N-acylethanolamines Required for Calorie Restriction
Another part of the biochemical mechanisms of calorie restriction is uncovered in nematode worms: "The study [was] conducted on Caenorhabditis elegans (nematodes or roundworms), which are a widely accepted model for human aging research. ... Not only have we been able to identify some of these molecules for the first time in the worm, but we have also been able to show they act as a signal of nutrient availability and ultimately influence the worm's lifespan. What makes this important is that the same molecules are present in both humans and C. elegans, so these molecules may play similar roles in both organisms. ... The molecules identified in the new study are N-acylethanolamines (NAEs), a group of signaling molecules derived from lipids that help indicate nutrient availability in the environment and maintain an animal's internal energy balance. [Researchers showed that] NAE abundance in the worm is reduced during periods of dietary restriction, and that NAE deficiency in the presence of abundant food is sufficient to extend the animal's lifespan. ... It is well known that if you put C. elegans on a restricted diet, you can extend its lifespan by 40 to 50 percent. However, we were amazed to see that if you add back just one of these NAE molecules, eicosapentaenoyl ethanolamide, it completely abrogates the lifespan extension. ... Importantly, this particular NAE is similar to endocannabinoids in mammals, which regulate many different physiological processes including nutrient intake and energy balance, as well as inflammation and neuronal function."
Link: http://www.eurekalert.org/pub_releases/2011-05/sri-srs050511.php
There is a little more information in author Gill's research proposal at -
http://www.labome.org/grant/r01/ag/endocannabinoid/signaling/endocannabinoid-signaling-and-aging-7864405.html
It speculates that increasing activity of the fatty acid amide hydrolase enzyme might reduce endocannabinoid (EC) levels, and possible extend longevity.
Since the EC system has many beneficial effects, modifying it could be complicated. It would be interesting to know if comparison of EC activity has been done between species, or correlated to human life span.
These findings are difficult to bring in line with human data and data on palmitoylethanolamide's actiom as an inhibitor of inflammatory cacades and of slow or low grade inflammation, as present for instance in diabetes. But then there are many NAEs, and PEA probably stands out as a very specific one!