Ascorbic Acid, also referred to as vitamin C, is essential for various physiological functions essential for maintaining overall health and vitality. Humans lack the ability to synthesize Ascorbic Acid independently, so we rely on dietary sources or supplementation to fulfill their requirements.
Widely recognized for its potent antioxidant properties, Ascorbic Acid is a formidable defender against free radicals, harmful molecules implicated in the development of numerous chronic diseases.
Beyond its antioxidative role, Ascorbic Acid plays a pivotal part in collagen synthesis, facilitating wound healing and sustaining the integrity of the skin, bones, and connective tissues.
It is also involved in iron absorption, and therefore holds significance in red blood cell production and oxygen transport.
Additionally, its immune-modulating effects enhance the body's defenses against infections and illnesses.
This article explores the multifaceted nature of Ascorbic Acid, encompassing its structure, functions, testing methods, clinical significance, and strategies for optimizing its levels to promote optimal health.
Ascorbic Acid, or ascorbic acid, is a vital water-soluble nutrient that serves multiple essential functions in the human body. It is found in high concentrations in the adrenal glands, pituitary gland, brain, leukocytes, and eyes. Additionally, Ascorbic Acid is distributed in the extracellular fluids such as plasma, cerebrospinal fluid, and interstitial fluid. [5.]
As a potent antioxidant it combats oxidative stress by neutralizing harmful free radicals and reactive oxygen species, safeguarding cellular health and reducing oxidative damage.
Beyond its antioxidant role, Ascorbic Acid is integral to collagen synthesis, playing a crucial part in maintaining the structural integrity of skin, blood vessels, bones, and connective tissues.
Moreover, it facilitates the absorption of non-heme iron from dietary sources, thereby supporting the production of red blood cells and ensuring efficient oxygen transport throughout the body.
Humans rely on dietary intake for Ascorbic Acid as the body cannot synthesize it independently: citrus fruits, berries, tomatoes, potatoes, and leafy greens are excellent natural sources.
Absorption of Ascorbic Acid primarily occurs in the distal ileum of the small intestine through an energy-dependent process, involving both simple diffusion and active transport mechanisms.
While the absorption rate is typically high for dietary doses up to 100 mg/day, about 70-90%, it diminishes to about 50% with higher doses, especially exceeding 1 g/day. [5.]
Within the body Ascorbic Acid acts as a cofactor, enzyme complement, and co-substrate in various metabolic reactions, further reinforcing its indispensable role in biochemical processes.
Notably, it enhances the bioavailability of other nutrients such as vitamin E, glutathione and folic acid, while also exhibiting anti-inflammatory properties and supporting immune function.
However, excessive intake beyond recommended levels may lead to adverse effects including gastrointestinal disturbances, emphasizing the importance of balanced supplementation.
The RDA of Ascorbic Acid is 90 mg a day for men and 75 mg a day for women. It is set at 85 mg a day in pregnancy, and 100 mg a day in lactation. [5.]
Fruits and vegetables are rich sources of Ascorbic Acid.
Fruits:
Vegetables:
Ascorbic Acid supplements come in various forms, each with its own advantages and considerations.
The most common form is ascorbic acid, which is readily absorbed by the body and widely available.
Sodium ascorbate, a buffered form of Ascorbic Acid, is gentler on the stomach and may be preferable for those with sensitive digestive systems. Calcium ascorbate is another buffered form, offering the added benefit of calcium supplementation. Other mineral ascorbates may also be available.
Ester-C®, a patented form of Ascorbic Acid, contains calcium ascorbate and other compounds, potentially enhancing its absorption and retention in the body.
Liposomal Ascorbic Acid, encapsulated in liposomes, may improve bioavailability and absorption of the water-soluble vitamin, making it a suitable option for those seeking maximum benefit from their supplementation. [4.]
Insufficient Dietary Intake
Ascorbic Acid supplementation may be necessary for individuals with limited access to fresh fruits and vegetables, such as those living in food deserts or undergoing certain dietary restrictions.
Increased Demand
Certain medical conditions or lifestyle factors including smoking, alcoholism, chronic diseases, or pregnancy can elevate the body's requirement for Ascorbic Acid.
