Muscle Health May Offer Greater Brain Health Benefits Than Ozempic

Improving muscle health could deliver larger benefits for brain health than the current focus on weight-loss anti-obesity medicines such as Ozempic, according to researchers behind a recent study.

A retrospective study by scientists at Sichuan University in China found that grip strength and the pattern of subcutaneous fat distribution were more effective at forecasting neurodegenerative diseases and biological markers of brain ageing than broader measures of muscle mass and total body fat.

"This study highlights the potential to lessen people's risk of developing these diseases by improving their body composition," explains Sichuan University epidemiologist Huan Song.

Muscle strength and neurodegenerative disease risk

The researchers, led by Sichuan University physician Shishi Xu, examined nine years of data from 412,691 UK Biobank participants. Their average age was 56 when the study began, and 8,224 subsequently developed dementia, including Alzheimer's and Parkinson's diseases.

People who retained comparatively strong grip strength throughout the study had a 26 percent lower chance of developing a neurodegenerative condition such as dementia.

"Muscle quality, compared with muscle quantity, might play a more important role in the development of neurodegenerative diseases," the researchers write in their paper.

Arm fat, belly fat and brain ageing

The analysis further showed that participants with a greater amount of arm fat relative to leg fat were 18 percent more likely to be diagnosed with a neurodegenerative condition.

This does not, of course, show that arm fat causes neurodegenerative conditions. In addition, most participants were of Anglo-Saxon descent, meaning the results may not apply to other populations.

Nevertheless, the way fat is distributed across the body may at least indicate health issues that can worsen brain ageing. For instance, many participants who later developed a neurodegenerative condition had a history of heart disease and stroke, both of which are directly associated with excess fat.

Subcutaneous fat may signal fatty deposits in visceral organs, including the muscles, which can raise inflammation and disrupt their function. This can then damage the inner lining of blood vessels, directly contributing to heart disease. Xu and colleagues suspect that this same lining dysfunction could also have a role in neurodegeneration.

Genes for fat-transporting proteins have likewise been connected with Alzheimer's disease, as have fatty diets in animal research and western diets in humans, which are well known for promoting unhealthy weight gain.

However, "the underlying mechanisms linking body composition and neurodegeneration have not been fully investigated," Xu and team explain.

Moreover, serious illnesses including stroke and heart disease can themselves make it much more difficult for patients to maintain muscle tone and manage changes in their weight.

"This underscores the importance of managing these cardiovascular diseases right away to help prevent or delay the development of Alzheimer's, Parkinson's, or other degenerative diseases," says Song.

Body fat distribution and prevention

Belly fat was also linked with a greater risk of neurodegeneration. Among men with high trunk fat levels, the disease rate was 3.38 cases per 1,000 person years, versus 1.83 cases in men with low levels of belly fat. For women with high abdominal fat levels, the neurodegenerative disease rate was 2.55 per 1,000 person years, compared with 1.39 among women with low amounts of belly fat.

"Targeted interventions to reduce trunk and arm fat while promoting healthy muscle development may be more effective for protection against these diseases than general weight control," suggests Song.

"These neurodegenerative diseases like Alzheimer's and Parkinson's affect over 60 million people worldwide, and that number is expected to grow as the population ages, so it's crucial that we identify ways to modify risk factors to develop some preventive tools."

This story was published in Neurology.