Hormone released in exercise may help prevent Alzheimer's
Scientists have given us another reason to join the gym this January and exercise more - but it could make a lasting difference.
A hormone released during exercise may protect the brain against Alzheimer's disease, new research suggests.
Irisin is a messenger protein generated by muscle tissue that is carried around the body in the bloodstream.
The new evidence indicates that it may be behind the known positive effects on mental performance of taking exercise.
US and Brazilian scientists found lower levels of the hormone in the brains of Alzheimer's patients compared with healthy individuals.
The same was true in the research for the precursor protein from which irisin is derived, FNDC5.
In tests on genetically engineered mice, the scientists induced learning and memory deficits by cutting out irisin.
They were able to reverse these effects by restoring the hormone.
When irisin signalling was blocked in mice with a rodent version of Alzheimer's, the brain benefits of physical exercise were lost.
The research, led by Dr Fernana de Felice, from the Federal University of Rio de Janeiro in Brazil, is reported in the journal 'Nature Medicine'.
Bolstering irisin, either with drugs or through exercise, could provide a "novel strategy" for preventing cognitive decline in patients with Alzheimer's disease, said the scientists.
Further research was needed to understand exactly how irisin enters the brain and interacts with it, the team added.
British experts pointed out that the research, though promising, was at a very early stage.
Dr James Pickett, head of research at the UK's Alzheimer's Society charity, said: "Although this study was only in mice, it adds to mounting evidence of the relationship between lifestyle factors, like physical fitness, and dementia.
"This is a promising avenue for more research and potentially new therapies in future."