Study Finds Link Between Lower Vitamin C Levels and Smaller Gray-Matter Volume in Older Adults

A study of 2,044 Japanese adults over age 64 found that participants with lower plasma vitamin C levels had reduced gray matter volume and weaker connectivity in the default mode network after adjustments for age, education and physical activity, Newsweek reported.

The research, led by Haruka Nagaya of Hirosaki University, combined MRI scans with blood plasma measurements to assess gray matter, white matter and network connectivity. Gray matter houses neuron cell bodies that support memory, attention, language and decision-making.

The default mode network ranks among the brain's primary communication systems and ranks among the earliest disrupted in Alzheimer's disease. Dr. Jessica McCarthy, a New Jersey-based neuropsychologist specializing in dementia assessment, said the findings shift focus from isolated brain regions to network-level changes.

"We have historically thought about Alzheimer's in the context of brain localization—meaning that change occurs in the brain because specific regions of the brain are impacted, like the hippocampus, which is responsible for converting short-term memory into long-term storage, and the frontal lobe, which is responsible for the executive functions," she said.

" McCarthy added that neurodegenerative conditions increasingly appear as disorders of brain networks rather than single structures. Faster-than-expected gray matter loss has already been tied to mild cognitive impairment and various dementias.

The study remains observational and cannot prove that vitamin C directly preserves brain tissue, Newsweek reported. McCarthy noted the results still point to possible lifestyle influences. "While this study cannot tell us whether vitamin C preserves gray matter, it raises an intriguing possibility that lifestyle choices such as consumption of foods rich in vitamin C may help," she said.