COLOGNE, Germany — Limiting the amount of food one eats, also known as “dietary restriction,” promotes a longer lifespan and robust health in both animals and humans. While that much is quite clear, scientists still don’t have a full understanding of why dietary restriction is so beneficial. Now, however, a groundbreaking new study is providing some potential answers. Researchers from the Max Planck Institute for Biology of Aging have identified a protein called Sestrin that appears to “mediate” and dole out the health benefits of eating less.
When study authors increased Sestrin levels in a group of fruit flies, the tiny test subjects lived longer. Sestrin also shielded the flies from the effects of a protein-rich diet. Diets including an excessive amount of protein appear to have a link to a shorter lifespan. In addition to all that, Sestrin also helped maintain stem cells located in the flies’ guts.
Recent research focusing on dietary restriction has revealed that the benefits of eating less aren’t so much tied to ingesting less calories overall, but more connected to the restriction of certain foods. Specifically, limiting both the intake of proteins in general, and their specific amino acids, is most important when it comes to reaping tangible health benefits from a dietary restriction regimen.
Sestrin’s affect on molecular matters
The research team says their study focused on Sestrin’s impact on the “TOR” signaling pathway. This cell-signaling system is known to play a big part in longevity and lifespan.
“We wanted to know which factor is responsible for measuring nutrients in the cell, especially amino acids, and how this factor affects the TOR pathway”, explains researcher Jiongming Lu in a media release. “We focused on a protein called Sestrin, which was suggested to sense amino acids. However, no one has ever demonstrated amino acid sensing function of Sestrin in a living being.”
All in all, the results of the experiment clearly indicate Sestrin works as a “novel potential anti-aging factor.”
“We could show that the Sestrin protein binds certain amino acids. When we inhibited this binding, the TOR signaling pathway in the flies was less active and the flies lived longer,” Lu continues. “Flies with a mutated Sestrin protein unable to bind amino acids showed improved health in the presence of a protein-rich diet.”
Remarkably, when Sestrin levels increase in some of the fly’s stomachs, those flies ended up living roughly 10 percent longer than their peers. More Sestrin in the gut also helped protect against the adverse effects of too much protein.
“We are curious whether the function of Sestrin in humans is similar as in flies. Experiments with mice already showed that Sestrin is required for the beneficial effects of exercise on the health of the animal. A drug that increases the activity of the Sestrin protein might therefore be in future a novel approach to slow down the aging process,” Lu concludes.
The study is published in Nature Aging.