First the free radical theory, then sirtuins, and now the ability of dietary restriction to extend lifespan is being thrown into question. Are there any universal biochemical aging pathways left? A recent paper in Ageing Research Reviews (sorry, its Elsevier . . . .) gives the results of a meta-analysis of the evidence for genetic effects on aging under DR. What Swindell found is that the lifespan extending effects of dietary restriction (DR) depend on genetic back ground and DR may not even work in wild type populations. I have been hearing rumblings behind the scenes that DR was in trouble and now the story might be coming out. The new study is written such that the contradictory data sets are not emphasised, but here is a quote from the discussion:
“An implication of these findings is that connections between DR and basic aging mechanisms may lack a universal character, and that greater attention to species-and genotype-specific effects will be valuable for developing a nuanced model of how DR impacts aging and longevity.”
In the last decade pretty much everything researchers in aging took for granted has been discredited. The bottom line is that research into aging is going through a period of overturning most of what we thought we knew making it the most exciting time to be a researcher in this field for the last several decades. If anyone is trying to tell you aging is almost solved, they are most likely selling snake oil. If you are curious what I think is going on then see my review in Myrmecology News (or here).