Vitamin C has been claimed to have a lot of functions, some of them have been proved by scientific studies, but some of them are still questionable. Here are some commonly claimed effects of vitamin c on human’s health.
The Common Cold
Although vitamin C has long been believed to cure the common cold, research shows that for most people, vitamin C supplements do not reduce the risk of getting the common cold or cure the cold after getting it. However, people who take vitamin C supplements regularly might have slightly shorter colds (about 1 day shorter in duration) or slightly milder symptoms. Using vitamin C supplements after cold symptoms start does not appear to be helpful.
Antioxidant
In the body, vitamin C acts as an antioxidant. It helps to protect cells from the damage caused by free radicals, which are formed when your body breaks down food for energy. People are also exposed to free radicals in the environment from cigarette / tobacco smoke, air pollution, ultraviolet light from the sun and radiation. The buildup of free radicals can cause aging and may possibly cause cancer and heart disease.
Cancer Prevention and Treatment
Many population based studies suggest that people with regularly high intakes of vitamin C-rich foods might have a lower risk of getting cancer, such as skin cancer, cervical dysplasia, lung cancer, colon cancer or breast cancer. On the other hand, the foods rich in vitamin C also contain many other beneficial nutrients, so it is difficult to determine the role of vitamin C in preventing cancer. Moreover, vitamin C supplements do not seem to have any effect on preventing cancer.
In addition, it is not clear that taking large doses of vitamin C will cure cancer or help cancer treatment. Also, some doctors are concerned that large doses of dietary vitamin C supplements may interfere with the chemotherapy medications and radiation therapy for cancer.
Cardiovascular Disease
People who eat lots of fruits and vegetables seem to have a lower risk of cardiovascular disease. However, it is still unknown that whether vitamin C is the one that helps prevent cardiovascular disease, such as heart attack or stroke. Vitamin C itself doesn’t lower cholesterol levels or reduce the overall risk of cardiovascular disease, but it may help protect arteries against oxidative damage. Some studies suggest that vitamin C may prevent the progression of hardening of the arteries and the build-up of plaque, which can cause heart attack. Even though the relationship between vitamin C and cardiovascular disease is not very clear, studies suggest that people with low levels of vitamin C may be more prone to have a heart attack, stroke or peripheral artery disease. Still, there is no evidence to prove that taking vitamin C supplements will help or cure these conditions.
Age-related Macular Degeneration (AMD) and Cataracts
AMD and cataracts are two of the leading causes of vision loss in older people. Some researchers do not believe that vitamin C affect the risk of getting AMD. However, research suggests that vitamin C combined with other nutrients might help keep early AMD from worsening into advanced AMD. Some other researchers believe that a combination of vitamin C, zinc, beta-carotene and vitamin E may benefit people who have advanced AMD.
Taking vitamin C higher than 300 mg/day for a number of years may have a protective effect on cataracts. However, a 7-year controlled intervention trial demonstrates that there is no relationship between vitamin C intake and cataracts prevention or progression. Like other claimed health benefits, more research is needed to clarify the relationship between vitamin C and AMD/cataracts.
Collagen Synthesis
Collagen is an important protein and structural component of blood vessels, tendons, ligaments, and bone. Our body requires vitamin C to make collagen. It is also needed to help wounds heal and sometimes used in anti-aging products.
Other Benefits
Vitamin C helps our bodies absorb iron from plant-based foods and helps the immune system work properly to protect the body from disease. Some studies also suggest that taking vitamin C along with vitamin E may help prevent pre-eclampsia (a common cause of premature births) in women who are at high risk. Vitamin C may also reduce effects of sun exposure, such as sunburn or redness.
References:
- http://ods.od.nih.gov/factsheets/VitaminC-QuickFacts/
- http://www.nlm.nih.gov/medlineplus/druginfo/natural/1001.html
- http://www.nlm.nih.gov/medlineplus/ency/article/002404.htm
- http://edis.ifas.ufl.edu/pdffiles/FY/FY21500.pdf
- http://www.aoa.org/x11814.xml
- http://ods.od.nih.gov/factsheets/vitaminc
- http://www.nlm.nih.gov/medlineplus/ency/article/002145.htm
- http://www.umm.edu/altmed/articles/vitamin-c-000339.htm
- http://lpi.oregonstate.edu/infocenter/vitamins/vitaminC/index.html
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