According to a new study in rhesus macaques, a calorie-restricted diet may slow the natural aging that occurs in the brain as we age, and these findings may have implications for brain diseases such as Alzheimer’s disease.
Researchers led by a team from Boston University analyzed the brains of 24 rhesus macaques that had been on either restricted or standard calorie diets for more than 20 years.
After these lifelong dietary differences, the researchers found signs of improved neural communication and greater cellular protection in the brain tissue of animals that consumed 30% fewer calories.
These findings add to what was previously known about low-calorie diets: when the body gets less fuel, it enters a more efficient metabolic mode. This pattern, according to the study, appears to have contributed to reducing some of the cellular wear and tear typically associated with aging.
“While calorie restriction is a proven intervention that can slow biological aging and reduce age-related metabolic changes in short-lived experimental models, this study provides rare long-term evidence that calorie restriction may also protect against brain aging in more complex species,” said the study’s first author, Boston University neuroscientist Anna Vitantonio.
The role of myelin in protecting the brain
The research team focused specifically on myelin, which is the fatty covering that surrounds nerve fibers in the brain, and contributes to accelerating the transmission of nerve signals and protecting them. As we age, myelin deteriorates, which can lead to neuroinflammation.
In monkeys on a low-calorie diet, there were strong indications that the myelin sheath was in better condition. Genes associated with myelin were more active, and the metabolic pathways responsible for its production and maintenance showed better performance.
The researchers also found that the cells responsible for producing and maintaining myelin were working more efficiently, which reduced some of the signs of aging that appeared in the monkeys that ate a standard diet.
“This is important, because these cellular changes may have implications for cognition and learning,” said neuroscientist Tara Moore of Boston University.
What does this have to do with neurological diseases?
As is the case with the rest of the body’s organs, the efficiency of brain mechanisms declines over time. In some cases, the mechanisms that maintain brain health may get out of control, leading to chronic neuroinflammation.
For this reason, the probability of developing diseases such as Alzheimer’s and Parkinson’s increases with age, as brain cells become more fragile, and their hyperactivity may lead to unintended damage, especially with the deterioration of the protective covering around nerve cells.
In recent years, scientists have reexamined the link between Alzheimer’s disease and demyelination, adding experimental evidence of its degeneration to neuroimaging data in people with rapid cognitive decline. This study adds additional evidence suggesting a possible protective intervention through diet.
Do the results apply to humans?
Although the study was conducted on a relatively limited number of monkeys, their brains are very similar to those of humans, giving reason to assume that the results may be applicable to humans, which future studies could explore.
“Dietary habits may affect brain health, and reducing calories may help slow some aspects of brain aging if done over the long term,” Moore said.
However, other studies indicate that brain aging does not depend on diet alone, as other factors play an important role, such as sleep quality, level of mental activity, and language learning.
