Could vitamin C, alongside its well-known benefits such as strengthening the immune system, improving iron absorption and protecting against free radicals, also contribute to brain health in older age? A new study from Japan found a link between low blood levels of vitamin C and changes in brain structure and the way different regions of the brain communicate with one another. The changes involved a brain network associated with memory, attention and thinking that is also sometimes affected by diseases such as Alzheimer’s.
The study found that people with lower blood levels of vitamin C tended to have smaller volumes of gray matter — the brain tissue that contains most nerve cells and plays a central role in information processing, memory and thinking. In addition, they showed weaker communication between brain regions within a network known as the default mode network (DMN).
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People with lower blood levels of vitamin C tended to have smaller volumes of gray matter
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This network is involved in processes such as memory, attention and information processing and previous studies have found that it may also be affected in conditions such as Alzheimer’s disease and depression.
However, the researchers emphasized that the findings do not prove that vitamin C protects the brain or prevents disease. They point only to an association between vitamin C levels and certain measures of brain health. Still, the study adds to a growing body of research suggesting that diet may play an important role in maintaining cognitive function in older age.
The study was published in the journal PLOS One and included 2,044 residents of the Japanese city of Hirosaki who originally took part in a broader study examining risk factors for dementia and heart disease. The participants’ average age was 69 and about 61% were women.
More accurate through blood tests, not questionnaires
Previous studies have already suggested a link between higher vitamin C intake and a lower risk of cognitive decline, but most relied on a less accurate method of measurement in which participants reported what they ate.
Diet may play an important role in maintaining cognitive function in older age
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In the current study, researchers used a more precise approach: They directly measured vitamin C levels through blood tests and then compared them with MRI brain scans. Even after accounting for factors that could influence the results, such as age, smoking, diabetes and lifestyle habits, the association remained clear — the lower the blood levels of vitamin C, the lower the amount of gray matter and the weaker the communication between brain regions.
“Our study shows that older adults with higher blood levels of vitamin C tend to better preserve gray matter volume and stronger connectivity within the default mode network — a key brain network involved in memory and cognitive function,” explained Dr. Tomohiro Shintaku, a radiologist at Hirosaki University and one of the study’s authors. “This is the first study to demonstrate an association between plasma vitamin C levels and the structural connectivity of this network.”
According to Shintaku, because humans cannot produce vitamin C on their own, it is important to obtain it regularly from food. “Maintaining normal vitamin C levels through a diet rich in citrus fruits, berries, tomatoes and leafy green vegetables may be a simple way to contribute to brain health as we age.”
Maintaining normal vitamin C levels may be a simple way to contribute to brain health as we age
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Keeping things in perspective: It is not a miracle cure
Alongside the encouraging findings, the researchers also highlighted the study’s limitations. Since participants were examined at only one point in time, it is impossible to determine whether low vitamin C levels caused the brain changes or whether the association stems from other factors. In addition, vitamin C levels were measured only once and variables such as body weight, socioeconomic status and other dietary habits may also have affected the results.
The researchers also noted that the association found was relatively modest and certainly weaker than the known impact of risk factors such as high blood pressure or diabetes on brain health. Other large studies, including one based on data from the UK Biobank that included more than 9,000 participants, also suggest that vitamin C is likely only one of many factors influencing brain health.
Dr. Dong Trinh, an internal medicine physician and founder of Healthy Brain Clinic, who commented on the study for Medical News Today, offered a cautious summary: “This study found an association between higher plasma vitamin C levels and MRI markers of brain health, including gray matter volume and connectivity in the default mode network, which is involved in several cognitive functions. That said, the study does not prove that vitamin C prevents cognitive decline or that taking supplements will improve brain health. It is best viewed as a signal that vitamin C status may be one piece of a much larger brain-health picture.”