What Is Vitamin C, and What Role Does It Play in Brain Health?

Vitamin C, also known as L-ascorbic acid, is a water-soluble nutrient that plays a crucial role in brain health and function.((Abdullah, Muhammad, Radia T. Jamil, and Fibi N. Attia. “Vitamin C (Ascorbic Acid).” In StatPearls. Treasure Island (FL): StatPearls Publishing, 2022. http://www.ncbi.nlm.nih.gov/books/NBK499877/.)) The brain contains the largest concentration of vitamin C of any major organ or tissue in the body. A deficiency can lead to cognitive impairment in people of all ages.((Travica, Nikolaj, Karin Ried, Avni Sali, Irene Hudson, Andrew Scholey, and Andrew Pipingas. 2019. “Plasma Vitamin c Concentrations and Cognitive Function: A Cross-Sectional Study.” Frontiers in Aging Neuroscience 11 (April). https://doi.org/10.3389/fnagi.2019.00072.))
Citrus fruits, certain vegetables, and white potatoes are some of the best food sources of vitamin C. The other option for getting vitamin C is through supplements, such as multivitamins.
A notable benefit of vitamin C is that it possesses potent antioxidant properties. The nutrient counteracts reactive oxygen species (ROS)–unstable molecules that can lead to oxidative stress, premature aging, healthy cell death, and disease.((Padayatty, Sebastian J., Arie Katz, Yaohui Wang, Peter Eck, Oran Kwon, Je-Hyuk Lee, Shenglin Chen, et al. “Vitamin C as an Antioxidant: Evaluation of Its Role in Disease Prevention.” Journal of the American College of Nutrition 22, no. 1 (February 2003): 18-35. https://doi.org/10.1080/07315724.2003.10719272.))((Alfadda, Assim A., and Reem M. Sallam. “Reactive Oxygen Species in Health and Disease.” Journal of Biomedicine & Biotechnology 2012 (2012): 936486. https://doi.org/10.1155/2012/936486.)) Similarly, vitamin C appears to recycle other antioxidants, such as vitamin E.((Traber, Maret G., and Jan F. Stevens. “Vitamins C and E: Beneficial Effects from a Mechanistic Perspective.” Free Radical Biology & Medicine 51, no. 5 (September 1, 2011): 1000-1013. https://doi.org/10.1016/j.freeradbiomed.2011.05.017.))
Another benefit of vitamin C is that it promotes brain-derived neurotrophic factor (BDNF) expression.((Miranda, Magdalena, Juan Facundo Morici, María Belén Zanoni, and Pedro Bekinschtein. 2019. “Brain-Derived Neurotrophic Factor: A Key Molecule for Memory in the Healthy and the Pathological Brain.” Frontiers in Cellular Neuroscience 13 (August). https://doi.org/10.3389/fncel.2019.00363.))((Tanra, Andi Jayalangkara, Herwina Sabaruddin, Kristian Liaury, and Andi Alfian Zainuddin. 2021. “Effect of Adjuvant Vitamin c on Brain-Derived Neurotrophic Factor Levels and Improvement of Negative Symptoms in Schizophrenic Patients.” Open Access Macedonian Journal of Medical Sciences 9 (T3): 353-57. https://doi.org/10.3889/oamjms.2021.7086.)) The nutrient also serves crucial structural functions in the brain through cell membrane construction.
If the above benefits weren’t enough, vitamin C also contributes to producing crucial hormones and neurotransmitters for the brain and neurons.((Padayatty, SJ, and M Levine. 2016. “Vitamin C: The Known and the Unknown and Goldilocks.” Oral Diseases 22 (6): 463-93. https://doi.org/10.1111/odi.12446.)) As such, the nutrient plays a vital role in signaling transmission.
Despite all of vitamin C’s benefits, it is easy to overlook its crucial role when considering other, flashier supplements on the market.

