© unknown
Der er en industri til mange milliarder, der er optaget af produkter, som bekæmper tegn på aldring, midler der gør huden blødere går kun lige så dybt som huden. Aldring foregår dybere — på celleniveauet — og videnskabsfolk har fundet ud af, at det at spise mindre kan sænke aldringsprocessen.

Forskningsresultater publiceret for nylig i Molecular & Cellular Proteomics giver et glimt af, hvordan indskrænkning af kalorieforbruget påvirker aldringsprocessen inde i cellerne. Forskerne fandt, at når ribosomerne — cellens proteinskabere — sænker deres aktivitet, så sænkes aldringsprocessen også. Den nedsatte hastighed sænker produktionen, men giver ribosomerne ekstra tid til at reparere sig selv.

"Ribosomerne er en meget kompleks maskine, lidt ligesom din bil, og den har regelmæssigt brug for vedligeholdelse for at erstatte de dele, som slides hurtigere," siger biokemiker ved Brigham Young University og den ledende forfatter, John Price. "Når hjul bliver slidte, så behøver du ikke smide hele bilen væk og købe en ny. Det er billigere at udskifte hjulene."

Så hvad får ribosomerne til at nedsætte funktionen? I det mindste for mus er det kalorieforbruget.

Delvist oversat af Sott.net fra How eating less slows the aging process
Price and his fellow researchers observed two groups of mice. One group had unlimited access to food while the other was restricted to consume 35 percent fewer calories, though still receiving all the necessary nutrients for survival.
"When you restrict calorie consumption, there's almost a linear increase in lifespan," Price said. "We inferred that the restriction caused real biochemical changes that slowed down the rate of aging."
Price's team isn't the first to make the connection between cut calories and lifespan, but they were the first to show that general protein synthesis slows down and to recognize the ribosome's role in facilitating those youth-extending biochemical changes.

"The calorie-restricted mice are more energetic and suffered fewer diseases," Price said. "And it's not just that they're living longer, but because they're better at maintaining their bodies, they're younger for longer as well."

Ribosomes, like cars, are expensive and important — they use 10-20 percent of the cell's total energy to build all the proteins necessary for the cell to operate. Because of this, it's impractical to destroy an entire ribosome when it starts to malfunction. But repairing individual parts of the ribosome on a regular basis enables ribosomes to continue producing high-quality proteins for longer than they would otherwise. This top-quality production in turn keeps cells and the entire body functioning well.

Despite this study's observed connection between consuming fewer calories and improved lifespan, Price assured that people shouldn't start counting calories and expect to stay forever young. Calorie restriction has not been tested in humans as an anti-aging strategy, and the essential message is understanding the importance of taking care of our bodies.

"Food isn't just material to be burned — it's a signal that tells our body and cells how to respond," Price said. "We're getting down to the mechanisms of aging, which may help us make more educated decisions about what we eat."

Source: Andrew D. Mathis, Bradley C. Naylor, Richard H. Carson, Eric Evans, Justin Harwell, Jared Knecht, Eric Hexem, Fredrick F. Peelor, Benjamin F. Miller, Karyn L. Hamilton, Mark K. Transtrum, Benjamin T. Bikman, John C. Price. Mechanisms of In Vivo Ribosome Maintenance Change in Response to Nutrient Signals. Molecular & Cellular Proteomics, 2017; 16 (2): 243 DOI: 10.1074/mcp.M116.063255