According to a study, pumping iron at the gym could help protect against dementia.
US researchers found that people who had more muscle mass over their lifetime were 12 percent less likely to develop the deadly disease in old age.
They looked at data from more than a million people to find out how their body composition affected their brains in later years.
dr Iyas Daghlas of the University of California, San Francisco said the study “suggests a cause-and-effect relationship between muscle mass and the risk of Alzheimer’s disease.”
Around 900,000 Britons have dementia and experts predict the number will rise to 1.6 million by 2040.
Alzheimer’s is the most common form of the disease and is thought to be caused by the buildup of proteins in the brain, including tau and amyloid.
Obesity has been linked to an increased risk of Alzheimer’s disease in numerous studies.
A lower percentage of muscle mass is also associated with a higher risk of disease, although it is not clear whether this occurs before or after diagnosis.
The latest study, published in the BMJ, used a genetic prediction technique called Mendelian randomization to obtain data on the link between muscle mass and Alzheimer’s.
The researchers estimated muscle and fat tissue in the arms and legs, taking into account age, gender and genetic ancestry.
On average, higher muscle mass was associated with a small but statistically significant decrease in Alzheimer’s risk.
Researchers found that lean mass was also associated with better performance on cognitive tasks.
Body fat wasn’t linked to risk of Alzheimer’s disease, but it was linked to poorer performance on cognitive tasks.
The results of dr. Daghlas “also disprove a major impact of fat mass on Alzheimer’s risk.”
He said they “emphasize the importance of distinguishing between muscle mass and fat mass when examining the impact of obesity measures on health outcomes.”
But he added, “Our findings need to be replicated with independent complementary lines of evidence before entering public health or clinical practice.”
“Further work is needed to determine the cut-off age at which changes in muscle mass may no longer reduce risk.”