Vitamin C is a water-soluble vitamin also known as ascorbic acid. In the 18th century the importance of fresh fruit and vegetables was acknowledged when it became apparent that many sailors were developing a condition called scurvy. During long voyages, all the fruit and vegetables were quickly eaten, leaving only preserved meat and cereals for a long part of the journey.
Studies done in 1747 by a British doctor named James Lind, found that if sailors ate citrus fruit they would recover from scurvy. Nearly two centuries later ‘vitamin C’ was isolated from citrus fruits and found to be the compound responsible for preventing scurvy.
Vitamin C is required for the formation of collagen, teeth, bones and capillaries, is an antioxidant and assists the absorption of iron.
Why you may need vitamin C
Enhances iron absorption – taking vitamin C with iron can increase the absorption of non-haeme iron. Iron is available in two forms – ‘haeme’ and ‘non-haeme’. Haeme iron is found in meat, fish and poultry while non-haeme is present in these foods plus vegetable, fruit, grains and legumes. Iron absorption is enhanced by vitamin C.
Common cold, immune support, recurrent infections – studies have found that vitamin C can decrease the duration and severity of symptoms of a cold or flu.
Lead toxicity – consuming dietary sources of vitamin C lowers lead levels in the blood.
Cataracts – lower levels of vitamin C in the lens have been found in patients with cataracts compared to patients with no cataracts. Plus vitamin C in the lens declines as cataracts develop. Supplementing with vitamin C for over 10 years may reduce the development of cataracts.
Periodontal disease – deficiency is related to increased gum bleeding or gingival inflammation without other symptoms of scurvy. Studies show bleeding was reduced with vitamin C supplementation.
Smoking – requirements are higher in smokers than non-smokers. Vitamin C might reduce oxidative stress caused by the large number of free radicals in cigarette smoke.
Wound healing – accelerated with vitamin C supplements.
Asthma – lower levels of vitamin C have been reported in people with asthma.
Osteoarthritis – studies have found that vitamin C can reduce the risk of cartilage loss and further deterioration in people with osteoarthritis.
How much do you need?
Recommended Daily Intake (RDI)
Adults (over 19 years): 45mg daily
Pregnancy: 60mg daily
Breastfeeding: 85mg daily
Children 9-18 years: 40mg daily
Symptoms of deficiency
Vitamin C deficiency may lead to scurvy which consists of the following symptoms – poor wound healing and ulceration, fatigue, shortness of breath, aching of the limbs, easy bruising, inflamed bleeding gums, anemia, and bones, teeth and blood vessels develop abnormally in children.
The best dietary sources include – guava, papaya, broccoli, strawberries, cauliflower, mango, parsley, asparagus, bok choy, tomato, rosehips, citrus fruits such as oranges and grapefruit.
Other reasons why you may need more
Vitamin C is very sensitive and great losses occur with storage and cooking. Boiling leaches vitamin C into the cooking water. You can use this water in soups, gravies etc.
If you find that your diet is limited to processed foods with little fresh fruit and vegetables, your need for vitamin C may be heightened. In addition stress, pollution, infection, surgery and allergies may increase your requirements.
- If you have a history of kidney stones or kidney / renal failure, consult your healthcare practitioner before supplementing with over one gram of vitamin C daily. Vitamin C may increase oxalate levels in the urine of some people. Use with caution in renal failure or oxalate kidney stones.
- Vitamin C can increase iron absorption, which could exacerbate these conditions: haemochromatosis, sickle cell anemia, sideroblastic anemia or thalassaemia.
- Diabetes mellitus – doses over one gram daily may interfere with diagnostic tests: blood glucose can cause an incorrect ‘negative’ result; urinary glucose can cause an incorrect ‘positive’ result.
- Some individuals may be sensitive to vitamin C and develop diarrhoea.