater health and resistance to age-related disease.