A water soluble vitamin, also referred to as ascorbic acid. It is often present in citrus fruits, strawberries, broccoli, peppers, and potatoes. It is easily destroyed in food by cooking, and storage and in the body by smoking. The Recommended Daily Amount in the UK for vitamin C is 90mg for males and 75mg for females.
Vitamin C is a powerful antioxidant essential for over 300 metabolic processes in the body including tissue growth and repair, adrenal gland function and healthy gums. Vitamin C is also necessary for collagen production, the main protein substance in the human body.
A deficiency of vitamin C is a common cause of scurvy; a disease characterized by bleeding gums, poor wound healing and extensive bruising. Increased susceptibility to infection, hysteria and depression are also classic symptoms.
Immunity-There is considerable evidence that Vitamin C plays a vital role in the mechanisms of the immune system (1). A group of scientists with the largest medical literature database ‘Cochrane Collaboration Reviews’ found that intakes of vitamin C greater than 200mg reduced the number of cold symptoms (2).
Wound Healing– The role of Vitamin C for wound healing has been shown to be extremely effective according to a 1970’S double blind study which evaluated the use of vitamin C for the treatment of pressure sores (3). Furthermore, analysis of vitamin C levels in 21 hip fracture patients showed a significantly lower incidence of the development of bed sores in those with higher vitamin C levels (4).
Asthma-Much research has been undertaken in relation to the role of vitamin C and asthma. Much of which suggests asthmatics have a higher requirement of vitamin C than the general population (1). A number of studies indicate that elevated dietary intake of vitamin C may be associated with a reduced risk of asthma (5), (6), (7). In cases of only mild asthma, vitamin C levels have been shown to be low (8). A study involving 7,505 youths in the National Health And Nutrition Examination Survey showed a stronger association between antioxidants and the prevalence of asthma in children exposed to cigarette smoke (9). A study of 4,300 healthy subjects in Norway reported that vitamin C intake reduced coughing and wheezing in smokers having high oxidant stress (10).
Cardiovascular Health-The role of vitamin C in relation to cardiovascular health has also been the subject of much research with studies revealing there is a link between Vitamin C and improved cardiovascular function (11). Analysis of data from 6,624 U.S. men and women enrolled in the Second National Health and Nutrition Examination Survey concluded increased ascorbic acid intake may decrease the risk of coronary heart disease and stroke (12).
Colds, flu and Infections– Vitamin C contributes to the normal function of the immune system. Several studies agree that taking vitamin C at the onset of a cold can lessen the symptoms and duration of the cold. Recommended 1000-2000mg daily at the first signs of a cold. It appears to work by elevating levels of interferon, while also raising the activity of key immune cells. Interferons are key proteins that respond to bacteria and viruses and trigger the immune response. One study on individuals engaged in heavy exercise showed a reduction in cold risk of around 50% when supplementing with around 1000mg of vitamin C daily.
Post-exercise soreness- Vitamin C contributes to the protection of cells from oxidative stress- an action that is commonly referred to as being an ‘Antioxidant’ – substances that help protect the body from the harmful effects of free radicals. It is thought to be the action of excess free radicals that is partly responsible for the muscle pain and soreness associated with intense exercise. One study showed a reduction in pain and soreness following exercise when supplementing with 400mg vitamin C daily, for at least a couple of days before and after the training.
Vitamin C is extremely safe, it has low toxicity and is not believed to cause serious adverse effects however in large doses it may cause gastrointestinal complaints such as diarrhoea, abdominal distension or gas. The Tolerable Upper Intake Levels for Vitamin C is 2,000mg for both males and females.