Vitamin C (AKA, L-ascorbic acid), is an essential water-soluble nutrient. It’s one of the most popular supplements due to its safety, antioxidant effects, and affordable price.
The need to include fresh plants and fruits high in vitamin C for optimal health was known for a very long time. In 1536, Jacques Cartier boiled the needles of arbor vitae tree to make a tea that saved his men from dying of scurvy – severe vitamin C deficiency.
Today, vitamin C is most often supplemented to boost immunity and ward off the common cold. However, it doesn’t appear to be able to reduce the frequency of colds in healthy individuals. This only works in athletes, who can cut their risk of getting the cold in half by supplementing with the nutrient.
Taking vitamin C does appear effective at reducing the duration of a cold by around 14% in any individual, when used as a preventative measure or in the early stages of a cold. Some people also like to superload vitamin C (10g+ per day) to ward off the common cold. However, there’s very little scientific evidence to support this usage.
Vitamin C has a unique ability to be both a pro-oxidant and antioxidant, depending on what your body needs. Its structure allows it to regulate cortisol, fight depression, and provide neuroprotective effects. Its antioxidant effects can also protect testes from free radicals – preserving testosterone levels in the process.
Reported Effects of Vitamin C
1. Might Help Regulate Blood Pressure
High blood pressure is a potentially life threatening condition that significantly increases the risk of heart disease.
Studies show that vitamin C contributes to normal blood pressure in both healthy individuals and those with high blood pressure.
Animal study found that vitamin C supplementation helps relax blood vessels that carry blood from the heart, which resulted in lower blood pressure levels. [1]
Furthermore, a review of 29 human studies reported that supplementing vitamin C reduced systolic and diastolic blood pressure by 1.5-3.8mmHg on average, in healthy individuals. Those who had high blood pressure experienced a reduction in blood pressure by 1.7-4.9 mmHg on average. [2]
Although these results look promising, it’s still unclear whether these effects are long-term. People with elevated blood pressure should never rely on vitamin C alone for treating the condition.
2. Strengthens the Immune System
Most people who take vitamin C do it with the goal of boosting their immunity. It’s well-known that vitamin C is involved in many parts of the immune system.
For example, vitamin C encourages the production of lymphocytes or white blood cells, as well as phagocytes which protect the body from infection. [6] It also protects white blood cells themselves from harmful free radicals, along with boosting their function.
Interestingly, vitamin C is also used as a part of your skin’s defense system. It acts as an antioxidant that strengthens the skin’s barriers. Some studies have shown that this bioactivity might lead to faster wound healing. [7]
More importantly, those who’re deficient in vitamin C are suggested to be at higher risk of poor health outcomes.
For example, vitamin C levels tend to be lower in people with pneumonia. Supplementing the water-soluble nutrient is shown to shorten the recovery time. [8]
3. Protects Cognition
Dementia is a condition that typically affects the older population and manifests as poor memory and thinking.
Studies suggest that inflammation in the central nervous system can raise the risk of dementia. [3]
Vitamin C is a potent antioxidant. As such, it helps lower inflammation caused by oxidative stress. Low levels of vitamin C are associated with an impaired cognitive function.
A number of studies show that individuals with dementia may have lower than normal blood levels of vitamin C. [4, 5]
Moreover, high vitamin C intake has a protective effect on thinking and memory as the brain ages. However, more studies are needed to fully grasp vitamin C’s effects on the nervous system in the long-term.
4. Contributes to Improved Overall Health
Vitamin C is often used as a reference antioxidant in studies. It’s one of the most powerful vitamins for improving body’s defenses.
Most of the benefits of vitamin C stem from its ability to neutralize unstable free radicals. When too many free radicals amass in the body, a state known as “oxidative stress” ensues, which can potentially trigger the development of different chronic diseases. [9]
Research shows that taking more vitamin C can boost blood antioxidant levels by up to 30%. This aids the body’s natural defenses and contributes to better health overall. [10]
Common Supplements that Contain Vitamin C
Vitamin C comes in many forms. These include:
- Ascorbic acid.
