A new study of 2,044 older Japanese adults reveals that low levels of vitamin C in the blood are associated with reduced gray matter volume and weaker connectivity in the default mode network (DMN)—a set of brain regions critical for memory, self-reflection, and attention.
The Research
Published June 10, 2026 in PLOS One, the study by Haruka Nagaya of Hirosaki University and colleagues used high-resolution MRI scans and direct blood plasma measurements—avoiding unreliable food diaries. The participants, all over age 64, were from a large community-based cohort in Japan. After adjusting for age, physical activity, education, and other confounders, the team found that those with lower vitamin C levels had significantly lower gray matter volume and reduced functional connectivity within the DMN. The association held even when accounting for total brain size differences.
Co-author Tomohiro Shintaku emphasizes that while the study shows a strong statistical link, it does not prove causality. He hypothesizes that vitamin C, a potent antioxidant, may protect the brain from cumulative oxidative stress that damages neural wiring over time.
Why It Matters
Your brain's gray matter houses neuronal cell bodies and processing hubs, while the DMN supports higher-order cognitive tasks like planning and autobiographical memory. Lower gray matter and DMN connectivity are hallmarks of age-related cognitive decline. This study suggests that maintaining adequate vitamin C levels might be a modifiable factor for brain health as you age.
What You Can Do
While more research is needed, ensuring sufficient vitamin C intake through diet (citrus fruits, bell peppers, strawberries, broccoli) or supplements (after consulting a healthcare provider) is a low-cost step that may support cognitive resilience.
Source: Neuroscience News
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