Low carb diet may prevent, reverse age-related effects in brain: Study

Minimising the consumption of carbohydrates may prevent and reverse age-related effects within the brain, according to a study.

The research, published in the journal PNAS, reveals that neurobiological changes associated with ageing can be seen at a much younger age than would be expected, in the late 40s.

To better understand how diet influences brain ageing, the researchers from Stony Brook University in the US focused on the presymptomatic period during which prevention may be most effective.

They showed, using large-scale life span neuroimaging datasets, that functional communication between brain regions destabilises with age, typically in the late 40's.

That destabilisation correlates with poorer cognition and accelerates with insulin resistance, the researchers said.

Targeted experiments then showed this biomarker for brain ageing to be reliably modulated with consumption of different fuel sources.

As glucose decreases, and ketones increase, the stability of brain networks, the researchers said.

"The bad news is that we see the first signs of brain ageing much earlier than was previously thought," said lead author Lilianne R. Mujica-Parodi, a professor at Stony Brook University.

"However, the good news is that we may be able to prevent or reverse these effects with diet, mitigating the impact of encroaching hypometabolism by exchanging glucose for ketones as fuel for neurons," Mujica-Parodi said.

To conduct their experiments, brain network stability was established as a biomarker for ageing by using two large-scale brain neuroimaging (fMRI) datasets totaling nearly 1,000 individuals, aged 18 to 88.

Destabilisation of brain networks was associated with impaired cognition and was accelerated with Type 2 diabetes, an illness that blocks neurons' ability to effectively metabolise glucose, according to the researchers.

To identify the mechanism as being specific to energy availability, they then held age constant and scanned an additional 42 adults under the age of 50 years with fMRI.

This allowed them to observe directly the impact of glucose and ketones on each individual's brain.