Ascorbic acid (vitamin c)

  • Our verdict: 2 - with reservations, otherwise relatively ok
  • Latest update & fact check: 30.6.2024 - Rebecca Taylor, CNP
  • Origin: It is produced synthetically and does not come from natural sources.

Ascorbic acid, commonly known as Vitamin C, is a water‑soluble vitamin crucial for various bodily functions. It appears as a white to light yellow crystalline powder with a slightly acidic taste. As a potent antioxidant, ascorbic acid helps protect cells from damage caused by free radicals. It is also essential for the synthesis of collagen, which is vital for the maintenance of skin, blood vessels, bones, and cartilage.


Vitamin C can be found naturally in various fruits and vegetables, particularly citrus fruits, strawberries, kiwi, bell peppers, and leafy greens. Where ascorbic acid is synthesized artificially in laboratories. The commercial production of ascorbic acid generally involves the fermentation of glucose obtained from corn starch, followed by chemical synthesis processes to convert glucose into ascorbic acid.


  • Antioxidant properties: Neutralizes free radicals, preventing oxidative stress and damage to cells.
  • Collagen synthesis: Vital for the production of collagen, necessary for wound healing and maintaining the integrity of skin and connective tissues.
  • Immune support: Enhances the immune system by supporting various cellular functions.
  • Iron absorption: Increases the bioavailability of non‑heme iron from plant‑based foods.

How is it working in food?

  • Preservative: Prevents oxidation, extending shelf life.
  • Flavour enhancer: Maintains the natural flavour of foods.
  • Colour stabilizer: Preserves the natural color of fruits and vegetables.
  • Nutrient fortification: Adds nutritional value to food products.

Uses in Ultra‑Processed Foods

  • Antioxidant: Protects food from oxidative damage, which can lead to rancidity and loss of quality. Used in products like processed meats, oils, and snack foods to prevent spoilage and extend shelf life.
  • Preservative: Inhibits the growth of microorganisms that can cause foodborne illnesses. Commonly added to canned and packaged foods to maintain freshness and safety over extended periods.
  • Colour stabilizer: Maintains the natural appearance of foods by preventing discoloration due to oxidation. Used in fruit juices, cut fruits, and vegetables to keep them looking fresh and appealing.
  • Flavour enhancer: Preserves the natural taste of food products by protecting them from oxidative changes. Included in beverages, jams, and sauces to maintain their original flavor profiles.
  • Nutrient fortification: Enhances the nutritional value of foods, particularly those lacking in essential vitamins. Added to breakfast cereals, snack bars, and other fortified foods to boost their Vitamin C content.

Health Considerations

  • Recommended Intake: The Recommended Dietary Allowance (RDA) for adults is 90 mg/day for men and 75 mg/day for women. Higher doses may be required for smokers and pregnant or breastfeeding women.
  • Kidney stones: High doses of Vitamin C (more than 2,000 mg/day) can increase the risk of kidney stone formation in susceptible individuals.
  • Gastrointestinal issues: Excessive intake can cause diarrhea, nausea, and abdominal cramps.
  • GMO concerns: The majority of ascorbic acid is made using GMO corn. There are ongoing studies and debates on the safety of GMOs. 
  • Interactions: High doses may interfere with certain medical conditions and medications, such as anticoagulants and chemotherapy drugs.
  • Deficiency: Insufficient intake can lead to scurvy, characterized by fatigue, gum disease, and joint pain.


  1. Institute of Medicine. (2000). Dietary Reference Intakes for Vitamin C, Vitamin E, Selenium, and Carotenoids. National Academy Press.
  2. Carr, A.C., & Frei, B. (1999). Toward a new recommended dietary allowance for vitamin C based on antioxidant and health effects in humans. The American Journal of Clinical Nutrition, 69(6), 1086‑1107.
  3. Naidu, K.A. (2003). Vitamin C in human health and disease is still a mystery? An overview. Nutrition Journal, 2(1), 7.
  4. Padayatty, S.J., Katz, A., Wang, Y., Eck, P., Kwon, O., Lee, J.H., Chen, S., Corpe, C., Dutta, A., Dutta, S.K., & Levine, M. (2003). Vitamin C as an antioxidant: evaluation of its role in disease prevention. Journal of the American College of Nutrition, 22(1), 18‑35.