Numerous studies have shown that caloric restriction can extend the lifespan of a variety of organisms, from fruit flies to baboons. However, usually this extra lifespan comes at the expense of being able to reproduce. Researchers at Washington University in St. Louis recently made an interesting finding, however – adding the amino acid methionine preserved the egg-producing ability of calorie-restricted fruit flies along with lifespan.
At first glance, the finding seems to contradict other studies, which have found that reducing methionine in a normal diet would extend lifespan. Not so, say researchers:
“There’s a sort of asymmetry in the relationship” between methionine levels and calorie counts, Piper says. “When food is low, lots of methionine is OK. When food is high, reducing methionine can lengthen lifespan.”
But other researchers who study aging and calorie restriction aren’t so sure that balancing amino acids will have the same effect in humans and other mammals.
Fortunately for people like me, who have no intention of restricting our calories to gain a longer lifespan, these findings may lead to methods that provide the benefits of CR without making humans dramatically cut down on what they eat:
“The idea that only calories are important is basically falling apart,” Fontana says.
Piper and his colleagues don’t know what the correct amino acid balance might be for humans, and he says it would be a nearly impossible feat to adjust people’s diets to get just the right mix. Instead, the team is investigating how tweaking amino acid content in the diet affects cells. If the researchers can identify pathways affected by amino acid imbalances, they might be able to design drugs or other therapies that could give the benefits of caloric restriction without cutting calories.
(H/T Instapundit. Fruit Fly photo courtesy of Flickr user upyernoz.)