Eating Less Can Protect Your Brain For Decades

A 30% caloric restriction over more than 20 years in rhesus monkeys promoted specific genetic changes in oligodendrocytes and microglia, reducing inflammation and strengthening mechanisms linked to myelin maintenance. These changes suggest that caloric restriction may partially protect the brain's white matter against the effects of aging, helping to preserve neural communication and possibly cognitive function.

Brain aging doesn't just affect neurons. One of the most consistent changes observed in both humans and monkeys is the loss of white matter, the brain's "wiring," formed by myelin-coated nerve fibers.

This loss is especially evident in the frontal lobe, a region linked to planning, working memory, and decision-making. Over time, myelin suffers structural damage, which impairs the speed and efficiency of communication between neurons and is associated with cognitive decline.

In addition to myelin deterioration, aging also alters the behavior of glial cells, which support and protect neurons. Among them, two are especially important: oligodendrocytes, responsible for producing myelin, and microglia, which act as the brain's immune system.

With age, oligodendrocytes become more vulnerable to oxidative stress and metabolic failures, while microglia tend to adopt a more inflammatory profile and become less efficient at removing cellular debris. This set of changes contributes to the progressive deterioration of white matter.

To better understand these processes, researchers use the rhesus monkey as an experimental model. The brain of this primate is more similar to that of humans than to that of rodents, especially in the development of white matter.

Furthermore, the cognitive aging of rhesus monkeys follows a pattern similar to that of humans, but without typical neurodegenerative diseases such as Alzheimer's, which allows for a more controlled study of "normal" aging.

Oligodendrocyte (white) next to neurons (yellow)

In this context, scientists investigated the effects of long-term caloric restriction, a 30% reduction in calorie intake over more than 20 years, in rhesus monkeys. Caloric restriction is already known to slow down some biological markers of aging, improve energy metabolism, and reduce oxidative damage. In the study, the animals were divided between a normal diet and a diet with 30% fewer calories, while maintaining all essential nutrients.

But how did the researchers assess what changed in the brain? They used a technique called single-core RNA sequencing. This method allows scientists to analyze which genes are active within each individual cell type. Instead of studying the tissue as a whole, scientists can observe the specific “molecular profile” of oligodendrocytes and microglia.

Microglia

To confirm the results, they also applied microscopic visualization techniques, such as in situ hybridization and immunohistochemistry, which allow for the direct localization of specific proteins and molecules in brain tissue.

The results showed that caloric restriction promoted modest but significant changes in the genetic activity of glial cells. In oligodendrocytes, there was an increase in the expression of genes linked to the production and maintenance of myelin.

Greater activation of metabolic pathways related to energy production and the synthesis of fatty acids, fundamental for building myelin, which is rich in lipids, was also observed. In some cases, these oligodendrocytes were closer to the axons, suggesting a possible improvement in functional interaction.

Microglia showed a less inflammatory profile in animals subjected to caloric restriction. Genes linked to amino acid and peptide metabolic pathways were more active, while inflammatory signals were reduced. Furthermore, a smaller amount of accumulated myelin debris was observed, indicating that the brain's "cleaning" system was functioning more efficiently.

These findings suggest that reducing caloric intake throughout life may partially reprogram the molecular functioning of glial cells, better preserving the integrity of white matter during aging. Although the changes do not completely reverse brain aging, they appear to attenuate inflammatory and metabolic processes that contribute to cognitive decline.

READ MORE:

Calorie Restriction Attenuates Transcriptional Aging Signatures in White Matter Oligodendrocytes and Immune Cells of the Monkey Brain

Ana T. Vitantonio, Christina Dimovasili, Yuchen Liu, Bingtian Ye, Jou-Hsuan Roxie Lee, Molly Hartigan, Benjamin Bouchard, Madelyn Ray, Bryce Conner, Kelli L. Vaughan, Julie A. Mattison, Tara L. Moore, Chao Zhang, and Douglas L. Rosene

Aging Cell. Volume25, Issue1 January 2026 e70298

DOI: 10.1111/acel.70298

Abstract:

During brain aging, terminally differentiated neuroglia exhibit metabolic dysfunction and increased oxidative damage, compromising their function. These cellular and molecular alterations impair their ability to maintain myelin sheath integrity, contributing to age-related white matter degradation. Calorie restriction (CR) is a well-established intervention that can slow biological aging and may reduce age-related metabolic alterations, thereby preserving the molecular function of aging glia. Here we present a single nucleus resolution, transcriptomics dataset evaluating the molecular profile of oligodendrocytes and microglia in the brain of aging rhesus monkeys following lifelong, 30% calorie restriction. Oligodendrocytes from CR subjects exhibited increased expression of myelin-related genes and showed enrichment in glycolytic and fatty acid biosynthetic pathways. In CR subjects, a subpopulation of oligodendrocytes upregulated cell adhesion gene, NLGN1 and were in closer proximity to axons. Microglia from CR subjects upregulated amino acid and peptide metabolism pathways and showed a reduced myelin debris signature. Our findings reveal cell-type specific transcriptional reprogramming in response to long term CR and highlight potential protective mechanisms against myelin pathology in the aging primate brain.