The Missing Links for Brain Health

How often have you come across seemingly beneficial compounds touted to improve your cognition, memory, focus, etc.? Like most, you’ve probably seen your fair share of such products, and you might have even tried some of them. But what were the results? You probably felt the same, right? If anything, you might have experienced some benefits that can easily be attributed to the placebo effect–expect something to be beneficial, and it will be.
Some people choose to blame themselves. Maybe they didn’t take the supplement correctly or fell into the small percentage of non-responders. Others blame the supplier. Perhaps the batch wasn’t as good, and the next one will deliver the promised benefits.
Sadly, in almost all cases, the problem has nothing to do with the supplement or the person but with something else entirely:
Inadequate levels of essential vitamins and minerals the body needs to function at its best.
A notable example is tryptophan–an essential amino acid with numerous roles in the body, including serving as a precursor in serotonin synthesis.((Richard, Dawn M, Michael A Dawes, Charles W Mathias, Ashley Acheson, Nathalie Hill-Kapturczak, and Donald M Dougherty. 2009. “L-Tryptophan: Basic Metabolic Functions, Behavioral Research and Therapeutic Indications.” International Journal of Tryptophan Research 2 (January): IJTR.S2129. https://doi.org/10.4137/ijtr.s2129.)) Serotonin is a neurotransmitter that regulates sleep, mood, appetite, bone health, and even sexual desire.((Berger, Miles, John A Gray, and Bryan L Roth. 2009. “The Expanded Biology of Serotonin.” Annual Review of Medicine 60 (1): 355-66. https://doi.org/10.1146/annurev.med.60.042307.110802.))

Prevailing wisdom suggests that we can take tryptophan or consume more tryptophan-rich foods to boost serotonin levels and reap the neurotransmitter’s benefits. But many miss the fact that, among other nutrients, vitamin C likely plays a significant role in serotonin synthesis, so having adequate levels of the nutrient should be your first consideration.((Prerana Gupta, Sanchit Tiwari, Jigar Haria. Relationship Between Depression and Vitamin C Status: A Study on Rural Patients From Western Uttar Pradesh in India, International Journal Of Scientific Study, Vol 1 No 4 (2014): Volume 1, Issue 4 – January))

An In-Depth Look at Vitamin C’s Effects on the Brain

We took a brief look at vitamin C’s effects on the brain in a previous point, so let’s explore the unique mechanisms a bit further:

1. Antioxidant Effects

A huge reason why vitamin C is so beneficial for our health, well-being, and longevity is that the nutrient possesses potent antioxidant properties ((Padayatty, Sebastian J., Arie Katz, Yaohui Wang, Peter Eck, Oran Kwon, Je-Hyuk Lee, Shenglin Chen, et al. “Vitamin C as an Antioxidant: Evaluation of Its Role in Disease Prevention.” Journal of the American College of Nutrition 22, no. 1 (February 2003): 18-35. https://doi.org/10.1080/07315724.2003.10719272.)). To understand the significance of vitamin C’s antioxidant abilities, we first have to look at free radicals.
Each day, your body generates countless free radicals–unstable molecules with some health functions.(( Pham-Huy, Lien Ai, Hua He, and Chuong Pham-Huy. “Free Radicals, Antioxidants in Disease and Health.” International Journal of Biomedical Science: IJBS 4, no. 2 (June 2008): 89-96.)) Unfortunately, accumulating too many free radicals can be harmful as these molecules damage healthy body cells, accelerate aging, and increase the risk of cancer, diabetes, and other diseases.((Alfadda, Assim A., and Reem M. Sallam. “Reactive Oxygen Species in Health and Disease.” Journal of Biomedicine & Biotechnology 2012 (2012): 936486. https://doi.org/10.1155/2012/936486.))((Saha, Subbroto Kumar, Soo Bin Lee, Jihye Won, Hye Yeon Choi, Kyeongseok Kim, Gwang-Mo Yang, Ahmed Abdal Dayem, and Ssang-goo Cho. 2017. “Correlation between Oxidative Stress, Nutrition, and Cancer Initiation.” International Journal of Molecular Sciences 18 (7): 1544. https://doi.org/10.3390/ijms18071544.))
The body has natural antioxidant properties that control free radical levels, but numerous foods are also good sources of antioxidant compounds. Getting antioxidants through foods and supplements is beneficial because it improves your body’s ability to deal with oxidative stress.
Antioxidants are also crucial for the brain because the organ is susceptible to high amounts of oxidative stress, resulting in functional decline.((Covarrubias-Pinto, Adriana, Aníbal Acuña, Felipe Beltrán, Leandro Torres-Díaz, and Maite Castro. 2015. “Old Things New View: Ascorbic Acid Protects the Brain in Neurodegenerative Disorders.” International Journal of Molecular Sciences 16 (12): 28194-217. https://doi.org/10.3390/ijms161226095.)) According to research, the amygdala and hippocampus appear to be the most vulnerable to oxidative stress, and their functions decline quicker than those of other brain regions.((Salim, Samina. 2016. “Oxidative Stress and the Central Nervous System.” Journal of Pharmacology and Experimental Therapeutics 360 (1): 201-5. https://doi.org/10.1124/jpet.116.237503.)) The amygdala plays a crucial role in regulating our emotions, and the hippocampus is vital for memory and learning.
Vitamin C serves a crucial antioxidant function in the central nervous system. Having adequate levels of the nutrient can protect the brain and reduce oxidative stress, allowing it to carry out its functions well. The nutrient is also known for its ability to generate vitamin E from its oxidized form, leading to a more diverse antioxidant profile in the body.((Traber, Maret G., and Jan F. Stevens. “Vitamins C and E: Beneficial Effects from a Mechanistic Perspective.” Free Radical Biology & Medicine 51, no. 5 (September 1, 2011): 1000-1013. https://doi.org/10.1016/j.freeradbiomed.2011.05.017.))

