WebMD Feature Archive
The benefits of vitamin C
What can vitamin C do for your health?
Vitamin C (ascorbic acid) is a water-soluble vitamin. We can’t store it in the body, which means we need it from our diet every day.
"Vitamin C helps protect cells and keep them healthy," says Marie Murphy, a nutrition scientist at the British Nutrition Foundation. "It is also involved in the production of collagen, which maintains healthy connective tissues, important for the support and structure of tissues and organs including the skin, bones and blood vessels."
Vitamin C helps with wound healing, and consuming vitamin C increases the amount of iron we can absorb from plant sources, such as kale, broccoli and sprouts.
Vitamin C is one of many antioxidants that may protect against damage caused by harmful molecules called free radicals, as well as toxic chemicals and pollutants like cigarette smoke. Research suggests that free radicals can build up and contribute to the development of health conditions such as cancer, heart disease and arthritis.
What if you don’t get enough vitamin C?
People who don’t get enough vitamin C in their diets are at risk of getting scurvy, although it is very rare to find cases of scurvy in the developed world.
Signs that you are not getting enough vitamin C include bleeding gums, feeling lethargic, bone pain, and joint pain, says Alana MacDonald, a registered dietician and spokesperson for the British Dietetic Association. You might also have a vitamin C deficiency if wounds don’t heal or they break open after they appear to have healed.
If you eat a balanced diet it is unlikely that you will have a vitamin C deficiency. Many food companies fortify their products, including bread, cereal and soya milk, with vitamins. "The only time we see vitamin C deficiency nowadays is in people with very, very poor diets," says Alana. "People who don’t eat any fruit or veg, just processed food, may have a vitamin C deficiency."
How much vitamin C is enough?
"The recommended nutrient intake for adults is 40 milligrams of vitamin C per day," says Marie. "On average, adults in the UK have about 80 milligrams of vitamin C per day."
People who smoke need more vitamin C than the average person because smoking depletes vitamin C in the body’s tissue and blood. People who have had surgery also benefit from additional vitamin C to help their wounds heal.
Is it possible to have too much vitamin C?
So how dangerous is it to take large doses of vitamin C? "If you took a high dose of vitamin C, your body would just excrete it in your urine," says Alana. "Your body is quite smart at deciding how much of something you need."
However, large doses of vitamin C can give you diarrhoea, stomach pain and flatulence. A recent study has also found a link between taking vitamin C supplements-which typically contain 1 gram of vitamin C-and kidney stones. The Swedish study found that men who take vitamin C supplements are twice as likely to develop kidney stones as men who don’t take any dietary supplements. Men who take multivitamins don’t appear to increase their risk of developing kidney stones, and nor do men who get their vitamin C dose from eating fruit and vegetables. It is not known if these results apply to women.