Vitamin C and Brain Ageing: Large MRI Study Links Higher Vitamin C Levels to Better Brain Structure

Vitamin C Levels Linked to Healthier Brain Structure in Older Adults

Vitamin C has long been recognised for its role in immune function and antioxidant defence. Now, a large new study suggests that it may also be important for maintaining brain health as we age.

Researchers from Japan analysed data from 2,044 adults with a median age of 69 years and investigated whether blood concentrations of vitamin C were associated with brain structure and neural network integrity. Using high-resolution MRI scans, the team examined brain volume and connectivity within the default mode network (DMN), a group of brain regions involved in memory, self-reflection, and cognitive processing.  

The researchers found that participants with lower plasma vitamin C levels tended to have reduced grey matter volume and weaker connectivity within the DMN. These associations remained significant even after adjusting for numerous factors, including age, sex, education, diabetes, hypertension, smoking history, alcohol consumption, physical activity, and cognitive status.

Importantly, vitamin C levels were positively associated with both grey matter and white matter volume. Higher vitamin C concentrations were also linked to stronger connectivity in several DMN-related structural networks. Brain regions showing the strongest associations included the posterior cingulate cortex, medial prefrontal cortex, and temporal regions, all of which are known to play important roles in memory and cognitive performance.

The default mode network has attracted considerable attention in neuroscience because disruptions in this network are commonly observed in ageing-related cognitive decline and neurodegenerative conditions such as Alzheimer's disease. The new findings suggest that vitamin C status may be linked to the preservation of these critical brain systems.  

Vitamin C is highly concentrated in the brain and serves several biological functions relevant to neural health. It acts as a powerful antioxidant, helps protect neurons from oxidative stress, participates in neurotransmitter synthesis, and supports normal cellular communication. These mechanisms provide plausible explanations for the observed relationship between vitamin C and brain structure.  

However, the researchers emphasise that the study was observational and cross-sectional. As a result, it cannot determine whether higher vitamin C levels directly improve brain health or whether individuals with healthier lifestyles simply tend to have both higher vitamin C levels and healthier brains. Longitudinal and intervention studies will be required to establish causality.  

The findings nevertheless add to growing evidence that nutrition may play an important role in maintaining cognitive resilience during ageing and highlight vitamin C as a potential factor worthy of further investigation.  

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Why This Matters for GeneFit Readers

Brain ageing is influenced by a complex interaction of genetics, lifestyle, nutrition, and environmental factors. While many people associate vitamin C primarily with immunity, this study suggests that adequate vitamin C status may also be linked to structural markers of brain health.

At GeneFit, we believe that precision health begins with understanding individual biological differences. Genetic variations can influence nutrient metabolism, antioxidant capacity, inflammation, and susceptibility to age-related cognitive decline. Integrating genetic insights with nutritional assessments may help identify individuals who could benefit from more personalised dietary strategies to support long-term brain health.

As research continues to uncover the relationship between nutrition and cognitive ageing, personalised approaches that combine genomics, lifestyle data, and evidence-based nutrition may become increasingly important for preserving brain function throughout life.

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Reference

Nagaya, H., Watanabe, K., Shintaku, T., Sasaki, M., Kudo, J., Kasai, S., Ishimoto, Y., Saito, K., Matsuhashi, S., Koshiishi, T., Kakehata, S., Mikami, T., Kokubu, D., Ushida, Y., Kuroda, Y., Miyazaki, T., Yamaguchi, M., Kudo, H., Hozawa, A., & Kakeda, S. (2026). Plasma vitamin C levels are associated with brain structural networks on MRI: A large cohort study. PLOS ONE, 21(6), e0348504. https://doi.org/10.1371/journal.pone.0348504

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