2. Co-Factor for Enzyme Reactions

Each day, the brain carries out processes that generate necessary compounds, allowing us to function, think, recall things, and solve problems. Despite not making headlines often, vitamin C plays an integral role because the nutrient is a reducing agent. Vitamin C donates electrons to molecules, allowing the correct reactions to occur.
Aside from its antioxidant properties, vitamin C’s ability to donate electrons makes it a valuable co-factor for enzyme reactions in the brain.((Abdullah, Muhammad, Radia T. Jamil, and Fibi N. Attia. “Vitamin C (Ascorbic Acid).” In StatPearls. Treasure Island (FL): StatPearls Publishing, 2022. http://www.ncbi.nlm.nih.gov/books/NBK499877/.))((Padayatty, SJ, and M Levine. 2016. “Vitamin C: The Known and the Unknown and Goldilocks.” Oral Diseases 22 (6): 463-93. https://doi.org/10.1111/odi.12446.)) A notable example here is the nutrient’s ability to maintain enzyme-bound metals in their reduced forms, resulting in the synthesis of essential molecules (enzymes). The two types of enzymes that result from these processes are dioxygenases and monooxygenases.((Padayatty, SJ, and M Levine. 2016. “Vitamin C: The Known and the Unknown and Goldilocks.” Oral Diseases 22 (6): 463-93. https://doi.org/10.1111/odi.12446.))
Both enzymes have crucial roles in our health, energy levels, ability to synthesize collagen (the most abundant protein in the body), and more. For instance, some dioxygenases play a role in gene expression and require vitamin C to serve as a co-factor.((Padayatty, SJ, and M Levine. 2016. “Vitamin C: The Known and the Unknown and Goldilocks.” Oral Diseases 22 (6): 463-93. https://doi.org/10.1111/odi.12446.))
One likely explanation for impaired wound healing and chronic fatigue in people with low vitamin C levels is that enzymatic reactions are impaired, leading to inadequate catecholamine, collagen, and carnitine synthesis.

