Anti-ageing breakthrough: Scientists pinpoint hormone that extends mice lifespan

Mice fed a low-protein diet live longer – and the effects are visible even in old mice.

Now a study has pinpointed the hormone involved, and may help to shed light on why such diets could have anti-ageing effects.

The scientists hope that the finding might be used to unlock treatments that could be effective in human beings.

Researchers from Pennington Biomedical Research Center at Louisiana State University found that reducing the amount of protein in the diet of mice produced an array of favourable health outcomes, including an extension of lifespan.

The effects depend on a liver-derived metabolic hormone called Fibroblast Growth Factor 21 (FGF21).

Christopher Morrison, professor and director of the Neurosignaling Lab at Pennington Biomedical Research Center, said: “Our data suggest that FGF21 talks to the brain, and that without this signal the mouse doesn’t ‘know’ that it is eating a low-protein diet.

“As a result, the mouse fails to adaptively change its metabolism or feeding behaviour.”

The research comes at a time when Silicon Valley’s billionaires are investing in a range of well-funded start-ups aiming to reverse ageing.

Amazon’s Jeff Bezos is reported to have invested in Altos Labs, which aims to "restore cell health" and "reverse disease".

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PayPal co-founder Peter Thiel has invested in the Methuselah Foundation, which has the goal of making "90 the new 50".

Several previous studies have shown that reducing the amount you eat improves health and extends lifespan – so diets that are low in protein, but not so low that they produce malnutrition, can improve health.

The new study shows that low-protein diets produce beneficial metabolic effects in aged mice, improving metabolic health, reducing frailty, and extending lifespan.

These beneficial effects were also apparent when protein intake was reduced in middle-aged mice, even protecting against obesity.

But these beneficial effects were lost in mice that lacked FGF21, suggesting that its action in the brain is critical for the increase in health and lifespan.

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Dr Cristal Hill said: “We previously showed that FGF21 acts in the brain to improve metabolic health in young mice fed a low-protein diet. These new data extend this work by demonstrating that FGF21 also improves metabolic health and extends lifespan.

“Collectively, these data provide clear evidence that FGF21 is the first known hormone that coordinates feeding behaviour and metabolic health to improve lifespan during protein restriction.”

It’s unclear exactly how these observations will translate to ageing humans, the researchers said, but the hope is that the work will uncover novel molecular and neural pathways that can be used to improve health in people.

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