Monday, September 3, 2012

Caloric Restriction and Longevity, Revisited

Does severe caloric restriction really lead to longer life? Back in 2009, a research study from the University of Wisconsin (performed with primates) suggested that it does. But now a second study, also in primates, seems to contradict that finding. The latest study, from the respected National Institute on Aging, began 25 years ago and is still ongoing. But the data so far show no positive effect of caloric restriction on longevity. These findings are corroborated by experiments in 41 different strains of mice that showed that caloric restriction has little or no effect on life span overall – it increased length of life in some strains, had no effect in others, and actually reduced lifespan in some strains.

Why the contradictions? No one is sure, but certainly there were differences in how the two primate studies were done. The initial study omitted some primates from inclusion in the final statistics, arguing that they did not die from “age-related” causes. There were differences in diets used as well.

It’s still possible that caloric restriction does lead to some health benefits other than simply length of life. Indeed, in the most recent primate study, caloric restriction did seem to lower cholesterol and sugar levels in some of the monkeys. But the current data are not particularly encouraging when it comes to the efficacy of caloric restriction in extending life span.

For more on this subject, go to a previous blog post titled "Caloric Restriction and Longevity."

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