Science has known for some time that a calorie restricted diet will tend to add years to the life span. Laboratory research conducted with mice and dogs dating back to the 1930’s demonstrated life extension by as much as 40%. While scientists knew this to be true based on empirical research, exactly why a calorie restricted diet has this surprising effect remained a mystery.
Now science has identified a gene that appears to play a critical role in the link between calorie restriction and longevity. In a study run by the Salk Institute for Biological Studies in La Jolla, California, researchers have found that a gene identified in C. elegans roundworms, pha-4, may be a key link when it comes to understanding the mechanics of life extension. According to Andrew Dillin, an associate professor at Salk Institute, this discovery has important scientific implications … “we finally have genetic evidence to unravel the underlying molecular program required for increased longevity in response to calorie restriction.”
The gene in worms is associated with calorie restricted longevity. In humans three genes, part of the Foxa family, are similar to pha-4 and relate to the function of glucagon, a pancreatic hormone. The way the hormone works has important implications for this research. If you go on a fast, glucagon works essentially to increase blood sugar concentration and thus helps to maintain the balance of the body despite severe calorie restrictions.
The researchers arrived at their roundworm finding on pha-4 by a sort of knock-out process. They investigated the entire C. elegans genome and discovered 15 genes connected with DAF-16, a protein in the insulin/IGF pathway. Using a method known as RNA interference, researchers ‘knocked out’ genes one at a time to determine which of them interacted with DAF-16 in a manner that influenced the longevity of the worm. The only gene that had this effect was pha-4.
Most crucially, they also found that by increasing the pha-4 effect, they could in fact replicate what happens on a calorie restricted diet. This finding is so important that Dillin refers to pha-4 as “the cornerstone for defining the actual molecular pathways that respond to reduced food intake.”
Although the link in humans between calorie restriction and life extension has yet to be conclusively established, all the signs suggest that it is highly probable. One of the difficulties of course is that few people are prepared to survive on a restricted diet best suited to other-worldly ascetic types who don’t have to work 9 to 5, and deal with all of the associated stress. Science believes it may have the answer to this challenge.
The Salk research indicates that there are probably genetic “pathways” that help to modify the body’s response to a calorie restricted diet. That being the case, it is feasible that drug regimens can be developed in the future capable of mimicking this effect. This would mean that humans could enjoy some of the benefits of calorie restrictions, without actually having to subsist on a spartan diet.
Currently the research has expanded to include primates, and according to professor Dillin this research is showing a lot of promise. Primates are tending to exhibit the same life extension response to calorie restriction that was found in other test subjects.