Vitamin C is a water-soluble vitamin used to treat and prevent a wide variety of conditions. Often, people use it to prevent or treat the
common cold. However, there are other claimed uses of vitamin C as well, such as for reducing the risk of
heart disease. Some of these uses are more valid than others.
The vitamin has several different effects in the human body, such as:
- Antioxidant -- Many of the effects of vitamin C can be attributed to its antioxidant effects. As an antioxidant, it helps prevent the formation of free radicals, damaging molecules or atoms that can start a chain reaction of cellular damage. Free radicals play a role in various age-related conditions, such as cancer and heart disease.
- Immune function -- There are numerous different proposed mechanisms by which vitamin C may improve immune function. At this time, it is not entirely clear how the vitamin stimulates the immune system.
- Iron absorption -- Vitamin C aids in the absorption of iron from the digestive tract into the body.
- Various metabolic pathways and synthesis processes -- It is important for many different crucial processes in the body, including forming cartilage and proteins and building or breaking down numerous other compounds or tissues in the body.
Vitamin C may be effective for several different uses. However, there is much controversy about some uses, such as for the
common cold (see Does Vitamin C Work? for more information).
Dosing Information for Vitamin C
Both RDAs (recommended dietary allowances) and UL (tolerable upper limit) dosing recommendations are available for vitamin C. Some people (such as smokers) may need more than others.
Most people do not experience side effects with vitamin C (at normal doses). However, some people may experience side effects (especially with high doses), including, but not limit to:
(Click Vitamin C Side Effects to learn more, including potentially serious side effects that you should report immediately to your healthcare provider.)
Normal doses are probably safe for most people, but high doses can cause problems. Some people may be more likely to experience problems due to vitamin C. Therefore, you should talk with your healthcare provider prior to taking it if you have:
- Cancer (or a history of cancer)
- Diabetes
- Glucose 6-phosphate dehydrogenase deficiency
- Certain problems related to iron, including iron overload, hemochromatosis, thalassemia, or sideroblastic anemia
- Kidney stones
- Sickle cell disease
- Any allergies, including allergies to foods, dyes, or preservatives.
Also, let your healthcare provider know if you are:
Make sure to tell your healthcare provider about all other medicines you are taking, including prescription and non-prescription medicines, vitamins, and herbal supplements.
(Click Vitamin C Safety for more information, including any available warnings and precautions.)
What If I Take a Vitamin C Overdose?
An overdose is unlikely to cause serious problems, since it is a water-soluble vitamin (which means that any excess is usually excreted through the urine). However, high doses of vitamin C have been reported to cause problems in some people.