- Mineral ascorbates: sodium ascorbate, calcium ascorbate, magnesium ascorbate.
- Vitamin C with bioflavonoids.
- Ascorbyl palmitate.
Vitamin C is often taken as a standalone supplement, but also as a part of a broader formula, such as a multivitamin.
Speak with your MD if you aren’t sure which type of vitamin C is best for you.
Side Effects of Vitamin C Supplementation – Are there Reported Side Effects?
Vitamin C is considered to be a safe supplement. It’s water soluble, which means your body doesn’t store it. This makes it safer than some fat-soluble vitamins, such as vitamin A, which can build up to harmful amounts in the body when taken in excess.
However, vitamin C can also potentially lead to side effects when taken in extremely large doses. The most common ones are diarrhea and digestive distress.
Vitamin C Dosage
Vitamin C is well-tolerated by most people in doses up to 2,000mg per day. This dose is often used in studies that look into vitamin C’s effects on health.
The following are the official RDA’s for vitamin C. These are the minimum amounts of the nutrient you should be taking every day:
| Kids (1–3 years) | 15 mg |
|---|---|
| Kids (4–8 years) | 25 mg |
| Adolescents (9–13 years) | 45 mg |
| Teens (14–18 years) | 65–75 mg |
| Adult women (aged 19 and older) | 75 mg |
| Adult men (aged 19 and older) | 90 mg |
| Pregnant women (aged 19 and older) | 85 mg |
| Breastfeeding women (aged 19 and older) | 120 mg |
Scientific References
- Ettarh RR, Odigie IP, Adigun SA. Vitamin C lowers blood pressure and alters vascular responsiveness in salt-induced hypertension. Can J Physiol Pharmacol. 2002;80(12):1199‐1202. doi:10.1139/y02-147
- Juraschek SP, Guallar E, Appel LJ, Miller ER 3rd. Effects of vitamin C supplementation on blood pressure: a meta-analysis of randomized controlled trials. Am J Clin Nutr. 2012;95(5):1079‐1088. doi:10.3945/ajcn.111.027995
- Bennett S, Grant MM, Aldred S. Oxidative stress in vascular dementia and Alzheimer’s disease: a common pathology. J Alzheimers Dis. 2009;17(2):245‐257. doi:10.3233/JAD-2009-1041
- von Arnim CA, Herbolsheimer F, Nikolaus T, et al. Dietary antioxidants and dementia in a population-based case-control study among older people in South Germany. J Alzheimers Dis. 2012;31(4):717‐724. doi:10.3233/JAD-2012-120634
- Charlton KE, Rabinowitz TL, Geffen LN, Dhansay MA. Lowered plasma vitamin C, but not vitamin E, concentrations in dementia patients. J Nutr Health Aging. 2004;8(2):99‐107.
- Huijskens MJ, Walczak M, Koller N, et al. Technical advance: ascorbic acid induces development of double-positive T cells from human hematopoietic stem cells in the absence of stromal cells. J Leukoc Biol. 2014;96(6):1165‐1175. doi:10.1189/jlb.1TA0214-121RR
- Desneves KJ, Todorovic BE, Cassar A, Crowe TC. Treatment with supplementary arginine, vitamin C and zinc in patients with pressure ulcers: a randomised controlled trial. Clin Nutr. 2005;24(6):979‐987. doi:10.1016/j.clnu.2005.06.011
- Bakaev VV, Duntau AP. Ascorbic acid in blood serum of patients with pulmonary tuberculosis and pneumonia. Int J Tuberc Lung Dis. 2004;8(2):263‐266.
- Pham-Huy LA, He H, Pham-Huy C. Free radicals, antioxidants in disease and health. Int J Biomed Sci. 2008;4(2):89‐96.
- Kim MK, Sasazuki S, Sasaki S, Okubo S, Hayashi M, Tsugane S. Effect of five-year supplementation of vitamin C on serum vitamin C concentration and consumption of vegetables and fruits in middle-aged Japanese: a randomized controlled trial. J Am Coll Nutr. 2003;22(3):208‐216. doi:10.1080/07315724.2003.10719295