Forget Supplements? This One Vitamin Might Save Your Aging Brain, Scientists Say

A recent investigation involving more than 2,000 elderly individuals in Japan revealed that decreased vitamin C concentrations in the bloodstream are associated with diminished gray matter volume and weakened connectivity within a crucial brain network related to memory and attention. This research, led by Haruka Nagaya of Hirosaki University and published in PLOS One, underscores a potential link between nutritional status and brain health in aging populations.

Vitamin C, widely recognized for its role in immune support, also functions as a potent antioxidant that protects nerve cells from oxidative damage. Prior studies have connected diets high in vitamin C with a reduced risk of cognitive decline in older adults, but few have directly measured how circulating vitamin C levels correspond with brain structure and inter-regional neural communication.

To explore this relationship, the researchers analyzed magnetic resonance imaging (MRI) data alongside blood plasma samples from 2,044 Japanese adults aged 64 and above. They quantified gray and white matter volumes across the brain, adjusting for variations in overall brain size. The study also focused on the default mode network (DMN), a set of interconnected brain regions active during internal thought processes and involved in memory, self-reflection, and attention.

Vitamin C Levels and Brain Structural Connectivity

Controlling for variables such as age, physical activity, and education, the study found that participants with lower plasma vitamin C exhibited reduced gray matter volume and decreased connectivity within the DMN. These findings suggest that maintaining sufficient vitamin C levels might support cognitive function and mitigate age-related decline, though the study does not establish causality. Further research is required to elucidate the biological mechanisms underlying these associations.

The authors recommend future investigations to monitor vitamin C levels longitudinally, incorporate a wider array of lifestyle and dietary factors, and include participants from diverse ethnic and socioeconomic groups.

Implications for Cognitive Function and Brain Networks

Co-author Tomohiro Shintaku stated, “Our study demonstrates that higher plasma vitamin C levels are associated with better preserved structural connectivity of the default mode network (DMN), a key brain network involved in cognitive function. This finding generates the exciting hypothesis that a diet rich in vitamin C might play a supportive role in maintaining brain health and mitigating age-related cognitive decline in older adults.”

He added, “What I found most fascinating about this research is that we were able to detect these subtle but significant associations between a single nutritional factor and large-scale brain networks by utilizing a robust, community-based cohort of over 2,000 older adults. It truly highlights the potential impact of our everyday dietary habits on our brain structures.”

The study, titled “Plasma vitamin C levels are associated with brain structural networks on MRI: A large cohort study,” was authored by Haruka Nagaya and colleagues and published on June 10, 2026, in PLOS ONE (DOI: 10.1371/journal.pone.0348504).

Funding for this research included support from KAGOME CO., LTD., which provided salaries for authors D.K. and Y.U. but did not influence the study’s design, data collection, analysis, publication decisions, or manuscript preparation. Additional backing was provided by the Japan Agency for Medical Research and Development (AMED) under Grant Numbers JP16dk0207025 and JP21dk0207053.