Getting enough vitamin C is important for your health. Discover why and how to boost your intake.

Vitamin C is an antioxidant and essential nutrient known for its ability to prevent scurvy and strengthen the immune system. It is also a powerful anti-inflammatory and may help reduce the risk of cancer.

Immune Boost

In the immune system, vitamin C enhances the function of white blood cells known as lymphocytes and phagocytes. It has been shown to protect these cells from self-inflicted oxidative damage, promotes the production of interferons, and stimulates the synthesis of other immune system proteins.

Large population studies have found that a high intake of fruits and vegetables containing vitamin C can reduce the risk of cardiovascular disease, especially when the diet includes fruits and vegetables rich in potassium. In addition, a number of observational and controlled trials have suggested that a high intake of supplemental vitamin C may prevent the common cold and shorten its duration.

Vitamin C is a water-soluble vitamin that most people can get from foods and supplements, except those with severe intestinal malabsorption or cachexia. It's also important to note that since vitamin C enhances non-heme iron absorption, high intakes can lead to excess iron accumulation if eaten in conjunction with certain conditions such as hereditary hemochromatosis. The recommended daily intake of vitamin C is 75 mg per day for women and 90 mg per day for men. It can be obtained from many food sources including citrus fruits, berries and some vegetables. In addition, a wide variety of supplements is available, including ascorbic acid and calcium ascorbate, ascorbate with bioflavonoids, and combination products such as Ester-C.

Antioxidant Power

A water-soluble vitamin with the chemical name L-ascorbic acid, vitamin C is essential to all mammals and other animals that can't synthesize it, as well as to plants. It is required for the synthesis of certain adrenaline hormones and collagen, the protein that makes up bones, teeth and cartilage. It also protects cells from oxidative damage and helps iron absorption in the gut. Vitamin C is commonly known for preventing and treating scurvy, a disease caused by vitamin C deficiency.

The body's natural levels of vitamin C are maintained at millimolecular concentrations in leukocytes and some tissues, and in extracellular fluids at micromolar concentrations. Because it enhances nonheme iron absorption, high intakes of vitamin C might lead to excessive ferritin levels in some individuals, particularly those with hereditary hemochromatosis.

Several studies have shown that vitamin C can reduce the risk of cardiovascular disease. However, clinical intervention trials have not consistently shown a beneficial effect of vitamin C supplementation on cardiovascular outcomes (32, 33). Vitamin C may help promote skin health by increasing the minimal erythemal dose (MED) for UV irradiation and by stimulating production of interferons in the skin. Vitamin C is also a potent antioxidant that can interact with vitamin E to boost the skin's protection against UV-induced oxidative damage and sunburn (34). (2)

Vital Health

Vitamin C's role as an antioxidant enables it to protect indispensable molecules in the body -- such as proteins, lipids (fats), carbohydrates and nucleic acids (DNA and RNA) -- from damage. It also plays an important role in redox (reduction-oxidation) recycling of other important antioxidants, such as Vitamin E.

Although Linus Pauling argued in his 1970 book that high-dose oral vitamin C could prevent or cure the common cold, the bulk of the evidence shows that high-dose vitamin C is not effective at preventing or shortening a cold. However, some research suggests that large doses of IV vitamin C can help reduce the length of a cold by about one day and may boost immune function.

Most epidemiologic studies have found that a diet rich in a variety of fruits and vegetables is associated with a lower risk for most cancers, perhaps because vitamin C is necessary to support the production of certain natural carcinogen-fighting agents (nitric oxide synthases) in the body. Moreover, vitamin C may limit the formation of certain chemical carcinogens in the body (nitrosamines), modulate immune response and attenuate oxidative stress that can lead to cell mutations.