Every time we bite into a juicy orange or another citrus fruit, we probably aren’t thinking of all of the benefits that piece of fruit provides — and if we are, we might be thinking of vitamin C. Vitamin C may be one of the most recognizable vitamins and minerals of all, and its many benefits, including those related to immunity, are well-known. However, did you know that vitamin C is beneficial for our overall health beyond the role it plays in our immune systems?
In general, vitamins and minerals are fundamentally important for our bodies, as they are crucial for many different metabolic pathways that are related to energy production, brain health and oxygen transport, just to name a few important functions (Tardy et al., 2020). According to some studies, in addition to the commonly known role it plays in our immunity, vitamin C is also important for brain health. When it comes to the brain, vitamin C is known to:
- Demonstrate protective qualities by functioning as an antioxidant
- Be involved in processes affecting blood flow (e.g., collagen synthesis)
- Play a role in cognitive function
- Aid in mental alertness
Plenty of research exploring the effects of vitamin C on the body has been and continues to be conducted, and there have been some interesting results revealing how important vitamin C is for our physical well-being. Below, we will explore what vitamin C is, as well as some of its potential effects on cognitive health and functions.
What is vitamin C?
Vitamin C, also known as ascorbic acid, is a water-soluble vitamin obtained through the diet. We are not able to make vitamin C on our own, so it is important that we eat a varied, balanced diet that will allow us to obtain adequate amounts of vitamin C. Fortunately, vitamin C is found naturally in many foods and is commonly added to others. It occurs naturally, for example, in fruits and vegetables, including oranges, tomatoes, peppers, strawberries, brussels sprouts and many more. It is also often added to fortified grains, such as some breakfast cereals. Vitamin C is also a common dietary supplement — and vitamin C supplementation actually increased in 2020 with the onset of the novel coronavirus, despite there being no scientific evidence that vitamin C is effective in the prevention or cure of COVID-19 at this time.
Vitamin C plays several important roles within our bodies, such as acting as an antioxidant that scavenges free radicals; the biosynthesis of collagen and some neurotransmitters; wound healing; immune function; and aiding our bodies in the absorption of non-heme iron (NIH, 2021). If you’re interested in learning more about the recommended intake of vitamin C, check out this fact sheet from the NIH. Older adults may be at an increased risk of developing vitamin C deficiency due to decreased intakes and other potential medical or health-related factors (Travica, et al., 2019).
Vitamin C deficiency is less common now than it used to be thanks to a better understanding of how to prevent deficiencies, as well as ready access to the vitamin through both naturally and scientifically fortified foods. Scurvy, the result of vitamin C deficiency, used to be more common and initially manifests with symptoms like increased fatigue; as it progresses, more symptoms present, such corkscrew hairs, poor wound healing, bleeding gums, depression and more (Travica, et al., 2019). Symptoms of scurvy generally don’t present until deficiency has lasted for weeks or months (Travica, et al., 2019)
Vitamin C and cognitive function
Many are aware of how vitamin C can affect immunity; however, vitamin C is also crucial for many other functions of the body, including cognitive function, and some studies have shown that there may be a positive association between vitamin C levels and total recall and recognition.
One study found a significant association between adequate vitamin C levels and an improvement in tasks that require focus, attention, decision speed and working memory, as well as better total recall and recognition in those with adequate vitamin C concentrations than in those with deficient concentrations (Travica, et al., 2019). Another article pointed out that vitamin C is important for proper brain development, as well as maintenance and protection (Harrison, 2012).
When the intake of vitamin C in our diets is low, our bodies will do everything they can to supply our brains with adequate amounts of vitamin C, and consequently, our bodies are very effective at maintaining adequate levels of the vitamin in our brains (Harrison & May, 2019). Deficiency symptoms involving the brain are usually related to the length of the deficiency rather than the severity of the deficiency alone (Travica, et al., 2019). Vitamin C aides in the synthesis (or development) of some neurotransmitters (i.e., chemical messengers that transport information) in the brain (Travica, et al., 2019). One of these is serotonin. Vitamin C is important for the production of serotonin, which acts as a mood stabilizer within our bodies (Travica, et al., 2019). Additionally, vitamin C plays a role in the development and regulation of epinephrine and norepinephrine, some of the hormones or neurotransmitters that are important for our “fight or flight” mechanisms (Tardy et al., 2020).
Some studies have demonstrated a cognitive plateau in individuals with plasma concentrations above a certain amount, indicating that exceeding the recommended dosage of vitamin C may not be beneficial for further cognitive improvements or functions, as our bodies will likely not be able to fully utilize or absorb this additional vitamin C, and it will likely be excreted through the urine (Travica, et al., 2019) (NIH, 2021).
Vitamin C is also crucial for the formation of collagen in the body, including in the brain. This is notable because collagen is important for blood vessel formation and the delivery of essential nutrients and oxygen to the brain (Travica, et al., 2019). Vitamin C is also known to enhance the synthesis of the endothelium, a layer of cells that lines the inside of blood vessels (May and Harrison, 2013).
