Vitamin C, also known as ascorbic acid , is a water-soluble vitamin essential for many processes in the body. It is particularly known for its antioxidant properties and its role in supporting the immune system. Vitamin C also aids in collagen formation, wound healing, and iron absorption. Because the human body cannot produce vitamin C, it must be obtained through food or supplements. In this article, you'll learn why vitamin C is important, its benefits, and how to use it safely.
What is Vitamin C?
Vitamin C is a water-soluble vitamin found in many fruits and vegetables. It acts as a powerful antioxidant, protecting cells from oxidative stress caused by free radicals. Free radicals are produced in the body through normal metabolic processes as well as environmental factors such as smoking or pollution. Vitamin C not only supports the immune system but also plays a crucial role in collagen production, which is essential for healthy skin, joints, and blood vessels [1].
Synonyms for Vitamin C
Vitamin C is also known as ascorbic acid , a chemical name for the form of the vitamin used in dietary supplements and fortified foods. Ascorbic acid is available in both synthetic and natural forms and is biologically equivalent, meaning the body can utilize both forms in the same way [2].
Where does Vitamin C come from?
Vitamin C occurs naturally in many fruits and vegetables, including citrus fruits such as oranges, lemons, and grapefruit, as well as strawberries, kiwis, peppers, and broccoli. Because vitamin C is water-soluble and the body doesn't store it, it's important to regularly consume foods rich in vitamin C to meet your needs [3].
How is Vitamin C produced?
Vitamin C is either obtained from natural sources such as fruits and vegetables or produced synthetically. Synthetic vitamin C used in supplements is often made from glucose and chemically converted into ascorbic acid. Both forms are chemically identical and utilized by the body in the same way [4].
Health benefits of Vitamin C
Vitamin C and the immune system
Vitamin C is known for its role in supporting the immune system. It promotes the production and function of white blood cells, which play a key role in fighting infections. Furthermore, vitamin C protects immune system cells from oxidative damage and contributes to wound healing. Studies have shown that adequate vitamin C intake can shorten the duration of colds and relieve symptoms [5].
Vitamin C and skin health
Vitamin C is a crucial nutrient for the skin because it promotes collagen production. Collagen is the skin's main structural protein, supporting its firmness and elasticity. Through its antioxidant properties, vitamin C also protects the skin from damage caused by UV rays and environmental pollution. It is often used in skincare products to reduce the appearance of wrinkles and make the skin look more radiant [6].
Vitamin C and antioxidants
As a powerful antioxidant, vitamin C protects cells from the damaging effects of free radicals that cause oxidative stress. This oxidative stress can lead to cell damage and increase the risk of chronic diseases such as heart disease and cancer. Vitamin C helps neutralize these free radicals and reduce the risk of cell damage [7].
Vitamin C and iron absorption
Vitamin C improves the absorption of non-hemic iron found in plant foods. Non-hemic iron is less readily absorbed by the body than the hemic iron found in animal products. However, vitamin C can increase the bioavailability of plant-based iron by converting the iron into a more easily absorbed form. This is especially important for vegetarians and vegans who rely on plant-based iron sources [8].
Vitamin C and heart health
Vitamin C can help reduce the risk of cardiovascular disease by reducing inflammation in the body and lowering blood pressure. It also supports the flexibility of blood vessels, thus contributing to improved blood flow. Studies suggest that regular intake of vitamin C may reduce the risk of strokes and heart attacks [9].
Vitamin C and brain function
Vitamin C also plays a role in supporting cognitive function. It protects the brain from oxidative damage associated with aging and neurodegenerative diseases such as Alzheimer's disease. Studies show that people with higher vitamin C levels have better cognitive performance and a lower risk of age-related cognitive decline [10].
How does Vitamin C work in the body?
Vitamin C acts as a powerful antioxidant in the body, neutralizing free radicals and protecting cells from damage. It supports the production of collagen, which is crucial for skin, blood vessels, and connective tissue. It also plays a role in the regeneration of other antioxidants such as vitamin E and helps convert folic acid into its active form. Furthermore, vitamin C supports immune system function and improves iron absorption from plant foods [11].
Recommended dosage and use of Vitamin C
What is the recommended dosage?
The recommended daily intake (RDA) of vitamin C for adults is approximately 75 mg per day for women and 90 mg per day for men. Pregnant and breastfeeding women have slightly higher needs. An additional 35 mg per day is recommended for smokers, as smoking reduces vitamin C levels in the body. When taking supplements, a dosage of up to 1,000 mg per day may be considered to meet requirements or during periods of increased need, such as during a cold [12].
When should you take Vitamin C?
Vitamin C can be taken at any time of day, either with or without food. Because vitamin C is water-soluble, excess vitamin C is easily excreted in the urine. Supplements can be taken in the form of tablets, capsules, powder, or effervescent tablets. It is recommended to take vitamin C in smaller doses throughout the day to ensure consistent absorption [13].
Side effects and safety of Vitamin C
Is Vitamin C safe?
Vitamin C is considered very safe and well-tolerated, even in higher doses. Because it is water-soluble, excess vitamin C not needed by the body is excreted in the urine. However, extremely high doses (over 2,000 mg per day) can cause side effects such as stomach upset, diarrhea, and kidney stones. It is recommended to limit daily vitamin C intake to approximately 1,000 mg unless a doctor recommends a higher dose [14].
What are the side effects of Vitamin C?
Rare side effects of high vitamin C intake include stomach upset, bloating, and diarrhea. These side effects usually only occur at very high doses of more than 2,000 mg per day. People with kidney problems should be especially careful, as excessive vitamin C intake may increase the risk of kidney stones [15].
Vitamin C compared to other vitamins
Vitamin C vs. Vitamin E
Both vitamin C and vitamin E are powerful antioxidants that protect the body from oxidative stress. While vitamin C is water-soluble and acts in aqueous environments such as blood and cells, vitamin E is fat-soluble and protects cell membranes from damage. Both vitamins complement each other in their effects and often work together to support the body's antioxidant defenses [16].
Vitamin C vs. Zinc
Vitamin C and zinc are often combined in supplements to boost the immune system. While vitamin C promotes white blood cell production and acts as an antioxidant, zinc supports immune cell function and contributes to wound healing. Both nutrients are important for a strong immune system, and adequate intake can help prevent colds and infections [17].
Natural sources of Vitamin C
Vitamin C occurs naturally in many fruits and vegetables. The best sources include citrus fruits such as oranges, lemons, and grapefruit, as well as other fruits such as kiwis, strawberries, and papayas. Vegetables such as peppers, broccoli, Brussels sprouts, and spinach are also rich in vitamin C. A balanced diet including these foods can help meet your daily vitamin C needs [18].
Vitamin C in dietary supplements
Vitamin C is available in various supplement forms, including tablets, capsules, gummies, effervescent tablets, and powder. Many supplements combine vitamin C with other nutrients such as zinc or bioflavonoids to improve absorption and enhance antioxidant effects. Supplements may be a useful option when it is difficult to meet vitamin C needs through diet alone [19].
Final Thoughts on Vitamin C
Vitamin C, also known as ascorbic acid, is an essential vitamin that plays a central role in the immune system, skin health, and metabolism. It is a powerful antioxidant that protects cells from damage and supports wound healing. For people looking to boost their immune function, improve their skin health, or reduce oxidative stress, vitamin C is an important supplement that can be obtained either through food or supplements.