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Vitamin C

Vitamin C (ascorbic acid) is an antioxidant and reducing agent found in certain foods. Humans cannot synthesize vitamin C, and it can be obtained only through selective dietary intake or with OTC supplements. This vitamin might help prevent some cancerscardiovascular disease, and even the common cold. Although a wide range of health benefits have been ascribed to vitamin C, these claims are supported by evidence that varies in its depth, character, and veracity.

Almost all fruits and vegetables contain some vitamin C. Citrus fruits are commonly known sources, but other foods with high vitamin C content include:

A link is well established between vitamin C levels and thyroid function, making hyperthyroidism and thyrotoxicosis significant risk factors.

People at risk for vitamin C deficiency include babies who are fed only cow's milk or plant-based beverages (almond milk) during the first year of life, and pregnant and lactating women. Individuals with disease of the small intestine such as Crohn's, Whipple, and celiac, as well as those who undergo gastric bypass surgery, also are at risk.

Other contributors to vitamin C deficiency include:

Vitamin C deficiency can have many implications, including:
  • Impaired immune function
    Vitamin C deficiency can make people more susceptible to infections.
  • Poor wound healing
    Vitamin C deficiency can delay wound healing and cause previously healed wounds to open.
  • Fragile skin and blood vessels
    Vitamin C deficiency can lead to fragile skin and blood vessels, which can cause gingival hemorrhages and petechiae.
  • Scurvy
    A major vitamin C deficiency can lead to scurvy, a disease that causes bone and blood vessel disease, bleeding in the hands and feet, anemia, bruising, and poor wound healing. Other symptoms of scurvy include swollen, bleeding gums that may become purple and spongy, loosened teeth, skin hemorrhages, a “scurvy rash” that shows up as red or blue spots on the skin, easily bruised skin, rough, scaly skin, swollen legs, and dry, brittle hair that coils like a corkscrew.
  • General unwellness
    People with low vitamin C may feel generally unwell with nausea and a poor appetite. Some people with vitamin C deficiency report flu-like symptoms.

According to NIH, the USRDAs for vitamin C are as follows:

People who smoke may need an additional 35 mg/day.

Although high vitamin C intake does not appear to cause excess iron absorption in healthy individuals, chronic consumption of high doses of vitamin C might result in tissue damage due to iron overload in those with hereditary hemochromatosis.

Although no acute toxic dose for vitamin C has been determined, the chronic toxic dose is more than 2 g/day.

Drug Interractions:

Vitamin C may decrease the efficacy or levels of omadacycline by inhibiting gastrointestinal absorption. This applies only to the oral form. Optimally, dosing of tetracyclines and vitamin C should be separated and closely monitored if they must be used together.

Other medications, including aluminum, chemotherapy drugs, estrogen, protease inhibitors, statins, niacin, and warfarin, may also interact with vitamin C.

Paddy Kalish OD, JD and B.Arch

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