A low-carb diet may prevent and even reverse age-related changes of the brain

Neurobiological changes associated with ageing can be seen much earlier than would be expected, in the late 40’s, a new study shows. But now researchers may have found a way to prevent or reverse these effects.

Age-related brain changes may be prevented or reversed by minimizing the consumption of simple carbohydrates, the study led by Stony Brook University professor and lead author Lilianne R. Mujica-Parodi, suggests.

Communication between brain regions destabilizes with age

The team used large-scale life span neuroimaging datasets to show that functional communication between brain regions destabilizes with age and that destabilization correlates with poorer cognition and accelerates with insulin resistance.

To identify the mechanism as being specific to energy availability, the researchers then studied 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.

Effects of low carb diet compared to an unrestricted diet

The brain’s response to diets was tested in two ways. The first one was holistic, comparing brain network stability after participants had spent one week on an unrestricted and one week a low carb diet.

In an unrestricted diet, the primary fuel metabolized is glucose, whereas in a low-carb diet, the primary fuel metabolized is ketones. However, there might have been other differences between diets driving the observed effects.

Therefore, to isolate glucose vs. ketones as the crucial difference between the diets, an independent set of participants was scanned before and after drinking a small dose of glucose on one day, and ketones on the other, where the two fuels were individually weight-dosed and calorically matched.

The results replicated, showing that the differences between the diets could be attributed to the type of fuel they provide to the brain.

Even younger participants benefited

Even in younger adults, under age 50, dietary ketosis — whether achieved after one week of dietary change or 30 minutes after drinking ketones — increased overall brain activity and stabilized functional networks.

This is thought to be due to the fact that ketones provide greater energy to cells than glucose, even when the fuels are calorically matched. This benefit has previously been shown for the heart, but the current set of experiments provides the first evidence for equivalent effects in the brain.

“This effect matters because brain ageing, and especially dementia, are associated with “hypometabolism,” in which neurons gradually lose the ability to effectively use glucose as fuel. Therefore, if we can increase the amount of energy available to the brain by using a different fuel, the hope is that we can restore the brain to more youthful functioning,” explained Mujica-Parodi.

Effects of brain ageing emerged at 47

The study also revealed that the effects of brain ageing emerged at age 47, with most rapid degeneration occurring at age 60.

“The bad news is that we see the first signs of brain ageing much earlier than was previously thought. 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,” said Mujica-Parodi.

This article is based on materials provided by Stony Brook University. Content may have been edited for style and length. If you want to find out more, please contact the cited source.

Original journal article: Mujica-Parodi, L. R., Amgalan, A., Sultan, S. F., Antal, B., Sun, X., Skiena, S., … Clarke, K. (2020). Diet modulates brain network stability, a biomarker for brain aging, in young adults. Proceedings of the National Academy of Sciences, 201913042. https://doi.org/10.1073/pnas.1913042117