Surgical Procedures
Supplementation may be recommended before and after surgery to support immune function and enhance wound healing.
Illness Recovery
Ascorbic Acid supplementation may aid in recovery from illnesses by supporting immune function and promoting tissue repair.
Prevention of Deficiency
Ascorbic Acid supplementation can help prevent deficiency-related conditions like scurvy, particularly in populations at risk.
Enhanced Iron Absorption
Ascorbic Acid can improve the absorption of dietary iron, making supplementation beneficial for individuals at risk of iron deficiency or anemia.
Antioxidant Support
Ascorbic Acid's antioxidant properties help neutralize free radicals, protecting cells from oxidative damage and reducing the risk of chronic diseases.
Skin Health
Ascorbic Acid supplementation may promote skin health by supporting collagen synthesis, helping to maintain skin elasticity and wound healing.
Stress Management
Ascorbic Acid supplementation may help mitigate the effects of stress by supporting adrenal gland function and reducing cortisol levels. [10.]
Allergy Relief
Some evidence suggests that Ascorbic Acid supplementation may alleviate symptoms of allergies by modulating immune responses and reducing histamine levels.
Exercise Performance
Ascorbic Acid supplementation may improve exercise performance and recovery by reducing muscle damage and inflammation, particularly in endurance athletes.
Cardiovascular Health
Ascorbic Acid supplementation may benefit cardiovascular health by reducing the risk of hypertension, improving endothelial function, and lowering cholesterol levels.
Eye Health
Ascorbic Acid's antioxidant properties may help protect against age-related macular degeneration and cataracts, supporting overall eye health.
Cognitive Function
Some research suggests that Ascorbic Acid supplementation may improve cognitive function and reduce the risk of neurodegenerative diseases like Alzheimer's.
Cancer Prevention
Ascorbic Acid's antioxidant properties may help reduce the risk of certain cancers by neutralizing free radicals and supporting immune function.
Ascorbic Acid levels are typically tested in blood as a plasma or serum sample. Some labs may offer intracellular assessment of Ascorbic Acid levels, which assesses the levels of Ascorbic Acid in circulating leukocytes. [2.]
Sometimes, ascorbic acid is tested in the urine.
Blood tests for Ascorbic Acid levels typically require a venipuncture. Fasting is recommended, and your healthcare provider may recommend avoiding certain foods or supplements for a period of time prior to getting your sample.
Special care may need to be taken by the phlebotomist to ensure accurate results.
Testing for Ascorbic Acid in urine helps to assess recent dietary intake and the body's saturation levels of this vitamin.
Unlike blood tests that reflect the body's stores of Ascorbic Acid, urine tests indicate how much vitamin C is being excreted and therefore, indirectly, how much is being consumed.
This type of testing can be particularly useful in cases where rapid assessment of dietary intake is needed, such as in nutritional studies or in clinical settings where malnutrition is suspected.
Reference ranges often vary according to labs, so it is important to interpret results according to the lab company used.
Common reference ranges for Ascorbic Acid in plasma is 0.6-2 mg/dL. [11.]
High levels of Ascorbic Acid are less common than deficiency, yet they can have clinical significance, especially for certain populations or contexts.
Chronic overconsumption of Ascorbic Acid supplements may lead to gastrointestinal disturbances including diarrhea, nausea, and abdominal cramps.
Excessive intake of Ascorbic Acid can also increase the risk of kidney stone formation, especially in individuals predisposed to oxalate stones.
Furthermore, high doses of Ascorbic Acid may interfere with certain laboratory tests, such as glucose monitoring, resulting in false-positive or false-negative results.
High doses of Ascorbic Acid may exacerbate certain medical conditions such as hemochromatosis, a genetic disorder characterized by excessive iron absorption.
Therefore, while Ascorbic Acid is generally well-tolerated, it is essential to use supplements judiciously and under the guidance of a healthcare professional to avoid adverse effects associated with high Ascorbic Acid levels.
Low levels of Ascorbic Acid, known as hypovitaminosis C, can have significant clinical implications due to its essential role in numerous physiological processes.
