What Do We Know About Vitamin C?

What Do We Know About Vitamin C?

Vitamin C, also known as ascorbic acid, was recognized long before it was discovered and isolated through its effects in treating scurvy. Scurvy, a disease caused by severe vitamin C deficiency, led to symptoms such as bleeding gums, anemia, slow wound healing, and bruising. Among various attempted treatments, only citrus fruits (oranges and lemons) showed positive effects on the disease, saving many lives. Vitamin C was discovered in 1912 and isolated in 1928. It belongs to the group of water-soluble vitamins and serves as a primary antioxidant with many essential roles in the body:

• Strengthens cell walls and blood vessels
• Supports hemoglobin production in red blood cells
• Aids iron absorption from food, helping prevent anemia
• Essential for collagen formation
• Boosts the immune system
• Reduces the risk of chronic cardiovascular diseases
• Helps maintain good memory

How Does Vitamin C Perform its Antioxidant Role?

Ascorbic Acid ↔ Dehydroascorbic Acid
By releasing two protons and two electrons, ascorbic acid converts to dehydroascorbic acid. This redox system is responsible for the antioxidant effect of ascorbic acid. Under physiological conditions, vitamin C donates an electron to stabilize many free radicals. Ascorbate protects against LDL protein oxidation (low-density lipoproteins), assists in converting iron to ferritin, reduces free radicals like the hydroxyl radical, superoxide radical, hypochlorous acid, and regenerates the antioxidant potential of vitamin E by transferring an electron to the tocopherol radical.

Vitamin C Deficiency

Vitamin C deficiency is rare in developed countries, but it may occur due to:

• Diet low in vitamin C
• Smoking (both active and passive)
• Alcohol and drug abuse

If vitamin C deficiency is prolonged, symptoms may include:

• Scurvy (in severe deficiencies)
• Skin spots and blemishes (due to damaged blood vessels)
• Weak immunity
• Anemia
• Fatigue and weakness
• Swollen and bleeding gums
• Hair loss
• Delayed wound healing

Foods Rich in Vitamin C:

Optimal daily doses of vitamin C are 70–150 mg, with any excess excreted in the urine. High-dose supplementation (e.g., 2000–3000 mg/day) may lead to overdose, causing:

• Diarrhea and nausea
• Digestive issues
• Kidney stones
• Liver damage
• Increased excretion of oxalate (a vitamin C metabolite)

Stability of Vitamin C

Vitamin C becomes chemically unstable under certain conditions, decomposing at 190°C. Cooking reaches 100°C, which does not significantly degrade vitamin C, but frying at higher temperatures can, as does prolonged boiling, where ascorbate is exposed to 100°C for longer. The solubility of vitamin C also leads to its loss in cooking water. It’s proven that vitamin C from different foods does not dissolve at the same rate. Broccoli retains vitamin C the longest compared to other fruits and vegetables, and freshly picked foods stored in the refrigerator for a few days do not lose significant vitamin C amounts.

Natural vitamin C, besides ascorbic acid, includes various flavonoids, factor K, and rutin (a type of complex sugar). In contrast, synthetic vitamin C only provides pure ascorbic acid, produced artificially, which means natural vitamin C has a far more effective impact than synthetic ascorbic acid.