In the body, Vitamin C acts as an antioxidant, helping to protect cells from the damage caused by free radicals. Free radicals are compounds formed when our bodies convert the food we eat into energy. People are also exposed to free radicals in the environment from cigarette smoke, air pollution, and ultraviolet light from the sun.
The body also needs vitamin C to make collagen, a protein required to help wounds heal. In addition, vitamin C improves the absorption of iron from plant-based foods and helps the immune system work properly to protect the body from disease.
› Health benefits
Scientists are studying vitamin C to understand how it affects health. Here are several examples of what this research has shown.
The common cold
Although vitamin C has long been a popular remedy for the common cold, research shows that for most people, vitamin C supplements do not reduce the risk of getting the common cold. However, people who take vitamin C supplements regularly might have slightly shorter colds or somewhat milder symptoms when they do have a cold. It may also reduce the severity of an allergic reaction. Using vitamin C supplements after cold symptoms start does not appear to be helpful.
The adrenal glands are located in the kidneys and produce hormones, such as cortisol, that regulate your body. Research shows that the adrenals are among the organs with the highest concentration of vitamin C and require this vitamin to function properly.
Cancer prevention and treatment
People with high intakes of vitamin C from fruits and vegetables might have a lower risk of getting many types of cancer, such as lung, breast, and colon cancer. However, taking vitamin C supplements, with or without other antioxidants, doesn’t seem to protect people from getting cancer. People being treated for cancer should talk with their oncologist before taking vitamin C or other antioxidant supplements, especially in high doses.
Age-related macular degeneration (AMD) and cataracts
AMD and cataracts are two of the leading causes of vision loss in older people. Researchers do not believe that vitamin C and other antioxidants affect the risk of getting AMD. However, research suggests that vitamin C combined with other nutrients might help slow AMD progression.
People who eat lots of fruits and vegetables seem to have a lower risk of cardiovascular disease. Researchers believe that the antioxidant content of these foods might be partly responsible for this association because oxidative damage is a major cause of cardiovascular disease. However, scientists aren’t sure whether vitamin C itself, either from food or supplements, helps protect people from cardiovascular disease. It is also not clear whether vitamin C helps prevent cardiovascular disease from getting worse in people who already have it.
› How much do I need?
The recommended average daily intake of vitamin C depends on age and gender. For women, the recommended intake also increases during pregnancy and when lactating. Adults age 19+ years: 90 milligrams daily for men, 75 milligrams for women. Pregnant women age 19+ 85 milligrams daily; lactating women 120 milligrams daily. If you smoke, add 35 mg to the above values to calculate your total daily recommended amount.
Vitamin C has low toxicity and is not believed to cause serious adverse effects at high intakes. The most common complaints are diarrhea, nausea, abdominal cramps and other gastrointestinal disturbances due to the osmotic effect of unabsorbed vitamin C in the gastrointestinal tract.
› In foods
Fruits and vegetables are the best sources of vitamin C. You can get recommended amounts of vitamin C by eating a variety of foods including the following:
- Citrus fruits (such as oranges and grapefruit) and their juices, as well as red and green pepper and kiwifruit, which have a lot of vitamin C.
- Other fruits and vegetables—such as broccoli, strawberries, cantaloupe, baked potatoes, and tomatoes—which also have vitamin C. Some foods and beverages that are fortified with vitamin C. To find out if vitamin C has been added to a food product, check the product labels.
The vitamin C content of food may be reduced by prolonged storage and by cooking. Steaming or microwaving may lessen cooking losses. Fortunately, many of the best food sources of vitamin C, such as fruits and vegetables, are usually eaten raw.
› Dietary supplements
Most multivitamins have vitamin C. Vitamin C is also available alone as a dietary supplement or in combination with other nutrients. The vitamin C in dietary supplements is usually in the form of ascorbic acid, but some supplements have other forms, such as sodium ascorbate, calcium ascorbate, other mineral ascorbates, and ascorbic acid with bioflavonoids. Research has not shown that any form of vitamin C is better than the other forms.
Source: National Institutes of Health, Office of Dietary Supplements
Please consult your health care provider before making changes to your vitamin/supplement regimen.