Severe vitamin C deficiencies have been linked to vascular dysfunction (reduced or altered blood flow) and reduced rates of new blood vessel formation (Travica, et al., 2017).
Vitamin C is also involved in the formation and maintenance of the myelin sheath, a protective layer that forms around nerves and allows for electrical impulses to be transmitted (Travica, et al., 2019).
Additionally, vitamin C has been shown to support the biosynthesis of carnitine, which can be converted back and forth between acetyl-carnitine, which is able to cross the blood brain barrier and is eventually involved in the production of acetylcholine, an important factor for cerebral blood flow (Travica, et al., 2019)
Vitamin C as an antioxidant
Under certain physiologic conditions, vitamin C can act as an antioxidant. Antioxidants are able to donate electrons to unstable molecules in order to make them stable. This is a protective quality for our bodies.
There are many different kinds of antioxidants, including vitamin C. There are several occurrences in the body that naturally produce free radicals (these potentially reactive molecules), and our bodies are generally good at stabilizing and scavenging these molecules to maintain homeostasis. Metabolism is a natural occurrence that can create byproducts of free radicals, and because the brain metabolizes oxygen and nutrients, it experiences some of these byproducts. Within the brain, Vitamin C acts as a powerful antioxidant and scavenges these byproducts, offering protection to the cells of the brain (Travica, et al., 2019).
Vitamin C is also involved in the recycling vitamin E, another antioxidant that aids in the maintenance and protection of the brain (Travica, et al., 2019). One article noted that having adequate levels of vitamin C in the tissue provides protective antioxidant qualities (Tardy, et al., 2020). There are several different kinds of antioxidants, and our bodies are generally very effective at utilizing these antioxidants to maintain a state of homeostasis.
Vitamin C and mental alertness
Vitamin C deficiency can be associated with fatigue, confusion and depression, so an adequate intake of this vitamin may be important for mental health. Vitamin C also plays a crucial role in the reaction that creates the neurotransmitter norepinephrine from dopamine — think increased alertness, concentration and reaction time. Additionally, vitamin C is involved in energy production via beta oxidation, the process in which fatty acids are broken down to produce energy. Therefore, inadequate vitamin C can have an impact on energy as well (Tardy, et al., 2020).
In a study done in the U.K. on 15,000 healthy men and women, the results showed that those with the lowest levels of plasma vitamin C were more likely to get a poor score for their physical functional health on the validated Short Form Health Survey (Tardy, et al., 2020). These results are in line with some previous findings that have indicated that individuals who eat fruits and vegetables are associated with higher self-reported physical functional health (Tardy, et al., 2020).
The effects that vitamin C can have on brain function are still being researched, and more studies need to be conducted that use large sample sizes with human participants — but the most important thing to remember for our brain health is that we must supply our brains with adequate energy by eating a balanced and varied diet. Our brains are constantly doing a lot of work for us, and they require adequate fuel throughout the day. When we eat a balanced and varied diet, we are not only supplying our body with the fuel it needs; we are also supplying it with many other important elements, including vitamins — like vitamin C — and minerals that benefit us in a variety of ways, such as by acting as antioxidants; by serving as co-enzymes in many different pathways that are important to our overall health and well-being; and in many other functions throughout our bodies. So, remember to make sure you are giving your body — and your brain — enough fuel throughout the day, and eat your fruits and veggies!
Harrison F. E. (2012). A critical review of vitamin C for the prevention of age-related cognitive decline and Alzheimer’s disease. Journal of Alzheimer’s disease: JAD, 29(4), 711–726. https://doi.org/10.3233/JAD-2012-111853
Harrison, F. E., & May, J. M. (2009). Vitamin C function in the brain: vital role of the ascorbate transporter SVCT2. Free radical biology & medicine, 46(6), 719–730. https://doi.org/10.1016/j.freeradbiomed.2008.12.018
May, J. M., & Harrison, F. E. (2013). Role of vitamin C in the function of the vascular endothelium. Antioxidants & redox signaling, 19(17), 2068–2083. https://doi.org/10.1089/ars.2013.5205
NIH. (2021, March 26). Vitamin C Fact Sheet for Health Professionals. Retrieved from National Institutes of Health Office of Dietary Supplements: https://ods.od.nih.gov/factsheets/VitaminC-HealthProfessional/
Travica, N., Ried, K., Sali, A., Scholey, A., Hudson, I., & Pipingas, A. (2017). Vitamin C Status and Cognitive Function: A Systematic Review. Nutrients, 9(9), 960. https://doi.org/10.3390/nu9090960
Travica, N., Ried, K., Sali, A., Hudson, I., Scholey, A., & Andrew, P. (2019, April 2 ). Plasma Vitamin C Concentrations and Cognitive Function: A Cross-Sectional Study. Frontiers in Aging Neuroscience, 11(72), 1-21.
Tardy, A. L., Pouteau, E., Marquez, D., Yilmaz, C., & Scholey, A. (2020). Vitamins and Minerals for Energy, Fatigue and Cognition: A Narrative Review of the Biochemical and Clinical Evidence. Nutrients, 12(1), 228. https://doi.org/10.3390/nu12010228