Washington DC (US) [US], January 19 (HBTV): Scientists have found that higher muscle mass and lower levels of hidden abdominal fat are associated with a younger biological brain age, suggesting that body composition plays a key role in brain health.
The study showed that deep visceral fat, stored around internal organs, appeared to accelerate brain ageing, while muscle mass had a protective effect. Researchers reported that people with more muscle and a lower visceral fat-to-muscle ratio tended to have brains that appeared biologically younger.
The findings will be presented next week at the annual meeting of the Radiological Society of North America. Visceral fat refers to fat stored deep in the abdomen, unlike subcutaneous fat, which lies just beneath the skin.
‘Healthier bodies with more muscle mass and less hidden belly fat are more likely to have healthier, youthful brains. Better brain health, in turn, lowers the risk for future brain diseases, such as Alzheimer’s,’ said senior study author Cyrus Raji, MD, PhD, associate professor of radiology and neurology at the Mallinckrodt Institute of Radiology, Washington University School of Medicine in St. Louis, Missouri.
Brain age is an estimate of how old the brain appears biologically, based on its structure observed through MRI scans. Body MRI can also measure muscle mass, which is an important indicator of overall physical health and frailty risk. Researchers noted that estimates of brain age from structural scans may also offer insights into risk factors for Alzheimer’s disease, including muscle loss.
‘While it is commonly known that chronological ageing translates to loss of muscle mass and increased hidden belly fat, this work shows that these health measures relate to brain ageing itself,’ Raji said. ‘It shows muscle and fat mass quantified in the body are key reflectors of brain health, as tracked with brain ageing.’
The study analysed data from 1,164 healthy adults, 52 per cent of whom were women, across four research sites. Participants had an average age of 55.17 years. Whole-body MRI scans were conducted using T1-weighted sequences, which clearly distinguish fat, fluid, muscle and brain tissue. An artificial intelligence algorithm was then used to measure total normalised muscle volume, visceral fat, subcutaneous fat and to predict brain age.
The analysis found that individuals with a higher visceral fat-to-muscle ratio had a higher predicted brain age, indicating accelerated brain ageing. Subcutaneous fat showed no meaningful link to brain age.
‘Participants with more muscle tended to have younger-looking brains, while those with more hidden belly fat relative to their muscle had older-looking brains,’ Raji said. ‘The fat just under the skin was not related to brain ageing. In short, more muscle and a lower visceral fat-to-muscle ratio were linked to a younger brain.’
Raji said the findings highlight practical and achievable health goals, such as building muscle and reducing visceral fat. He added that whole-body MRI and AI-based brain age estimates could serve as benchmarks for programmes aimed at improving body composition while protecting brain health.
The results may also have implications for the use of glucagon-like peptide-1 weight loss drugs, such as Ozempic, which are effective at reducing fat but may also lead to muscle loss. Raji suggested that future treatments could be designed to reduce visceral fat more selectively while preserving muscle mass.
‘Losing fat, especially visceral fat, while preserving muscle volume would have the best benefit on brain ageing and brain health based on insights from our work,’ he said. ‘Our study can inform future treatments by promoting research that quantifies MRI measures of body fat, muscle and brain age to determine optimal dosing strategies for the best body and brain health outcomes.’
(ANI)