Can changing eating time aid healthy ageing? Study sheds light

A study published in the journal Science suggested that adjusting eating times to manipulate the circadian rhythm, which governs our sleep-wake cycles, may protect muscle function among older individuals.

Our bodies operate on an internal clock called the circadian rhythm, which orchestrates our sleep-wake cycles. This rhythm is finely tuned by exposure to light and darkness, and disruptions to it, such as those experienced by shift workers, can have significant health ramifications.

As we age, changes in our sleep-wake cycle often accompany the loss of muscle mass. Research suggests a close interplay between these two phenomena. While most individuals experience a shift towards earlier sleep hours with age, some, particularly those with neurodegenerative conditions, may encounter severe irregularities in their sleep patterns.

Clock genes play a crucial role in regulating circadian rhythms. As animals age, studies have observed a decline in the expression of these genes, potentially leading to disruptions in their circadian rhythms. While human research in this area is still limited, similar mechanisms could be at play.

In their study, researchers utilized a mouse model with a Bmal1 knockout, preventing the expression of this critical clock gene which regulates circadian rhythms, particularly in the brain. However, they were able to reintroduce Bmal1 in various tissues, including skeletal muscle.

They observed abnormal patterns in activity, oxygen consumption, energy expenditure, and glucose/lipid metabolism in the knockout mice compared to the wild-type, indicating circadian rhythm disruption due to the absence of this clock gene.

However, when the researchers restored the expression of the gene in both muscle and brain tissues in certain mice, they managed to preserve muscle mass and strength, highlighting the significance of Bmal1 in maintaining muscle health.

The findings indicated that by implementing time-restricted feeding, rhythmic gene expression in the muscles can be restored, which prevented the deterioration of muscle function.

“These findings help to explain some of the physiological changes that might be occurring as we age, and how time-restricted eating might help correct this, but this needs to be confirmed in human trials before we can make too many conclusions on the impacts of the circadian clock on aging in humans,” said Amy Hutchison, postdoctoral researcher at The University of Adelaide, Australia.

Reference: Arun Kumar et al.,Brain-muscle communication prevents muscle aging by maintaining daily physiology.Science384,563-572(2024).DOI:10.1126/science.adj8533