TOKYO—Higher blood levels of vitamin C were associated with healthier brain structure and stronger connectivity in regions linked to memory and attention in older adults, according to a large Japanese study, adding to evidence that nutrition may play a role in healthy brain aging while stopping short of proving a cause-and-effect relationship.
The findings, highlighted by PLOS on Wednesday following publication in the peer-reviewed journal PLOS One, were based on data from 2,044 adults aged 64 and older who participated in a community-based health study in Japan. Researchers compared participants' blood plasma vitamin C levels with magnetic resonance imaging (MRI) scans of their brains.
After accounting for factors including age, education, physical activity and several health conditions, the researchers found that participants with lower plasma vitamin C levels generally had smaller gray matter volume and weaker connectivity within the brain's default mode network, which is involved in memory, attention and other cognitive functions.
The research was led by Haruka Nagaya of Hirosaki University and colleagues. The authors said the results support the hypothesis that maintaining adequate vitamin C levels could contribute to preserving brain health during aging, but emphasized that the observational, cross-sectional design cannot establish that vitamin C directly caused the differences seen in brain structure or connectivity.
"Our study demonstrates that higher plasma vitamin C levels are associated with better preserved structural connectivity of the default mode network, a key brain network involved in cognitive function," study co-author Tomohiro Shintaku said in a statement released by PLOS. He added that the findings generate "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."
The researchers noted several limitations, including that vitamin C levels were measured only once and that the study population consisted primarily of older Japanese adults, which may limit the generalizability of the findings. They also said future studies should follow participants over time, include more diverse populations and examine additional dietary and lifestyle factors.
Previous research has linked higher dietary intake of vitamin C with a lower risk of cognitive impairment, but relatively few studies have examined whether blood vitamin C levels correspond with measurable changes in brain structure and neural networks. The new study provides further evidence of an association, though researchers stressed that additional research, including long-term and interventional studies, is needed before conclusions can be drawn about whether increasing vitamin C intake can help prevent cognitive decline.
