Insights from the caloric restriction diets experiment with wild rodents

Caloric restriction (CR) diet has started to become popular or infiltrated into our modern society. In the 1980s, One of the frontier CR researchers, Roy Walford, attempted to plant the seed of CR through his book _The 120 Year Diet: How to Double Your Vital Years. _The harsh temperance on the lifestyle he proposed did not let him yield success in popularizing CR, and he died at the age of 79, failing to accomplish the 120 years achievement as he wrote in the book.

Numerous reports showed that CR improves life span in multiple organisms; rodents, worms, monkeys, etc. Despite those promising data, one of the key questions that remain unsolved is the uncertainties and limitations in translating laboratory animals' results into humans. The artifacts introduced by the laboratory environment may create bias on the effect of CR on lifespan, namely the selection bias of rodents with properties of rapid growth and robust production, which enables experiments done effectively in a short period of time.

One report(1) tried to tackle this issue by performing CR experiments on wild rodents instead of laboratory breed rodents. Strikingly, they found out that they could not recapitulate the beneficial effect of CR on lifespan with the use of wild rodents. The mean longevity between the ad libitum(AL) group and caloric restriction(CR) group is of no statistical significance (FigA), 888.5 ± 48.7 days (AL)compared with 870.6 ± 67.4 days (CR). Yet, throughout the experiment, the six longest-lived rodents are all in the CR groups.

Taking these together, the strong evidence of CR increasing lifespan is still lacking. Special attention is needed towards the anti-aging diet introduced by the propaganda.

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Ref1:https://onlinelibrary.wiley.com/doi/10.1111/j.1474-9726.2006.00236.x

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