Low Vitamin C Linked to Reduced Brain Volume, Study Finds

While vitamin C is best known for immune support and antioxidant defense, it plays several underappreciated roles in the brain.

Illustration by The Epoch Times, Shutterstock

Vitamin C earned its reputation as an immune booster. But scientists are increasingly finding that one of its most important roles may be protecting the aging brain.

That possibility gained new support from a recent study of more than 2,000 older Japanese adults. Researchers found that participants with lower blood vitamin C levels had less gray matter and weaker communication within one of the earliest brain networks affected in Alzheimer’s disease.

Think of it this way: If your brain were a city, gray matter would be the buildings and neural networks—the highways connecting them, according to Dr. Thomas Holland, a clinician-researcher who studies cognitive aging and was not involved in the study.

“Individuals with higher vitamin C levels appeared to have both more preserved ‘buildings’ and healthier ‘roadways’ connecting critical regions of the brain,” Holland told The Epoch Times.

Changes in Key Brain Regions

The findings, published in PLOS One, followed adults with an average age of 70. Participants underwent MRI scans to assess brain volume and connectivity, and researchers measured blood vitamin C levels after an overnight fast.

Lower blood vitamin C levels were associated with reduced gray matter volume and weakened connectivity within the brain’s default mode network (DMN), a network of connected brain regions involved in memory, self-reflection, and future planning.

Gray matter contains many of the brain’s nerve cells, and lower gray matter volume is considered a marker of brain tissue loss and shrinkage.

The association remained even after adjusting for age, sex, cognitive status, education, and lifestyle factors such as smoking, drinking, and physical activity.

“Structural loss and decreased connectivity within the DMN are known early clinical manifestations of cognitive impairment, such as in Alzheimer’s disease and mild cognitive impairment,” Dr. Tomohiro Shintaku, assistant professor at Hirosaki University and corresponding author of the study, told The Epoch Times.

The effect of vitamin C on brain structure was comparable in magnitude to established lifestyle and vascular risk factors, suggesting even modest differences could matter at the population level, he said.

Why Vitamin C May Matter for the Brain

While vitamin C is best known for immune support and antioxidant defense, it plays several underappreciated roles in the brain. It helps neutralize free radicals that accumulate with age, potentially protecting the structural integrity of brain tissue over time. It also supports the synthesis of neurotransmitters, the chemical messengers brain cells use to communicate.

Humans cannot produce vitamin C on their own and must get it entirely through diet. Rich sources include citrus fruits, berries, and leafy green vegetables.

The recommended dietary allowance is 75 mg per day for most adult women and 90 mg for most adult men. While some researchers have proposed that higher intakes may provide additional benefits by fully saturating body tissues, the optimal intake for long-term brain health has not yet been established.

Previous Research

The new findings add to a growing body of evidence linking healthy vitamin C status with better cognitive health.

A 2002 Netherlands study followed 5,395 people for six years and found that high intake of vitamin C and E was tied to an 18 percent lower risk of Alzheimer’s disease.

Other studies have found that even vitamin C levels that are too low to cause classic deficiency symptoms have been associated with poorer memory and slower information processing in older adults.

A 2022 review of 12 studies likewise found that people with Alzheimer’s disease consistently had significantly lower blood vitamin C levels than cognitively healthy adults, suggesting the nutrient may play a role in disease progression.

Older adults may be at greater risk of low vitamin C levels due to reduced appetite, less varied diets, and changes in digestion and absorption that occur with age, Jen Scheinman, a New York-based registered dietitian nutritionist, told The Epoch Times. Chronic health conditions, inflammation, and some medications can further increase the body’s demand for vitamin C.

Vitamin C Is Just a Piece of the Puzzle

The researchers caution that the study does not prove vitamin C directly protects the brain. One reason is that people with higher vitamin C levels often have healthier lifestyles overall.

Vitamin C should be considered one part of an overall dietary pattern, such as the Mediterranean or MIND (Mediterranean-DASH Intervention for Neurodegenerative Delay) diet, Holland said.

“No single food or vitamin can prevent dementia,” Holland said. “But consistently eating a nutrient-rich diet—including plenty of vitamin C-rich fruits and vegetables—may help preserve cognitive function over the long term.”