3. Improvements in BDNF Expression

Brain-derived neurotrophic factor (BDNF) is an essential molecule with functions in brain plasticity related to learning.((Miranda, Magdalena, Juan Facundo Morici, María Belén Zanoni, and Pedro Bekinschtein. 2019. “Brain-Derived Neurotrophic Factor: A Key Molecule for Memory in the Healthy and the Pathological Brain.” Frontiers in Cellular Neuroscience 13 (August). https://doi.org/10.3389/fncel.2019.00363.)) BDNF levels can range significantly in healthy individuals because numerous things affect the molecule’s expression.
According to some research, vitamin C supplementation can improve BDNF expression, allowing the brain to form new connections, repair itself, and protect its healthy cells. In one study, 57 schizophrenic patients were given either vitamin C or a placebo for eight weeks.((Tanra, Andi Jayalangkara, Herwina Sabaruddin, Kristian Liaury, and Andi Alfian Zainuddin. 2021. “Effect of Adjuvant Vitamin c on Brain-Derived Neurotrophic Factor Levels and Improvement of Negative Symptoms in Schizophrenic Patients.” Open Access Macedonian Journal of Medical Sciences 9 (T3): 353-57. https://doi.org/10.3889/oamjms.2021.7086.)) Researchers noted significant improvements in BDNF expression in the patients who received vitamin C. Furthermore, the same subjects experienced fewer negative symptoms related to their condition.
In another paper from 2005, researchers noted improvements in BDNF expression in the presence of vitamin C.((Grant, Melissa M., Vicki S. Barber, and Helen R. Griffiths. 2005. “The Presence of Ascorbate Induces Expression of Brain Derived Neurotrophic Factor in SH-SY5Y Neuroblastoma Cells after Peroxide Insult, Which Is Associated with Increased Survival.” PROTEOMICS 5 (2): 534-40. https://doi.org/10.1002/pmic.200300924.)) The authors of the study noted:
“Enhanced expression of BDNF may contribute to the protective effects of ascorbate against oxidative stress in neuronal cells.”

4. Protection Against Neurodegenerative Disease

As discussed above, vitamin C is a crucial antioxidant for the central nervous system. Under normal circumstances, glial reservoirs release vitamin C into the synaptic cleft (the space between neurons), and neurons utilize the nutrient.((Covarrubias-Pinto, Adriana, Aníbal Acuña, Felipe Beltrán, Leandro Torres-Díaz, and Maite Castro. 2015. “Old Things New View: Ascorbic Acid Protects the Brain in Neurodegenerative Disorders.” International Journal of Molecular Sciences 16 (12): 28194-217. https://doi.org/10.3390/ijms161226095.)) A notable function of the nutrient is to ‘pick up’ reactive oxygen species that accumulate from neuron activity, protecting brain cells from oxidative stress.
Aside from its antioxidant functions, vitamin C is a crucial molecule in the central nervous system. The nutrient can alter neuronal metabolism, forcing cells to switch from glucose to lactate to sustain activity. According to another paper, this switch is beneficial because lactate works as a signaling molecule, modulating neuron functions related to excitability, memory consolidation, and brain plasticity.((Magistretti, Pierre J., and Igor Allaman. 2018. “Lactate in the Brain: From Metabolic End-Product to Signalling Molecule.” Nature Reviews Neuroscience 19 (4): 235-49. https://doi.org/10.1038/nrn.2018.19.))
According to the previous paper, oxidative stress plays a significant role in neurodegeneration, and vitamin C could be the critical nutrient that stands between neurons and reactive oxygen species.((Covarrubias-Pinto, Adriana, Aníbal Acuña, Felipe Beltrán, Leandro Torres-Díaz, and Maite Castro. 2015. “Old Things New View: Ascorbic Acid Protects the Brain in Neurodegenerative Disorders.” International Journal of Molecular Sciences 16 (12): 28194-217. https://doi.org/10.3390/ijms161226095.)) In the authors’ words:
“Neurons are sensitive to ascorbic acid deficiency since they have an oxidative metabolism rate 10-fold higher than glial cells. It has been suggested that ascorbic acid has a neuroprotective role due to the existence of homeostatic mechanisms which maintain high concentrations of ascorbic acid in CSF and neurons.”
The brain needs to maintain high concentrations of vitamin C to prevent ROS accumulation and the resulting oxidative stress that speeds up neurodegeneration. The same paper notes that higher ROS levels are observed in the brain tissue of patients with Alzheimer’s, Parkinson’s, and Huntington’s disease.((Covarrubias-Pinto, Adriana, Aníbal Acuña, Felipe Beltrán, Leandro Torres-Díaz, and Maite Castro. 2015. “Old Things New View: Ascorbic Acid Protects the Brain in Neurodegenerative Disorders.” International Journal of Molecular Sciences 16 (12): 28194-217. https://doi.org/10.3390/ijms161226095.))

