Vitamin C is a water-soluble vitamin that cannot be stored by the body, so it must be ingested each day. It plays a very important role in making collagen, an essential protein for building healthy bones and teeth, blood vessels, cartilage, tendons, and ligaments. It is also needed to form and repair the tissues in all parts of the body, including the skin. Vitamin C is an antioxidant and helps prevent damage to cells and DNA by neutralizing free radicals. It also aids in iron absorption from non-heme foods, making it an important nutrient for people with hemochromatosis, an inherited condition in which the body absorbs too much iron and stores it in tissue and organs.
Getting enough vitamin C from food is important, and many studies suggest that it can help reduce the risk for certain conditions, including the common cold, some cancers, heart disease, stroke, and atherosclerosis (the build up of plaque in blood vessels). Vitamin C is also known as an immune system booster. But is it possible to get too much of this nutrient? And does chugging the large doses of Vitamin C found in supplements really work to boost the immune system and fight off the common cold?
The evidence supporting the use of high-dose IV vitamin C in cancer patients is limited and inconsistent. In some animal studies, combining vitamin C with certain anticancer drugs has made them more effective, but the results from human clinical trials have been mixed. Some studies have shown that high-dose vitamin C improves quality of life in cancer patients, while others have reported no benefit.
Some laboratory and animal studies have shown that combining vitamin C with certain drugs can make them more toxic or less effective. However, these effects have not been seen in human clinical trials of IV high-dose ascorbic acid.
Other studies have shown that vitamin C may prevent the development of osteoarthritis (OA), which is when the cartilage between joints breaks down, putting pressure on bones and joints. Vitamin C is an antioxidant and works with enzymes to help keep cartilage intact. Some research also suggests that a diet high in vitamin C and other nutrients protects against OA.
A randomized controlled trial in more than 14,000 people found that one-year supplementation with vitamin C did not affect the risk of ischemic stroke or other types of stroke. However, other studies have found that taking vitamin C supplements can decrease your risk of stroke by lowering the level of oxidative stress in the blood.