Fat arms heightens risk of brain disease by nearly 20pc

Excess weight in one area may ‘poison’ muscles and eventually trigger Alzheimer’s and Parkinson’s, study finds

Having fat arms increases the risk of developing brain diseases such as Alzheimer’s or Parkinson’s disease by nearly one fifth, scientists have discovered.
A large study, which looked at the medical records of more than 400,000 Britons, found those with disproportionately high levels of fat stored in the arms were more likely to develop neurodegenerative diseases.
Researchers believe too much fat in one place may infiltrate and “poison” the muscles, leading to immune problems and inflammation that could trigger disease.
Chinese experts said the placement of body fat was more important than overall weight and too much focus on weight loss may be harming attempts to improve health.
Dr Shishi Xu, of the Department of Endocrinology and Metabolism at Sichuan University and first author of the study, said: “In recent years, due to the widespread use and even abuse of weight-loss drugs (such as semaglutide), people have become overly concerned with overall weight and often overlook the key role of different body components.
“Our findings highlight that targeted interventions to modulate body composition may be more effective for neurodegeneration protection than general weight control.”
At the beginning of the research, measurements were taken for body composition, such as waist and hip measurements, grip strength, bone density and fat and lean mass.
During the nine-year follow-up study, 8,224 people developed conditions such as Alzheimer’s disease, other forms of dementia, and Parkinson’s disease.
After adjusting for factors that could affect the rate, such as high blood pressure, smoking and drinking, researchers found that people with “arm dominant fat distribution” were 18 per cent more likely to develop brain diseases compared to those with low levels of arm fat.
Those with high levels of belly fat were also 13 per cent more likely to develop these diseases than people with low levels of belly fat.
However, people with high muscle strength seemed to be protected from the brain diseases, with a 26 per cent reduced chance of being diagnosed during the nine-year follow-up.
Dr Huan Song, one of the authors, of Sichuan University in Chengdu, China, said: “This study highlights the potential to lessen people’s risk of developing these diseases by improving their body composition.
“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.
“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.”
The researchers believe that the link between body fat and neurodegenerative disease can be partly explained by cardiovascular disease.
Overweight and obese people are more likely to suffer from heart disease and stroke, which also raises the chance of diseases such as dementia and Parkinson’s.
A healthy heart is crucial for supplying brain cells with energy and oxygen and excess weight can lead to fatty material building up in the blood vessels.
Dr Song added: “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.”
Rather than using body mass index for the study, the researchers looked at the ratio of fat distribution across the body, which they say is more important than focussing simply on weight.
People were considered as having “fat arms” if the proportion of arm fat mass was higher relative to the general whole-body mass fat.
The team believe that the higher risk may be caused by fat infiltrating muscles leading to dysfunction of tissues, impairing insulin signalling and damaging the immune system.
This infiltration can lead to the dysfunction of adipose and muscle tissues, impair insulin signalling, and release pro-inflammatory cytokines.
Dr Xu added: “A key point we want to share is that the quality or distribution of your muscle and fat, rather than the absolute weight, may be more important for your health.
“These findings underscore that the risk of neurodegenerative diseases is significantly influenced by the distribution and quality of body fat and muscle.
“Fat accumulation in the abdomen and arms appears to have a poisonous and inflammatory effect on other organs, including the cardiovascular system and neuro health, leading to a higher risk of neurodegenerative diseases.”
The research was published in the journal Neurology.