Okay so I finally came back from the conference. His presentation was really interesting.
First of all, he wasn't critical of CR - he still emphasized that CR increased healthspan, though not necessarily lifespan. In fact, he said that increased lifespan could simply be a side effect of increased healthspan, and that the effect of CR is that you're more likely to stay very healthy all the way to the end when you'll simply "drop dead" (he even had a slide about that).
He also said that while the NIH study ruled out an effect of CR on increased mean lifespan, there was still some chance that CR could still increase maximum lifespan in the rhesus monkeys still living (but we'll only find out in 15 years). He also said that the monkeys still living on CR do seem to be much healthier than the monkeys not on CR. And he said that he was planning to collaborate with the Wisconsin group to try to really identify what was done differently between the studies that produced the different results. He also praised the design of the Wisconsin study and said that he doesn't doubt the results from the study.
Also - when you're talking about genetically hetereogenous animals - each strain has a different "set point" for what "ad lib" is and what "calorie restriction" is. That's why you see studies like Liao et al. (2011) where 1/3 of the CR mice died prematurely, 1/3 saw no effect on lifespan, and 1/3 saw increased lifespan under CR. CR for one strain of mice might be a "starvation" diet for another strain of ice. The Liao et al. 2011 results were actually confirmed by another 2011 (or 2010) study with similar results (although some of the strains that died early under CR in one of the papers did not die early under CR in another of the papers).
Couple of other interesting things: he didn't see any significant differences between the two strains on either IGF-1 or on cholesterol. He also had a few slides showing the effects of CR on two different strains of mice (in both strains, 20% CR produces beneficial effects on insulin, glucose, and insulin resistance - but 40% CR does not improve glucose/insulin beyond that).
With that all said, yes, there were some differences with the Wisconsin study. E.g. the Wisconsin animals were only fed food once a day. The NIH animals were fed twice a day.
He also made an interesting comment about how resveratrol actually helps with intermittent fasting since in intermittent fasting, cells experience a huge "nutrient load" on the days that an organism on IR binges.
Edited by InquilineKea, 21 May 2013 - 12:26 AM.
