The observational study included 2,044 participants living in Hirosaki City, Japan, who were originally included in a study exploring dementia and heart disease risk. The average age was 69, and 61% of them were female.

MRI scans are used to calculate the volume of gray matter and white matter in their brains.

Even after accounting for external factors like age, smoking habits, diabetes, and other lifestyle behaviors, they found that those with lower vitamin C levels appeared to have lower brain tissue volumes and weaker structural network patterns.

This network is often affected by conditions such as Alzheimer’s disease and depression, according to the researchers.

The vitamin C measurement was more accurate than studies that relied on dietary estimates, the researchers noted.

“What I found most fascinating is that we could detect such clear associations between a single nutritional factor (vitamin C) and large-scale brain networks in a robust cohort of over 2,000 older adults,” Shintaku said. “It highlights how significantly our everyday dietary habits might impact brain structure.”

The study underscores the importance of obtaining vitamin C from the daily diet, as humans cannot synthesize it on their own, the researchers noted.

“Our findings suggest that maintaining optimal vitamin C levels through a healthy diet — rich in citrus fruits, berries, tomatoes, and green leafy vegetables — could be a simple yet powerful way to support brain health as we age,” Shintaku said.

The study did have some limitations, the researchers noted. 

“Because our study is observational and cross-sectional, we can only show an association, not a cause-and-effect relationship,” Shintaku told Fox News Digital. “Other limitations include relying on a single blood measurement per participant.”

Other external factors, such as dietary intake, body mass index, and socioeconomic variables, could have played a role in the outcomes.

Also, the link was relatively modest compared to established risk factors like high blood pressure and blood sugar, the researchers noted.

Findings from other, larger studies, including UK Biobank research with more than 9,000 people, suggest that vitamin C is just one of several factors that may influence brain health.

Because the participants were almost all older Japanese adults, the findings may not be generalized to other populations.

“It is best viewed as a signal that vitamin C status may be one piece of a much larger brain-health picture.”