Humans cannot synthesize their own vitamin C, making dietary intake the sole source of this critical nutrient. It concentrates in brain tissue, with cerebrospinal fluid levels double that of blood plasma.
Researchers at Hirosaki University in Japan analyzed blood samples and brain scans from 2,044 volunteers, with a median age of 69, to investigate the relationship between vitamin C and brain structure. The study focused on the default mode network (DMN), a critical brain circuit active during rest that is associated with memory and emotion.
The findings established a clear, direct relationship. Higher plasma vitamin C levels correlated with a greater volume of gray matter, the tissue responsible for memory, movement, and emotion. Additionally, participants with more vitamin C demonstrated stronger connectivity within their DMN.
This large-scale network connects crucial regions, including the ventromedial prefrontal cortex and the posterior cingulate cortex. A weakening of DMN connections has been previously linked to Alzheimer’s, Parkinson’s, and depression. The study suggests adequate vitamin C may help maintain the integrity of this network, potentially mitigating age-related cognitive decline.
Radiologist Tomohiro Shintaku noted the research highlights the potential impact of daily dietary habits on brain structures. While the cross-sectional study does not establish direct causation, it is the first to demonstrate this specific association between plasma vitamin C levels and DMN connectivity, according to the research team.