Deficiency in Ascorbic Acid can lead to scurvy, a condition characterized by weakness, fatigue, anemia, swollen gums, joint pain, and impaired wound healing. In severe cases, scurvy can progress to life-threatening complications such as hemorrhage and organ failure.
Beyond scurvy, suboptimal levels of Ascorbic Acid have been associated with increased susceptibility to infections, impaired wound healing, and compromised immune function.
Additionally, inadequate Ascorbic Acid intake may contribute to the development or exacerbation of chronic diseases such as cardiovascular disease, cancer, and neurodegenerative disorders.
Therefore, maintaining adequate Ascorbic Acid levels through dietary sources or supplementation is crucial for overall health and disease prevention.
Excessive intake of Ascorbic Acid, typically through supplements, can lead to several side effects. The most common side effects include gastrointestinal disturbances such as stomach cramps, nausea, and diarrhea.
High doses of Ascorbic Acid can also increase the risk of oxalate kidney stones in susceptible individuals, as vitamin C can convert to oxalate and combine with calcium in the kidneys.
Additionally, extremely high doses might result in nutrient imbalances, interfering with the absorption of other essential vitamins and minerals.
Click here to review testing options and order Ascorbic Acid testing.
Click here to review testing options for Ascorbic Acid as part of a comprehensive nutrient panel.
[1.] Abdullah M, Jamil RT, Attia FN. Ascorbic Acid (Ascorbic Acid) [Updated 2023 May 1]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK499877/
[2.] Emadi-Konjin P, Verjee Z, Levin AV, Adeli K. Measurement of intracellular Ascorbic Acid levels in human lymphocytes by reverse phase high performance liquid chromatography (HPLC). Clin Biochem. 2005 May;38(5):450-6. doi: 10.1016/j.clinbiochem.2005.01.018. PMID: 15820776.
[3.] Gonzalez MJ, Miranda-Massari JR, Olalde J. Ascorbic Acid and mitochondrial function in health and exercise. Molecular Nutrition and Mitochondria. Published online 2023:225-242. doi:https://doi.org/10.1016/b978-0-323-90256-4.00016-3
[4.] Gopi S, Balakrishnan P. Evaluation and clinical comparison studies on liposomal and non-liposomal ascorbic acid (Ascorbic Acid) and their enhanced bioavailability. J Liposome Res. 2021 Dec;31(4):356-364. doi: 10.1080/08982104.2020.1820521. Epub 2020 Oct 6. PMID: 32901526.
[5.] Institute of Medicine (US) Panel on Dietary Antioxidants and Related Compounds. Dietary Reference Intakes for Ascorbic Acid, Vitamin E, Selenium, and Carotenoids. Washington (DC): National Academies Press (US); 2000. 5, Ascorbic Acid. Available from: https://www.ncbi.nlm.nih.gov/books/NBK225480/
[6.] Maxfield L, Daley SF, Crane JS. Ascorbic Acid Deficiency. [Updated 2023 Nov 12]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK493187/
[7.] Moritz B., et al. The role of Ascorbic Acid in stress-related disorders. The Journal of Nutritional Biochemistry. 2020;85:108459. doi:https://doi.org/10.1016/j.jnutbio.2020.108459
[8.] National Institutes of Health. Ascorbic Acid. National Institutes of Health. Published March 26, 2021. https://ods.od.nih.gov/factsheets/VitaminC-HealthProfessional/
[9.] Otocka-Kmiecik A, Król A. The Role of Ascorbic Acid in Two Distinct Physiological States: Physical Activity and Sleep. Nutrients. 2020 Dec 21;12(12):3908. doi: 10.3390/nu12123908. PMID: 33371359; PMCID: PMC7767325.
[10.] Peters EM, Anderson R, Nieman DC, Fickl H, Jogessar V. Ascorbic Acid supplementation attenuates the increases in circulating cortisol, adrenaline and anti-inflammatory polypeptides following ultramarathon running. Int J Sports Med. 2001 Oct;22(7):537-43. doi: 10.1055/s-2001-17610. PMID: 11590482.
[11.] Ascorbic Acid (Ascorbic Acid): Reference Range, Interpretation, Collection and Panels. eMedicine. Published online June 13, 2023. Accessed March 19, 2024. https://emedicine.medscape.com/article/2088649-overview#a1