The exciting connection between vitamin C and brain health

Higher levels of vitamin C in the blood and brain are associated with healthier brain structure and stronger brain networks in older adults. This is according to a large Japanese population study published in PLOS One. The researchers also found that people with lower levels of vitamin C in their blood tended to have less gray matter in the brain and weaker connections in brain networks associated with memory, attention, and other cognitive functions. So why does vitamin C have such an important role in brain health, and how can you get enough?

The brain functions as a command center that is essential for our mental and physical well-being throughout life. The outer layer, also known as gray matter, consists of billions of nerve cells that process information, thoughts, and cognitive functions. The underlying white matter consists of long nerve fibers that connect nerve cells with different areas of the brain, allowing various signals to travel rapidly throughout the central nervous system.
However, brain volume gradually decreases as part of the aging process, although this does not necessarily affect cognitive function. Progressive deterioration of nerve cells can, however, lead to loss of cognitive function, dementia, Alzheimer's disease, Parkinson's disease, and other neurodegenerative diseases.
Because neurodegenerative diseases primarily affect older adults, and because vitamin C is already known to play a role in brain health, a Japanese research team wanted to investigate the connection more closely.
The new study included more than 2,000 Japanese participants over age 64 whose blood levels of vitamin C were measured. Using MRI scans, the researchers measured the participants' gray and white matter volumes as well as their total brain volume. They also measured a group of interconnected brain regions known as the DMN (Default Mode Network), which plays an important role in attention, social understanding, autobiographical memory, and other cognitive functions.
The analysis was then adjusted for various confounding factors, including skull size, age, sex, physical activity, chronic diseases, and education level.
Lower vitamin C levels are associated with less gray matter
The study revealed that participants with lower levels of vitamin C in their blood tended to have reduced gray matter volume and weaker connections in the interconnected brain regions of the DMN. According to the researchers, higher levels of vitamin C in the blood may potentially help support cognitive function and healthy brain aging. The new study therefore sheds new light on why a diet rich in vitamin C may play a supportive role in brain health and thereby help prevent age-related cognitive decline and neurodegenerative diseases in older adults.

Vitamin C supports brain health through multiple functions

The brain is one of the organs with the highest concentrations of vitamin C because of its relatively high requirements. In the introduction to the new study, the researchers explain how vitamin C supports brain health through the following functions:

• It plays a role in the formation of collagen, where deficiencies can cause connective tissue to become loose, with a risk of poor circulation and fragile blood vessels.
• It is involved in many enzymatic reactions that also take place in the brain.
• It helps regulate nerve cell signaling.
• It is involved in the synthesis of peptide hormones that regulate blood sugar, metabolism, and other processes.
• It is involved in the brain's cholesterol homeostasis, as a healthy brain—and especially the nerve fibers in the white matter—contains a great deal of cholesterol.
• It functions as a powerful antioxidant that protects vulnerable cholesterol, nerve cells, and other cells from damage caused by free radicals and oxidative stress.

Vitamin C's ability to neutralize free radicals is particularly important in the fat- and cholesterol-rich brain. This is because the brain has a high rate of blood flow and is highly exposed to free radicals, which increase, among other things, as part of the aging process.
Vitamin C also plays a role in the immune system, which should protect the body and brain against harmful microorganisms and toxins. As part of the immune system and as a powerful antioxidant, vitamin C also helps protect the brain against chronic inflammation, which can occur in depression and many neurodegenerative diseases.
In the classic deficiency disease known as scurvy, people can die from internal bleeding. Before this occurs, severe fatigue, depression, and other psychological changes may also develop. Although scurvy is rare today, many people apparently suffer from subclinical scurvy, with bruising and bleeding gums being common visible signs. According to the new study, attention should also be paid to cognitive changes resulting from greater or lesser degrees of vitamin C deficiency.

Vitamin C sources, recommendations, and needs

Because vitamin C is a water-soluble vitamin, it should be consumed daily through fresh food sources such as citrus fruits, berries, bell peppers (especially red peppers), cruciferous vegetables (broccoli, cabbage, radishes, and arugula), spinach, tomatoes, garlic, and other sources.
The official daily recommendation is 80 micrograms. However, aging, stress, smoking, infections, chronic diseases, and many medications may increase the need.
For example, a previous study showed that a daily intake of 500 micrograms of vitamin C combined with vitamin E can reduce the incidence of Alzheimer's disease when the supplements are taken for more than three years.
In any case, the goal is to get enough vitamin C through a healthy diet and/or supplements so that the brain and nervous system receive an adequate supply.

References:

Haruka Nagaya et al. Plasma vitamin C levels are associated with brain structural networks on MRI: a large control study. PLOS One 2026

PLOS. Scientists discover a surprising link between vitamin C and brain health. ScienceDaily 2026