5. Facilitation of Nervous System Activity

Vitamin C plays an essential role in neuron maturation and the formation of myelin–a protective sheath that envelops nerves in the brain and spinal cord.((“Does Vitamin c Influence Neurodegenerative Diseases and Psychiatric Disorders?” 2017. Nutrients 9 (7): 659. https://doi.org/10.3390/nu9070659.)) As such, the nutrient plays an essential role in protecting nerve cells and speeding up impulse transmission, which is crucial for cognitive performance.
Furthermore, vitamin C is a co-factor for crucial enzymatic reactions related to the nervous system.((Harrison, Fiona E., and James M. May. 2009. “Vitamin c Function in the Brain: Vital Role of the Ascorbate Transporter SVCT2.” Free Radical Biology and Medicine 46 (6): 719-30. https://doi.org/10.1016/j.freeradbiomed.2008.12.018.)) For instance, the nutrient plays a role in producing essential neurotransmitters and controls the release of these compounds in nerve cells.
The above mechanisms are supported by research on humans. In a systematic review from 2017, researchers examined 50 studies carried out between 1980 and 2017.((Travica, Nikolaj, Karin Ried, Avni Sali, Andrew Scholey, Irene Hudson, and Andrew Pipingas. 2017. “Vitamin c Status and Cognitive Function: A Systematic Review.” Nutrients 9 (9). https://doi.org/10.3390/nu9090960.)) Among the studies, 36 were conducted on healthy individuals and 14 on folks with cognitive impairment. Cognition was assessed in several ways, and vitamin C status was determined using various questionnaires or looking at plasma levels.
Researchers noted a link between higher vitamin C concentration and higher cognitive performance. The authors of the review also noted:
“Qualitative assessment revealed a potential association between plasma vitamin C concentrations and cognition.”

Final Thoughts and Dosage Information

Scurvy, also known as severe vitamin C deficiency, is rare today. According to data, vitamin C deficiency affects fewer than 7.1 percent of people in the United States.((Maxfield, Luke, and Jonathan S. Crane. “Vitamin C Deficiency.” In StatPearls. Treasure Island (FL): StatPearls Publishing, 2022. http://www.ncbi.nlm.nih.gov/books/NBK493187/.)) Still, there is a risk, and even if a person doesn’t show the typical signs, such as bleeding gums and chronic fatigue, it doesn’t mean they aren’t somewhat deficient.
The bare minimum vitamin C dose stands at just 10 mg daily for scurvy prevention. For reference, that’s a fourth of a tiny orange. But, research suggests that covering the bare minimum is far from enough.
The recommended daily intake (RDA) is 90 mg daily for men and 75 mg for women, or up to nine times the recommended amount for avoiding scurvy. For pregnant and breastfeeding women, the dosages increase to 85 and 120 mg, respectively. However, research suggests that these levels are still far from enough to cover all of vitamin C’s functions.
Many clinical trials use anywhere between 500 mg and 5,000 mg of vitamin C per day, depending on the condition and its severity. Additionally, some studies include vitamin C as part of a multivitamin blend.
Keep in mind that there is no one-size-fits-all dosage. Some people are perfectly fine with the RDA and don’t need to supplement at all. Others may require higher dosages, especially those under oxidative stress or involved in tasks that demand more vitamin C.
It’s worth noting that large doses of vitamin C (2,000 mg and above) might cause stomach cramps and diarrhea. However, the dose varies from person to person, and what causes side effects in one individual might not do the same in another.