Eating less has already been linked to longer lifespans in worms, flies, mice and monkeys – and now scientists think they know why.
A new study suggests that cutting calories while maintaining a balanced diet slows the ageing process in mice, at a cellular level.
The key to the phenomenon? Ribosomes: the cell’s protein makers.
Cutting calories in the mice’s diets was shown to slow the activity of ribosomes, slowing the ageing process too. The reduced speed lowers protein production, but gives the ribosomes more time to repair themselves, researchers found.
“The ribosome is a very complex machine, sort of like your car, and it periodically needs maintenance to replace the parts that wear out the fastest,” said Brigham Young University biochemistry professor and senior author John Price.
“When tires wear out, you don’t throw the whole car away and buy new ones. It’s cheaper to replace the tires,” Price added.
The study, published in Molecular & Cellular Proteomics, is the first to show that general protein synthesis slows down and to identify the ribosome’s role in ageing.
One group of mice was provided with 35 per cent fewer calories than the other, but still got all the nutrients key for a healthy life. The study showed an almost linear increase in lifespan.
“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 are key to building the proteins that make a cell function. So it’s impractical to destroy ribosomes that start to malfunction.
Instead, individual parts of the ribosome can be regularly repaired, ensuring high quality proteins are produced for longer than they would be otherwise, keeping the cells functioning properly for longer.
Price cautioned, however, that people shouldn’t expect calorie counting to lead to eternal youth. After all, eating less hasn’t been tested as an anti-ageing strategy in humans.
But he said the study highlights why we should take 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.”